How smart is a smart grid?

A smart grid is a computerized management system designed to distribute the power available to the grid in an efficient manner relative to demand while maintaining grid stability. It does not generate any power except in so far as it saves some energy that would be wasted with a less efficient system. Because of limited storage capacity a smart grid is also capable of maximizing energy use over only short periods; it will not solve the intermittency problem over longer ones. Consequently there will be extended periods over which the smart grid will have little or no renewable energy to deliver. Installation is also likely to be costly, and there are questions as to whether current designs based on computer simulations will work in practice.

As a geologist/geophysicist with no background in electrical engineering I had to think twice about writing this post, but smart grids are widely viewed as being an integral part of a green energy future and Energy Matters has never put up a post on them before. I don’t think I’ve made any gross errors in this one but I’m sure someone will let me know if I have.

Characteristics of a smart grid:

According to Wikipedia :

A smart grid is an electrical grid which includes a variety of operational and energy measures including smart meters, smart appliances, renewable energy resources, and energy efficiency resources. Electronic power conditioning and control of the production and distribution of electricity are important aspects of the smart grid.

And:

The improved flexibility of the smart grid permits greater penetration of highly variable renewable energy sources such as solar power and wind power, even without the addition of energy storage. Current network infrastructure is not built to allow for many distributed feed-in points, and typically even if some feed-in is allowed at the local (distribution) level, the transmission-level infrastructure cannot accommodate it. Rapid fluctuations in distributed generation, such as due to cloudy or gusty weather, present significant challenges to power engineers who need to ensure stable power levels through varying the output of the more controllable generators such as gas turbines and hydroelectric generators. Smart grid technology is a necessary condition for very large amounts of renewable electricity on the grid for this reason.

Figure 1 shows a layman’s layout of a smart grid:

Figure 1: A model set up of a smart grid network (data Vijayapriya & Kothari, 2011)

And figure 2 shows a layout of a small community smart (micro)grid for the more technically-minded:

Figure 2: Layout of a small community smart grid (data Guo et al 2012)

Smart grids regulate both electricity supply and demand in order to offset the impacts of spikes or other excursions in either, and in particular to achieve “peak load shaving”. There is, however, a difference in approach between the way they treat supply and demand. The supply side of the smart grid is reactive. It takes the input power and redistributes it to where it’s needed while maintaining frequency control and grid stability via sensors, high speed switches and other such electronic devices. The demand side is proactive. It interfaces supply with smart meters and smart devices in households, businesses etc. that the smart grid can turn on or off in order to match supply as closely as possible to the load curve – apparently with or without the consent of the home or business owner. As DOE puts it :

Demand response provides an opportunity for consumers to play a significant role in the operation of the electric grid by reducing or shifting their electricity usage during peak periods in response to time-based rates or other forms of financial incentives …. Methods of engaging customers in demand response efforts include offering time-based rates such as time-of-use pricing, critical peak pricing, variable peak pricing, real time pricing, and critical peak rebates. It also includes direct load control programs which provide the ability for power companies to cycle air conditioners and water heaters on and off during periods of peak demand in exchange for a financial incentive and lower electric bills.

I’ll simply observe here that time-of-use pricing has been around for years (the three major California utilities at my last count had no fewer than 46 different rates) and so far has had done little to shave peak load in the places where it has been applied. Direct load control may therefore be the only option, but whether the public would stand for it is another question.

Analysis of smart grid performance:

Smart grid performance is presently analyzed through computer simulations that concentrate on managing the impacts on grid stability of short-term fluctuations caused by intermittent wind and/or solar input and/or rapid changes in demand. The results of the Guo simulations from which Figure 2 comes are fairly typical and are summarized in the graphs reproduced below in Figure 3. I’m not suggesting that anyone tries to interpret what they mean, it’s just that results of this type tell us nothing about how the smart grid is likely to perform under real-life operating conditions – in particular whether it will be capable of filling demand using  intermittent generation. I’ve not been able to find any smart grid simulations that take actual generation data and plug them in to see what happens, although someone else may know of some:

Figure 3: Summary of results of Guo et al simulations.

Analyses like these in fact totally ignore the longer-term impacts of intermittency, such as protracted wind lulls and seasonal solar variations. The assumption seems to be that an adequate supply of renewable energy will always be available from somewhere and that the problem is simply one of distributing it efficiently without crashing the grid. And where is this adequate supply to come from? Well, when the wind and the sun fail it’s further assumed that storage capacity will be adequate to take up the slack. Which brings us to

Energy storage:

Smart grids are designed to handle only short-term supply and demand variations, with the assumption apparently being that the storage facilities shown in Figures 1 and 2 will be large enough to store energy generated during off-peak periods for re-use, as Figure 1 puts it. The clear implication here is that the storage systems need only be large enough to handle daily load changes.

And indeed energy storage large enough to handle daily load changes may be achievable – although costly – using current battery technology. But as discussed in numerous previous posts there is no way storage could be made anywhere near large enough to handle extended wind lulls or seasonal variations in solar output*. Consequently it must be expected that any smart grid, or even a number of interlinked smart grids, will often not have enough renewable energy to fill demand, whereupon fossil fuel generation will have to cover the deficit.

*This of course does not apply in countries like Norway, where existing hydro resources would be sufficient to store large amounts of surplus wind or solar power. But in such countries there would be little point in achieving high levels of wind and solar penetration when all of the generation already comes from hydro.

The final question is:

How reliable are smart grid simulations?

With the exception of the limited real-life examples discussed below all of the presently available data on smart grid performance are derived from computer simulations, which prompts the question posed above. And the answer is, probably not very reliable at all.

Merino et al 2012 provides an example from the Gorona del Viento project in the Canary Islands of simulations that developed a theoretical solution to the grid stability problem at high levels of wind penetration but which has obviously not worked in practice. (In theory grid stability can be maintained by keeping three hydro turbines as a spinning reserve. In practice the entire hydro pumping system has had to be used as a dynamic resistor to waste surplus wind power, stabilize the grid and match supply to demand rather than to store surplus wind energy.)

There are also some excellent articles from “Planning Engineer” at Judith Curry’s Climate etc. blog which go into the difficulties of predicting how a simulated high-renewables-penetration grid will work in practice. Here’s a quote from one of them:

Policies to increase wind and solar may lead to unprecedented changes for the bulk power system. No one can say with any certainty that our existing models and study approaches are sufficient to guarantee that new problems associated with new technology (and the interaction of such technology with conventional technology) will not emerge. For example, series compensators were put into long transmission lines to enable long distance transfers of power without having excessive voltage drops. As modelled they worked well and no problems were anticipated. In practice it was discovered that they could produce catastrophic results ….

And why use simulations anyway? Because anything else is too expensive. As Guo et al put it:

Experimental studies of large-scale smart grids are usually not economically feasible. As an evidence, even for a microgrid, where the number of distributed energy sources and intelligent loads is quite limited, there are only a handful of test platforms around the world.

In short, there are no guarantees that any smart grid will work as planned.

Existing smart grids

The closest I can come to an operating smart grid system where any data are available is King Island, Tasmania (population 1,600, peak load 2.5MW, annual electricity consumption ~10GWh). Details of the system are:

Installed capacity:

  • Diesel: 6.00MW
  • Wind: 2.45MW
  • Solar pv: 0.39MW
  • Total: 8.84MW

Frequency & grid stability control:

  • Dynamic resistor for load-shedding
  • 2 MVA flywheel-based uninterruptible diesel power supply
  • 3 MW/1.6 MWh “advanced” lead acid battery storage

Demand side response:

  • Power to electric water heaters can be interrupted.

Further details on the operating system, including some interesting graphs, can be found here, here, here and here.

Clicking on the “King Island Tasmania Live Grid” sidebar brings up (after a delay) a real-time flow diagram showing how generation is switched between the different control units to match demand while keeping frequency within a few percentage points of 50 hertz. There seems to be no doubt that the system works at least in so far as grid stability is concerned. But it took King Island several years to get to this point, and there are the following offsetting factors.

1.  The system is expected to supply only up to 65% of King Island’s demand with renewable energy, partly because of wind curtailment, partly because of lack of storage and partly because the wind farm is not large enough to generate enough power to fill annual demand anyway. The screenshot below, which I took at random a few days ago, shows 37% of the wind generation being curtailed by the dynamic resistor during a period of high-wind conditions when supply exceeded demand:

Figure 4: Screenshot of King Island grid flows during a period when wind generation exceeds demand

2.  With a 100% efficient system this curtailed power would be sent to storage – either to the batteries or the flywheel. But neither have anything like the storage capacity necessary to do this (the batteries can in fact store only enough power to supply island demand for about 16 hours). Consequently there are periods when the smart grid has no renewable energy to deliver, one of which is shown by the default values that appear before the real-time diagram activates. It’s not known whether King Island has yet met its 65% renewables goal, but the absence of press releases in the last couple of years suggests that it hasn’t.

3.  High costs. The project budget was initially estimated at $46 million but “was expected to come in well below this” (whether it did is not known, but even at $30 million the cost still comes out at about $10,000 per installed kilowatt). Needless to say the King Island project would not have gone ahead without subsidies, with the Commonwealth Government contributing up to a third of the total cost under its Renewable Energy Demonstration Program and Hydro Tasmania and CBD energy covering the rest “with support from the State Government”.

A final question is what the 21kW of “demand response” shown on the screenshot means. If it’s a measure of the savings generated by turning water heaters on and off then it’s hardly worth the effort.

The one remaining example I can find is the Pacific Northwest Smart Grid Demonstration Project, a much larger-scale effort which the U.S. Department of Energy described thus:

The Pacific Northwest Smart Grid Demonstration (PNWSGD), a $179 million project that was co-funded by the U.S. Department of Energy (DOE) in late 2009, was one of the largest and most comprehensive demonstrations of electricity grid modernization ever completed. The project was one of 16 regional smart grid demonstrations funded by the American Recovery and Reinvestment Act. It was the only demonstration that included multiple states and cooperation from multiple electric utilities, including rural electric co-ops, investor-owned, municipal, and other public utilities. No fewer than 55 unique instantiations of distinct smart grid systems were demonstrated at the projects’ sites. The local objectives for these systems included improved reliability, energy conservation, improved efficiency, and demand responsiveness.

And the results of the 16 smart grid tests? (No, I have no idea what an “instantiation” is either.) They are buried in 16 large pdf files accessible through the link shown above that I haven’t had the time or inclination to go through, but the only quantitative conclusion I could find (in Front Matter.pdf) was this:

This simulation showed that the region’s peak load might be reduced by about 8% if 30% of the region’s loads were responding to the transactive system.

While some of the $179 million spent on the program went towards installing equipment this single conclusion still sounds like a poor return on the amount of money invested.

Wrapping things up:

This brief and incomplete layman’s review of smart grids prompts the following conclusions:

  1. Grids must contain complex frequency and stability control mechanisms if they are to handle high levels of renewables penetration. Hence some kind of “smart grid” will be needed.
  2. Adding these mechanisms, however, is likely to be costly and there is no guarantee that they will work as planned.
  3. Even if they do work as planned inadequate storage capacity and intermittency will limit renewables penetration. Regardless of how well the smart grid performs technically there will be extended periods when renewable energy generation plus energy in storage are inadequate to fill demand.
  4. Backup fossil fuel generation will therefore always be required, although present-day smart grid designs implicitly take this requirement into account. It is in fact difficult to find a smart grid conceptual diagram which does not show a fossil fuel plant as part of the generation mix.

Endnote:  In an email he sent me after reviewing the draft post Euan Mearns posed the following questions:

Do Smart Grids offer real opportunity to integrate large amounts of variable renewable energy? Or are they simply another Green Dream born more out of hope than engineering?

I have to opt for the second conclusion. If the goal of a smart grid is ultimately to integrate large amounts of renewable energy with the grid then it won’t succeed. No smart grid is smart enough to generate electricity when the wind doesn’t blow and the sun doesn’t shine.

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139 Responses to How smart is a smart grid?

  1. singletonengineer says:

    Are supporters of smart grids generally also supporters of micro-grids (not connected to the main power grid) and the global grid, which promises to connect so many unreliable generators around the world and to rely on the hope that the wind is always blowing or the sun shining somewhere?

    All three offer limited opportunities which come at a cost in terms of both money and availability, yet suffer from lack of practical ability to meet their enthusiasts’ promises for universal application.

    They are examples of magical thinking in order to avoid the complexity and downsides that are necessary features of real-world solutions to real-world problems.

  2. Dave Rutledge says:

    Ii Roger,

    Good job.

    Interesting that the battery storage gives only 32 minutes of operation at full power. The dynamic resistors sound similar to those used for braking locomotives. Good cheap technology.

    I personally have viewed the current smart grid discussion as 90% marketing talk intended primarily for regulators, financial analysts, and funding agencies.

    Dave

    • Hugh Sharman says:

      I agree Dave! Politicians also swoon at the very word “smart”, a phenomenon I have been viewing here in Denmark for much of the past 20 years. It works too! “Smart grid research” gets open ended funding from any manner of Governmental, inter-governmental and quasi-Governmental (ie EU, OFGEM, DOE and the numerous governmentally funded rearch labs in the USA, etc) sources.

      Consumers everywhere seem especially resistant to “demand management blandishments. Here in Denmark (heading towards 50% wind penetration by power generation next year), daily demand patterns have hardly shifted in that time. Its “feasibility” would have been absolutely impossible without the giant battery (Norway/Sweden) next door.

      • Willem Post says:

        Hugh,

        With big enough wings (subsidies, energy storage) even pigs can be made to fly.

        Look at this folly in New England.

        The Block Island Wind Farm, after many years of dithering, likely will be operational in late 2016. It is located 3.8 miles east of Block Island, Rhode Island. It has five wind turbines, each with a capacity of 6 megawatt.

        Each turbine is about 589 feet tall. Total project cost is about $290 million. The service life is about 25 years. The annual wind energy production would be about 105,000 megawatt hour.

        If the major costs of 1) 25-year financing, 2) turn on investment, and 3) operation and maintenance are ignored, then the cost of energy production would be about 11.4 cent per kilowatt hour.

        If these costs were not ignored, the energy cost would be at least 20 cent. That would be about the price charged to utilities under a long-term power purchase agreement. This energy would be variable and intermittent, i.e., no wind, no energy. Other generators, likely gas-fired, would be required to serve electricity demand on a year-round basis.

        There is a much better and less costly alternative. A much larger quantity of energy could be bought from Hydro-Quebec at a cost to utilities of about 7 cent. That energy would have much less CO2 emissions per kilowatt hour than wind energy, and would be a steady, year-round supply, wind or no wind.

        A 1,000-megawatt transmission line, costing about $2.0 billion, could supply to Massachusetts and Rhode Island about 6,500,000 megawatt hour, at least 60 times at much as the above wind turbine system.

  3. Joe Public says:

    Thanks Roger, for your interesting explanations.

    1. By coincidence, Paul Homewood yesterday had a short posting on the opposite side of the coin.

    The EU’s proposal that countries have non-binding targets for interconnector capacity. For GB this to be 10% of ‘installed capacity’ by 2020, rising to 15% by 2030.

    Countries having a large amount of low load factor intermittents would have a proportionally higher obligation.

    https://notalotofpeopleknowthat.wordpress.com/2016/08/14/eu-targets-for-interconnector-capacity/

    2. Gotta love the reality skirted around within the explanation about ‘Methods of engaging customers in demand response efforts’

    Smart meters provide the facility to impose Maximum Demand Charges on domestic customers. Larger UK industrial & commercial users (generally >100kW) already have ½-hour metering. Their monthly unit cost is proportional to their peak ½-hour demand. If for example they run a 1kW electric fire during that peak period, their costs for running everything else – process, lighting, catering, DHW etc, is massively increased for the entire month.

  4. gweberbv says:

    “If the goal of a smart grid is ultimately to integrate large amounts of renewable energy with the grid then it won’t succeed. No smart grid is smart enough to generate electricity when the wind doesn’t blow and the sun doesn’t shine.”

    Integrating renewable production is not the same as bridging gaps between spikes of renewable production. Think about the German wind fleet in the year 2025: >60 GW onshore, >10 GW offshore.
    During a winter storm, one can easily expect to have 65 GW of wind production. Adding the must run capacities and inflexible producers in the power plant fleet, we might end up with a total production of 80 to 90 GW. What to do with this power? With the increased interconnector capacities of the year 2025 it will be probably possible to sell it to the neighbours (and the neighbours of the neighbours and so on) for maybe 10 Euros/MWh. But at the same time Germany is burning huge amounts of gas for space heating and water heating. Gas that costs 40 to 80 Euros/MWh (retail level). Connecting the electricity and the heating sector via intelligent devices that ‘know’ when excess electricity production drives prices below the level of natural gas will enable the integration of large amounts of renewable production (by converting them to heat).

    • Think about the German wind fleet in the year 2025: >60 GW onshore, >10 GW offshore. During a winter storm, one can easily expect to have 65 GW of wind production. Adding the must run capacities and inflexible producers in the power plant fleet, we might end up with a total production of 80 to 90 GW. What to do with this power? With the increased interconnector capacities of the year 2025 it will be probably possible to sell it to the neighbours (and the neighbours of the neighbours and so on) for maybe 10 Euros/MWh.

      No chance. France, Belgium, the Netherlands, the Czech Republic and Poland have already installed phase shifters to protect their grids from unwanted surges of German renewable energy, and it’s only 2016.

      http://www.politico.eu/article/strong-winds-in-germany-a-problem-in-central-europe/

      • depriv says:

        Selling is fine, in theory. Polluting of neighbouring grids is, what those PSTs are against. The loop currents through Middle-Europe are the results of inadequate nort-south capacity within Germany: and the surges are the results of the policy forced onto the network operators in Germany regarding wind power feed-in.

        With getting rid of this kind of ‘pollution’ of cross-border capacity the PSTs will actually allow the contolled trading.

        However, in practice: since all the mentioned countries are installing wind capacity like crazy, and since almost all of them will be quite in sync with the wind capacity in Germany, it’ll be a bit hard to sell anything.

      • Willem Post says:

        Roger,

        The likely wholesale price of German export energy would be MINUS $10 to $20/MWh during such overproduction events.

        Ii is likely there will be significant curtailment of wind and solar energy, because Germany will not be able to get rid of it.

        It is embarrassing, Germany has used its wealth to engage in a gigantic folly. It is unlikely others will follow its path.

        Nuclear is looking better and better.

        Invite the Chinese and Russians to build about (50) 1000 – 1200 MW reactors, at a total cost of $275 – $300 billion.

        Production would be 55000 MW x 8760 x 0.90 = 433,620,000 MWh/y, about 75% of what Germany generated in 2015.

        • Willem Post says:

          Addition to above comment:

          – Germany would have the same nuclear percent as France.
          – Germany, instead of the highest electric rates in Europe, would have one of the lowest.

      • Hugh Sharman says:

        Roger,

        Thanks for the politico link! I notice the story was dated March 2015. We are now in the third quarter of 2016, heading into 2017.

        I keep looking for an update on this story, so far without success!

        Germany is certainly back-pedalling on new wind and PV. A possible indicator of what is really happening is the blockage of Nordic (read Danish) wind exports into the EU by Germany because of congestion on the Nordic export inter-connectors.

        Maybe we must wait for the commissioning of the Czech and Polish phase-change transformers in 2017 to get the real story?

        What about other readers?

    • robertok06 says:

      @gweberbv

      “With the increased interconnector capacities of the year 2025 it will be probably possible to sell it to the neighbours (and the neighbours of the neighbours and so on) for maybe 10 Euros/MWh. ”

      How about NEGATIVE prices in the 100s Euros/MWh, like it happened already on May 8 of this year?

      “Based on EPEX SPOT data, the lowest price between 12:30 and 12:45 was EUR -178.01 EUR/MWh, with a weighted average of -144.78 EUR/MWh. Later in the day, prices went down even further to -374.00 EUR/MWh between 14:30 and 14:45.”

      • Willem Post says:

        roberto,

        That means Germany was PAYING big bucks to have others take its excess energy. Will this happen more and more?

        Remember, the legacy cost of the subsidized ENERGIEWENDE energy is about 18 – 20 eurocent/kWh.

        The legacy cost of Germany’s traditional energy is about 5 c/kWh.

        With 75% RE on the grid, the export COST/kWh would be 5 x 0.25 + 19 x 0.75 = 15.5 eurocent/kWh

        • Willem Post says:

          Addition to above comment:

          Here are some paragraphs from an article:

          On May 8, 2016, based on EPEX spot data,

          – The lowest export price was -178.01 euro/MWh, with a weighted average of -144.78 eur/MWh, between 12:30 and 12:45
          – Later in the day, prices went down even further to -374.00 eur/MWh, between 14:30 and 14:45

          On May 15, 2016, Germany met all but 300 MW of its energy demand with renewable energy (mostly wind and solar) for a few hours. At that time, Germany’s fossil fuel plants were also producing about 7700 MW. The excess energy was sold at negative prices, per EPEX spot data.
          http://www.bloomberg.com/news/articles/2016-05-16/germany-just-got-almost-all-of-its-power-from-renewable-energy#media-3

          Remember, the legacy cost of the ENERGIEWENDE energy is about 19 eurocent/kWh. The legacy cost of Germany’s traditional energy is about 5 eurocent/kWh. With, say 95% renewable energy on the grid, and energy generation at about 105% of demand, the COST of that energy mix would be (5c x 10%; traditional + 19c x 95%; renewable)/1.05 = 17.67 eurocent/kWh, of which about 5% is exported at significantly negative prices.

          No wonder Germany has been reducing its wind and solar build-outs, due to complaints and blockages from nearby countries and losing money on energy exports. With energy exports partially blocked by the PSTs, Germany could respond by:

          – Curtailing wind and solar energy production during windy and sunny periods, but that would attract adverse media attention.
          – Adding quick-starting, flexible, gas-fired, plant capacity, MW, but that would “lock-in” CO2 emitting fossil fuels and gas imports.
          – Building more north-south HVDC transmission grid, but that has been constrained due to NIMBY for more than 15 years.
          – Adding battery-based energy storage, but that would be expensive and take many years, because economically viable, utility-scale storage, suitable for seasonal variations, has not yet been invented.

          Germany is very rich in money and technology, unlike many other countries, and likely will find a way to make it work. It will be interesting to see how it all will turn out.

          • Depriv says:

            “With energy exports partially blocked by the PSTs…”

            That’s really a misundertanding. The cross-border capacity (to Czech and Poland) is blocked by unplanned (loop) flos and surges: both are handled with keeping significant part of the available capacity as reserve by the owner of the lines.

            The PSTs will/do block loop flows and surges, so the reserved capacity will/is free for auctions. So actually those PSTs are making extended trading possible.

            The problem is, that the grid (operators) in Germany were forced to use the mid-european grid as a kind of ballast to keep their stuff straight. The loop flows are the result of their inadequate north-south transfer capacity, the surges are the result of their slow and slowing PP building.

            With that ‘ballast’ removed nobody actually knows what will happen. The problems there are running far deeper than most would think.

          • Hugh Sharman says:

            @Depriv, I agree! It is a ticking time bomb!

            The lack of transfer capacity from the Nordic region to mainland Europe is driving down wholesale prices here with the highly knowable short-term consequences of the inevitable closure of dispatchable fossil and nuclear reserves while nothing to replace these can be remotely financeable.

            Dispatchable capacity is needed! Lemmings come to mind….

          • gweberbv says:

            Depriv,

            to me it seems quite obvious, what will happen when ‘loop flows’ are stopped and not fully replaced by controlled exports: i) Wind power in the northern part of Germany will be more curtailed as there is no other way to get rid of it. ii) Less conventional capacity in the southern part of Germany and Austria can be ramped down, as these are the regions where the loop flows usually end up.
            This implies that the common bidding zone that is Germany and Austria has to be split up in order to match north-south electricity trade with the physical limitations of the available interconnectors (while not using the grids of the neighbours as unwitting additional interconnector capacity).

  5. Rive says:

    “The assumption seems to be that an adequate supply of renewable energy will always be available…”

    Also an assumption (rarely mentioned) that there will be always adequate transfer capacity available at any given time, for free.

    Not seems very likely to happen.

    As I see, smart grids might be useful in four main areas.
    – with short term load reschedule it might set higher the daily minimal consumption, so it can give more room for the baseload PPs. This can make generation cheaper, and with NPPs, it can mean less carbon output.
    – with short term load reschedule it might lower the daily maximal consumption peaks, so the grid might be less demanding for load following PPs.
    – with short term load reschedule it might smooth out sudden load changes, so fast balancing plants would be less needed.
    – they can switch off distributed production fast on basis of load following. Yep, I’m talking about ‘plants’ like home solar or wind farms, which were prioritized so far, without much (logical) reason.

    But that’s almost all. The amount of freely switchable load is limited, so the impact of the whole ‘smart’ buzz is limited as well. It’s definitely not the Holy Grail, it never was and never will be.

    As it was already mentioned, the very basics of ‘smart grid’ is already around. Since limited usage would mean considerable savings for small costs, any (sane) provider would move in that direction anyway. To push it is just insane, it’ll just eat up all the savings it might mean.

    • Beamspot says:

      Just as a side note, the long distance power transfer is anything but easy. Integrating power from far away will be really challenging and only doable if local (<600Km) dispatchable power is available.

      Power grid is in fact a distributed parameter grid. Lightspeed is relevant, not mere SF, and almost everybody overlooks this point. Power reflections and stationary waves are important there, not only frequency stability/syncrhonization.

      • OpenSourceElectricity says:

        In China a power line with a length of 3284 km and a capacity of 12 GW on one system is under construction. The length is long enough to connect ireland with canada, to give a imagination. ABB and Siemens deliver equipment for this power line. Power transmission is a area of rapid development at the moment, after “sleeping” for 60 year.

        • Euan Mearns says:

          Links and verification please.

        • Beamspot says:

          Be warned that stability in those lines dpends on certain factors.

          Usually, interconnectors send part of the demanded power from one point to another point, not to a wide area, and only part of the power. The local satability has to be accomplished by local production that keeps the local re-distribution stable by adding the required power.

          Two hints:
          https://en.wikipedia.org/wiki/Electric_power_transmission
          https://en.wikipedia.org/wiki/Transmission_line

          That means that remote control of stability is phisically not doable. While the bulk of power can be send long distances, the short term control, reaction, stability control has to add the remaining part accordingly to the demand, and in real time, few milliseconds, not minutes.

          The bigger (relative) amount of power caming from far away, the higher the modulation ability of the local stability controllers, that have to be dispatchable by definition.

          This is overlooked totally by many people, and only those that had worked (or are working) with power grid distribution (and also RF, or even, as is my case, PCB level power distribution) know for sure. It is anything but simple, and have lots of implications, specially if electronic synchronization is used (as happens with PV inverters and last generations of wind turbined).

          They can lead to standing waves: https://en.wikipedia.org/wiki/Standing_wave

          Of course, all of this is doable, but this is another hidden high cost, not to talk about politics, conuntries, borders, import/exports, geostrategy.

          Continental scale grid is anything but simple, and the solution may be much more complex and expensive than many of those academic writers think (in fact, as they know, because this is an issue of – lack of – knowledge).

          And I would like to see how this integrates in a nort-south continent like America, that has a big part of its land within few hous (night or day in all the continent at once), not like Asia.

          Woud there be a huge interconnector between Alaska and Russia, that will bring power from Australia to USA, that is where the sun shined (Australia) at the peak consumption time in Christmas (in USA)?

          Will a party in Paris at middnight use electricity generated by PV in Kourou?

          And, any information about Loses (REE reports about 9% mean of lossed over the year in Spanish distribution grid) of the overall system? How big the impact of the increased power generation required wil be?

        • depriv says:

          He did not say that it’s impossible. He said only that it’s difficult and availabity of local source is a requirement.

          And that’s absolutely true. The loop delay for such a closed loop control is quite big, to guarantee that the system can be operated in stable manner (to guarantee that it’ll never go oscillating or such) is a nightmare, especially regarding the amount of power controlled.

          But that’s just half of the problem. The financial part of the thing is far worse than for an NPP.

  6. depriv says:

    “The assumption seems to be that an adequate supply of renewable energy will always be available…”

    Also an assumption (rarely mentioned) that there will be always adequate transfer capacity available at any given time, for free.

    Not seems very likely to happen.

    As I see, smart grids might be useful in four main areas.
    – with short term load reschedule it might set higher the daily minimal consumption, so it can give more room for the baseload PPs. This can make generation cheaper, and with NPPs, it can mean less carbon output.
    – with short term load reschedule it might lower the daily maximal consumption peaks, so the grid might be less demanding for load following PPs.
    – with short term load reschedule it might smooth out sudden load changes, so fast balancing plants would be less needed.
    – they can switch off distributed production fast on basis of load following. Yep, I’m talking about ‘plants’ like home solar or wind farms, which were prioritized so far, without much (logical) reason.

    But that’s almost all. The amount of freely switchable load is limited, so the impact of the whole ‘smart’ buzz is limited as well. It’s definitely not the Holy Grail, it never was and never will be.

    As it was already mentioned, the very basics of ‘smart grid’ is already around. Since limited usage would mean considerable savings for small costs, any (sane) provider would move in that direction anyway. To push it is just insane, it’ll just eat up all the savings it might mean.

  7. renewstudent says:

    The review is helpful, but its concept of smart grids is rather limited.
    It is true that demand management can only shift demand peaks by a few hours or in the extreme (with interuptable contracts) a day or so, similarly storage system like batteries can only meet lulls for a few hours or at best a day or so, whereas there can be long lulls in wind and solar inputs, for several days or even a week, sometimes across wide areas. However, studies have suggested that it will be rare for whole continents to be entirely becalmed and cloudy for long periods, so if they are spread widely enough, supergrid interconnectors can often deal with lulls in some parts by trading power from where there is surplus. For example, the weather systems differ across Eastern and Western, and Northern and Southern Europe and North Africa. Of course there may occasionally be times, depending on local demand, when there will be little current green energy surplus to trade across the supergrid. That’s where large storage options like hydro reservoir pumped storage and compressed air cavern storage can help (for a few days), pumped up previously using surplus green power. They can supply power locally or via the supergrid to where it is needed. Power can also be generated from stored hydrogen or syngas, these stores being topped up ready for this using gas produced in P2G mode using surplus electricity from renewables previously and run into gas turbines when power is needed. It’s easier to store gas than electricity (and it can be stored for long times) and even better/more efficient to store heat- so flexible CHP /DH plants with heat stores can also help: their power to heat output ratio can be increased to meet power shortfalls and any heat still needed supplied from the heat store, assuming it has been charged earlier when power demand was low. For the moment, most of the gas turbines and CHP plants will run on fossil gas, but gradually they can be converted to run on biogas and low carbon synfuels/P2G, and solar and geothermal heat can also be used to feed the heat stores. This flexible combination of power, heat and gas storage, linked up by supergrids and balanced as far as possible by demand management, expands the smart grid concept so that it should be able to deal with all eventualities. Though that will depend on the economics: some say it will be expensive, others that it will avoid waste, improve balancing and cut costs.
    For a review of advanced balancing options see my book:
    http://iopscience.iop.org/book/978-0-7503-1230-1

    • Greg Kaan says:

      Please read through this previous thread http://euanmearns.com/is-large-scale-energy-storage-dead/ just to quantify the challenges for large storage options.

      Also please look into the pricing of interconnector projects and their capacities to put some perspective into the supergrid notion.

    • donb says:

      “it will be rare for whole continents to be entirely becalmed and cloudy for long periods, so if they are spread widely enough, supergrid interconnectors can often deal with lulls in some parts by trading power from where there is surplus”

      IF each portion of the larger area must have the capacity to supply power to ALL parts of the larger area, then EACH portion must possess the capacity to produce several times the power of what it alone requires. How much more — 5 times, 10 times? That implies installed capacity everywhere far, far beyond what is normally required.

      • Greg Kaan says:

        Also each interconnector need to be scaled to handle the entire demand for the area it feeds since you have no idea which part of the world you will be able to source power from at any time.

      • OpenSourceElectricity says:

        Please provide any proof of this claim.
        Each part must produce a bit more power during the year tahn it consumes, as the conventional capacity in all parts of a grid should be bigger than demand peak(e.g. 30%).
        A reasonable deviation from this basic rule would be -as it often is with conventional pwoer too – that less inhabited areas produce a surplus of power and sell it to densly inhabited areas.
        The same accounts for interconnectors
        People often underestimate the combined interconnector capacities of large areas along its borders. To transfer a power of e.g. 150GW into a area of 1500km diameter, it needs a power line transporting a bit more than 3 GW every 100km. This is not so much more than the existing grid density in central europe.
        Grid extensions in germany mostly happen along the late “iron curtain” which left significant gaps in the grid, which must be closed now.

        • Greg Kaan says:

          Please provide any proof of this claim.

          How about a large high system moving across the Germany/France border at night? No renewable generation in Germany nor in France or Denmark. Norway can only provide for Denmark’s needs so all of Germany’s power must come from Poland. As the high moves westward across the Germany/Poland border, all the power then must come from France

          You can postulate a cop out case of multiple interconnectors from Poland and France, but that’s just equivalent to an extra large interconnector from each of those countries.

          Each part must produce a bit more power during the year tahn it consumes, as the conventional capacity in all parts of a grid should be bigger than demand peak(e.g. 30%).

          This that demand and generations magically correlate at all times. You say my statement needs proof. I’d say yours does,

    • Willem Post says:

      renewstudent,

      Based on your comment, you appear to be officially living in a fantasy world.

      Euan wrote several articles summing all the wind capacity that it likely to exist in Europe (Finland to Spain) by say 2050.

      He applied weather data of past years to the energy production, and found very significant lulls exist multiple times of the year, regardless of the degree of interconnection.

      Some folks want to do away with these evil fossil fuels. What pray tell would supply energy during such lulls to all of Europe?

      BTW, tar is a waste product of refineries. Add aggregate and you have asphalt. No fossil fuels, no asphalt.

      Concrete roads, as in the 1930s? Making concrete is very energy intensive and doing it with wind and solar would be very expensive.

      Would Europe, the US, etc., go back to dirt roads?

      • OpenSourceElectricity says:

        Finland to spain also already shows that the lulls become less frequent and less deep. The studies of supergrids include significant bigger areas, resulting in lulls getting less deep the bigger the areas become. including all europe, north africa and near east results in about no lulls at all.
        Be aware that north africa and e.g. turky already are a part of the european grid, running synchronus.

      • Willem Post says:

        Addition to above comment:

        – If Denmark has a wind lull, it uses Norway/Sweden as a battery.
        – If Finland/Spain has a wind lull, about 400 million people use what as a battery?

  8. Alex says:

    Research shows that consumers are very unwilling to change their behaviour based on micro-signals. Run the washing now and save 5 pence? Can’t be bothered. Sun’s out – put the car on charge? No thanks.

    To actually vary demand significantly, computers need to take over the decisions, and there are two big areas where they can make an impact:
    – Home heating: Given reasonable insulation levels (of the sort we expect on average in 2050) and a high thermal mass, it doesn’t really matter what time of day you apply heat to your house.
    – Car charging: A typical car in 2050 will be plugged in most of the time (when not in use), but only NEED a charge once per week (typical weekly kilometrage is about 100-200km, less than a Chevy Bolt’s range. So the car needs to agree with the grid when it will charge.

    I think given these it would be possible to smooth out daily demand variations, for example, 2050 demand at zero C for the UK could be flattened:
    http://prntscr.com/c602qt

    If we try using the smart grid to match demand to variable output, then we have a much harder task, for example, also at 0C, with one day of highly variable wind power:
    http://prntscr.com/c603fg

    … suggests a need for storage at 230GWh, even before we start to look at storage over multiple days.

    And smart grids don’t help with inter seasonal demand/supply variation, and nor does storage.

    • Joe Public says:

      – Home heating: Given reasonable insulation levels (of the sort we expect on average in 2050) and a high thermal mass, it doesn’t really matter what time of day you apply heat to your house.

      But it will.

      The greatest losses of the well-insulated house are not fabric losses, but ventilation losses.

      The high thermal mass has thermal inertia; the essential ventilation air, and air ingress when doors are opened needs to be heated in real time.

      • Willem Post says:

        Joe,

        Air to air heat exchangers are about 85% efficient.

        Automatic airlocks, a short hall with a door at each end, minimizes heat loss.

        Air changes per hour, ACH, needs to be about 0.5 for good health. Such small quantities can be handled by HEPA filters, to ensure bacteria/pollen-free indoor air.

        Whereas, about 25 – 30 years ago, it was challenging to build PassivHaus buildings, this is no longer the case.

        Almost all NEW buildings could be zero-net energy or energy-surplus, i.e., have enough energy to partially charge one or two EVs.

        • robertok06 says:

          “Almost all NEW buildings could be zero-net energy or energy-surplus, i.e., have enough energy to partially charge one or two EVs.”
          Ah,… I see… you mean a country like Italy would “simply” have to tear down all historic buildings in Florence, Rome, Venice, Naples, etc… etc… ? and rebuild everything like a pagoda-like “passiv house”? 🙂

          It won’t happen any century soon… forget about it.

          • Willem Post says:

            roberto,

            I stated “all NEW buildings”.

            Italy can still use all its old buildings as much as it wants, for whatever purposes.

            No tearing down is required, just a significant tax on heating and cooling to overcome inertia and set a long overdue process in motion.

      • OpenSourceElectricity says:

        A typical massive built house has a thermal capacity of 50-100kWh/K. A typcial thermostate regulation has a accuracy of +/2°K, the good ones +/-1 °K. Losses which you claim must be comensated “atonce” are around 2-4kW in modern built houses (and lower at passiv house lavel). So the “at once” is in the area of several day while remaining within the variability of thermosatat regulation.

      • Alex says:

        This is the heat loss profile for UK homes according to DECC figures:
        http://prntscr.com/c6hx06
        Ventilation is about 25% of heat loss, and this is significantly reduced by installing heat recovery – which all new homes should have,

        An old Victorian house which has been externally clad and sealed would be idea. A huge thermal mass from all the brick works, inside the insulating envelope.

      • gweberbv says:

        Joe,

        air has a very low heat capacity. You must have a very high air flow through the building to lose heat so fast that you notice significant cooling over half a day or so. (Assuming that your house is not exclusively made of materials with low thermal mass -> wood/plastic.)

      • robertok06 says:

        Not to mention that a badly aerated house is prone to develop molds and all kinds of dirty bacteria which have a deleterious effect on the health of the people who live in said houses..

        • Willem Post says:

          roberto,

          No, because internal humidity and temperature are kept within a narrow band.

          HEPA filters eliminate pollen, bacteria and some viruses,

          The insulation must be on the outside of the frame of the house, with a 6 mil PVC barrier., between the frame and insulation.

          Any condensation stays outside the frame of the house.

  9. Jan Ebenholtz says:

    Hi.
    Interesting and educational topic mr Andrew.
    l recomend you all to read Sustainable Energy http://www.withouthotair.com
    Smart grid is in it but the best is ii takes a detailed look at all energy sources and a overall view on what is sensible to connect to the grid. Please read you will find it rewarding. It is for thinking people.
    I will take the opportunity to wish for a topic of Thorium MSR regarding the number of ongoing projects and their timeschedule. A topic over the current problem of licensing new nuclear types would be good.
    Sorry to deviate from the topic.
    Best regards
    Jan Ebenholtz

  10. ristvan says:

    There have been some additional ‘smart microgrid’ experiments. A small island in Denmark, some remote Canadian towns, a university campus in China, a water system in California. All use a combination of ff generation (typically diesel), renewables (wind Denmark, solar China, or both Canada, wind plus hydro in California’s case) and storage in two layers, battery (NaS or NiMH) plus supercaps for reactive power correction (frequency control). All very expensive, and none were able to function standalone for long periods ‘off grid’. I doubt very much that scaleup is more than a green pipe dream.

  11. RegGuheert says:

    I feel that Roger Andrews is being overly dismissive of this topic. Here are some thoughts:

    “I’m not suggesting that anyone tries to interpret what they mean, it’s just that results of this type tell us nothing about how the smart grid is likely to perform under real-life operating conditions – in particular whether it will be capable of filling demand using intermittent generation.”

    Fine. That simple simulation does not say much. But simulation and real-world hardware are very much a chicken-and-egg proposition and always will be. This has been true from the very beginning of simulation when it was first applied to IC design. Even today, chips CANNOT be fully characterized using simulation, but simulation is indispensable in making modern chips possible. The same exact trajectory can be expected with smart-grid: The improvement of advanced simulation tools will enable more advanced smart grid and vice-versa. There will be no step change from where we are today to fully-automated grid interactivity.

    “Grids must contain complex frequency and stability control mechanisms if they are to handle high levels of renewables penetration. Hence some kind of “smart grid” will be needed.”

    Agreed. But I will note that some of the control necessary will come from the renewable components themselves. All inverters connected to the grid in Germany now are required to support various curtailment schemes. But beyond that, having distributed grid-connected inverters has the strong possibility to provide advanced grid control which the utilities have desired for decades. For instance, modern photovoltaic inverters include advanced power-factor correction. Enphase is building these into their products today: http://newsroom.enphase.com/releasedetail.cfm?releaseid=894344

    Unfortunately the Enphase inverters are powered by the PV module, which means they can only provide power-factor correction during the sunlight hours. But modern 3-phase inverters are powered from the AC side and offer power-factor correction capabilities 24 hours per day: http://www.hiqsolar.com/480v-truestring-string-inverter.html

    “Adding these mechanisms, however, is likely to be costly and there is no guarantee that they will work as planned.”

    Almost certainly they will not work as planned. But they will be gradually improved to make them simultaneously more capable and more stable.

    “Even if they do work as planned inadequate storage capacity and intermittency will limit renewables penetration. Regardless of how well the smart grid performs technically there will be extended periods when renewable energy generation plus energy in storage are inadequate to fill demand.
    Backup fossil fuel generation will therefore always be required, although present-day smart grid designs implicitly take this requirement into account. It is in fact difficult to find a smart grid conceptual diagram which does not show a fossil fuel plant as part of the generation mix.”

    None of this is an indictment of smart grid technology. Seasonal storage is the hardest problem to solve, so likely it will be the last addressed. Batteries, pumped hydro and the like do not address the problem of seasonal storage and likely never will. However, they will in the short-to-medium term begin to provide the ability to do things such as extend the reach of PV from sunlight hours to 24 hours, etc. Simply put, smart grid technology can bring high levels of renewable penetration even without providing seasonal storage.

    I’m a big fan of using the batteries of BEVs for the purpose of short-term storage and allowing the consumption and release of energy from the BEV battery to BOTH be charged to the vehicle owner rather than the owner of the electricity fixture. This allows an electronic energy bourse to be created which allows for batteries to provide multiple simultaneous uses and thus improved their value.

    For seasonal storage, you need the energy conversion to be separated from the energy storage in order to minimize costs. Is much as I am not a fan of hydrogen, it DOES have this benefit. One other approach to seasonal storage is to simply provide sufficient PV to address wintertime demands. This particular approach becomes less-and-less workable as you move away from the equator.

    Finally, I will note that there is a significant confluence of technologies which is enabling the implementation of smart grids:

    1: Inexpensive, rugged, high-performance power electronics components. Inverters now offer bi-directional power flow, power factor correction and one-way efficiencies approaching 99%. They are beginning to demonstrate their ability to survive for long periods in the challenging power grid environment.

    2. Low cost renewable generators. PV is both affordable and reliable today.

    3. Affordable, long-life high-efficiency storage. Li-ion batteries now offer ROUND-TRIP energy efficiencies of 98% and life is being extended to very useful levels. Specific energies are increasing at a rate of nearly 10%/year and prices are dropping much faster than that.

    3. Advanced simulation technologies. These exist for other applications today. I suspect the tools specifically for smart grid analysis are somewhat limited today, but that will change as market opportunities arise.

    So, will we have a smart grid tomorrow? No. Will we have one in 20 years? Almost certainly we will.

    • Reg: Thanks for your comment. I’ll just reply to a couple of your observations.

      Seasonal storage is the hardest problem to solve, so likely it will be the last addressed. Batteries, pumped hydro and the like do not address the problem of seasonal storage and likely never will.

      That’s the thrust of my argument. A smart grid may ultimately do everything a smart grid can reasonably be expected to do, but if it can’t smooth out seasonal variations in solar generation and longer-term fluctuations in wind generation then much of the renewable energy fed to it will be non-dispatchable, i.e. largely unusable for load-following purposes. The only solution is to retain enough dispatchable capacity (gas, coal, nuclear) to fill demand when the wind doesn’t blow and/or the sun doesn’t shine and to waste renewable energy when they do. More detailed information in these (and other) posts:

      http://euanmearns.com/estimating-storage-requirements-at-high-levels-of-wind-penetration/
      http://euanmearns.com/hinkley-point-c-or-solar-which-is-cheaper/

      A specific example of how a smart grid is of no help under these circumstances is the Gorona del Viento wind-pumped hydro-smart grid plant on the Canary island of El Hierro, which because of inadequate pumped hydro storage experiences long periods of minimal generation when the wind doesn’t blow and which the smart grid is unable to do anything about. The results are exhaustively documented in the El Hierro portal http://euanmearns.com/el-hierro-portal/.

      One other approach to seasonal storage is to simply provide sufficient PV to address wintertime demands. This particular approach becomes less-and-less workable as you move away from the equator.

      Already evaluated: http://euanmearns.com/a-potential-solution-to-the-problem-of-storing-solar-energy-dont-store-it/

      • RegGuheert says:

        “Already evaluated:”

        So you have! Nice post. I live at 40 degrees North latitude and your numbers match my production quite well.

        But I have to say that as you move away from the equator, the problem gets much worse much faster than you indicated in your post. The reason is that if you heat with electricity like I do (efficient heat pump), the load in December and January is TRIPLE what it is in June and July.

        The simple result is that in order to cover my ACTUAL usage in December and January I would have to triple or quadruple the size of my current array which currently covers my needs through the magic of net metering.

        • Greg Kaan says:

          “the magic ofsubsidies through net metering.”

        • Willem Post says:

          Reg,

          Net metering and subsidies are the crutches of solar energy.

          Without those two, it would be in a wheelchair.

          • RegGuheert says:

            Feel free to name all the sources of electricity that we use which are NOT subsidized. If I am not mistaken, they ALL are currently susidized and also ALL had higher subsidies early in their lives (at least here in the US).

            It absolutely is a crutch but IMO, this particular approach to enabling the growth of an outstanding energy technology is quite a nice compromise. That said, this is only true at low penetration levels of PV. The discussion becomes much more difficult in places like Germany where sunlight is rare (during significant parts of the year) and penetration levels are now much higher.

            Ultimately, we need to solve the bigger issues of both short-term and seasonal storage. High-efficiency, short-term (days) storage solutions are available today for about US$0.20/kWh or less. At that price, they will likely be quickly embraced in some locations (like Hawaii and parts of Australia) but will not currently be interesting elsewhere.

            For my situation, the seasonal side of the storage solution could be had by approximately tripling the size of the PV array. Since I can build PV for about US$0.05/kWh, I can address the seasonal side of the issue for US$0.15/kWh.

            That would bring my entire cost for the system to about US$0.35/kWh. That’s not attractive where I live today since electricity costs US$0.12/kWh.

            But in Hawaii where electricity costs US$0.35 already and the entire system with storage can be had for US$0.30 (less seasonal requirement due to latitude) the oversized PV/LI-ion battery solution is ALREADY less expensive than grid electricity.

            Given that the costs of both PV and batteries are coming down while grid electricity is going up, it seems clear that there will eventually be a crossover in many, if not all, markets, even at the level of individual consumers.

            IMO, the real questions are not whether PV makes sense or not. The real questions are WHERE does it make sense today and WHEN it will make sense in other locations, if ever, and how do we handle the transition when it does become viable. Finally, what does the optimal “end” solution look like.

            That’s one thing I appreciate about the work that Roger and Euan have been doing at this blog. They have been working out the details around many of these questions.

          • robertok06 says:

            @RegGuheert

            “Feel free to name all the sources of electricity that we use which are NOT subsidized.”

            Nuclear in France.
            It not only covers, largely, its costs, but it even covers the cost of PV and wind.

          • robertok06 says:

            @RegGueerth

            “Since I can build PV for about US$0.05/kWh, ”

            Nice!… how’s life on Venus?

            Beware of the troll!

        • @Reg

          So you are saying that you can build a 4kWp domestic PV array for $350?

          • RegGuheert says:

            No. Look carefully at the units in my post. The prices are all in US$/kWh.

          • Willem Post says:

            donoughshanahan/Reg

            Here is a reality check, based on actual numbers.

            Rooftop PV averages about $4000/kW in New England in the US.

            During its 25-y life, a fixed axis, 5 kW roof system would produce a maximum of about 5 x 8760 x 0.15 x 25 = 164,250 kWh .

            Ignoring O&M and replacements, no degradation, no dust, no snow and ice, perfectly facing south at the right angle, and zero salvage value, and zero cost of money, and zero profit, etc., the energy cost would be about $20000/164250 = 12.2 c/kWh.

            Ignoring nothing, it would be at least 20 c/kWh

            At about 40% state and federal, up-front, cash subsidies, it would be about 12 c/kWh.

            In Vermont, grid-connected owners receive about 19 c/kWh for their surplus energy sold to a utility.

            About 75% of the hours of the year, the PV energy would be minimal or zero.

            With many PV systems on a distribution grid, the output variation during daylight hours (variable cloudiness) would disturb those grids, unless they have battery damping/storage, as is being implemented in southern Germany and southern California. The cost of that storage is “socialized”.

            The production ratio of MONTHLY maximum summer/MONTHLY minimum winter is about 4, based on data from numerous existing PV systems in NE.

            The DAILY ratio is about 25.

            See my above comment regarding 50 nuclear reactors.

          • RegGuheert says:

            @Willem Post

            “Rooftop PV averages about $4000/kW in New England in the US.”

            I don’t doubt it. But the installed cost of commercial PV worldwide now sits around $115/Wp: http://www.pv-tech.org/news/pv-cost-decreases-to-ensure-strong-demand-in-2016-and-beyond-energytrend

            According to that article, they calculate LCOE to be US$0.07 today for utility-scale PV and US$0.06 tomorrow.

            As far as for home use, I can purchase a complete system today for about $1.50/Wp COMPLETELY UNSUBSIDIZED with a 25-year warranty on the PV and the inverters. If I install it myself, that is my cost. Otherwise, I can pay more to have someone else install it.

            “During its 25-y life, a fixed axis, 5 kW roof system would produce a maximum of about 5 x 8760 x 0.15 x 25 = 164,250 kWh.”

            In New England. My 12.75kW system in VA produces 18MWh each year. Over a 25-year life, that comes to 450 MWh. (Conservative figure, since the equipment is GUARANTEED for 25 years. It is not likely to drop dead the day after the warranty expires.)

            That comes to US$0.0425/kWh for a DIU home project if I ignore both the issues you mention and the extra life I mention.

            “The production ratio of MONTHLY maximum summer/MONTHLY minimum winter is about 4, based on data from numerous existing PV systems in NE.”

            That’s exactly right and was one of the points in my first post. As mentioned above, the problem with PV in New England is MUCH worse since your maximum load is also MUCH higher than the minimum load and this maximum corresponds with the minimum PV production. The bottom line is that you might need to install 10X the amount of PV to achieve a seasonal result. Even then it would be very iffy since snow loads in February can stop production.

            Bottom line, PV makes little sense in places like New England and Germany.

            But let’s not paint the whole world with the same brush. As you approach the equator, there are many areas where PV makes excellent sense TODAY.

            IMO, net metering is a good compromise today which allows for a (very slight) reduction in the number of mountains leveled and valleys filled in WV to extract coal while allowing the PV market to develop.

          • RegGuheert says:

            DIU -> DIY. 😉

          • @ Reg

            4kWp at 22% capacity factor for Hawaii is 4*8760*.22 = 7709 kWh

            “Since I can build PV for about US$0.05/kWh”

            =7709*.05 = $385

            I am not questioning the add on for storage opr anything else.

          • RegGuheert says:

            @ donoughshanahan

            You have left out a factor of 25 years. Here is the proper equation:

            4 kWp * 0.22 CF * 24 hours/day * 356 days/year * 25 years = 192,720 kWh over the life of the equipment

            192,720 kWh * US$0.05/kWh = $9630 for a 4 kWp system

            I would normally say that is a bit high, but I know things are more expensive in Hawaii. PV is extremely popular in Hawaii since paying US$0.05/kWh with net metering is a HUGE savings when compared with $0.41/kWh from the utility. And that is TODAY’s price for grid electricity. Imagine what the average price for grid electricity will be over the next 25 years!

            Because of this, they are starting to struggle with grid instability. As such, they need to start contending with storage. At the current grid prices, battery storage is affordable in Hawaii.

          • robertok06 says:

            @RegGueerth

            “I don’t doubt it. But the installed cost of commercial PV worldwide now sits around $115/Wp”

            115 dollars per Wp… and kWh at 5 cents?… would need a capacity factor around 800%, at least.

            Warning: troll crossing the road… a protected specie.

          • robertok06 says:

            @RegGueerth

            “Here is the proper equation:”

            yes… the proper equation in fantasy-land…

            Sorry, this is BS at its purest form: according to NREL’s LCOE calculator, even at 1 dollar/Wp, with 5% interest, and 22% capacity factor, the cost of 1 kWh over 20 years is at least 6,7 c$… what the hell are you talking about????

          • regguheert says:

            @robertok06

            “115 dollars per Wp… and kWh at 5 cents?… would need a capacity factor around 800%, at least.”

            Clearly that was a typo.

            “Warning: troll crossing the road… a protected specie.”

            You should consider learning some manners.

            “Sorry, this is BS at its purest form: according to NREL’s LCOE calculator, even at 1 dollar/Wp, with 5% interest, and 22% capacity factor, the cost of 1 kWh over 20 years is at least 6,7 c$… what the hell are you talking about????”

            You can put whatever numbers in that calculator you like to try to make any point you want. But I chose to use realistic numbers.

            Using the default discount rate of 3% (which is still probably high) and use 25 years, which is the GUARANTEED life of both the PV and the inverters.

            LCOE at US$1.5/Wp = US$0.044/kWh

            Maintenance MIGHT bring it up to US$0.05/kWh.

            That’s what I’m talking about.

            Moreover, I don’t think LCOE is a useful concept for a homeowner considering PV. Why? Because the price homeowners pay for electricity will certainly rise at an unknown rate going forward. As such, it is best to simply apply a 0% rate over the period in order to make a fair comparison with the price being paid for electricity today.

            For others, here is the link to the NREL LCOE calculator:

            http://www.nrel.gov/analysis/tech_lcoe.html

          • @ reg

            Oops. My bad. Ta

    • robertok06 says:

      “The same exact trajectory can be expected with smart-grid:”

      Not at all!… a silicon chip generation lasts few years, a new electric network at the level/size of a whole continent takes decades upon decades to be done and redone.
      Your comparison is silly at best.

      Nice try though.

    • robertok06 says:

      “Li-ion batteries now offer ROUND-TRIP energy efficiencies of 98% and life is being extended to very useful levels.”

      sorry, byt this is BS until proven true (with at least one peer-reviewed paper).

      98% over how many cicles? 98%over what kind/level of discharge? Deep discharge? 30%… c’mon… you are asking mother nature something she’s not capable of deliver, do you understand that?

      R.

      • Willem Post says:

        roberto,

        Even Musk of TESLA would not claim such an idiocy. His own engineers would laugh him out of the room.

        Here is an article on batteries, which is based on the real world. It includes TESLA’s world.

        http://www.theenergycollective.com/willem-post/2308156/economics-of-batteries-for-stabilizing-and-storage-on-distribution-grids

        • Willem Post says:

          Addition to above comment:

          Most articles on batteries, as applied to electric grids, often written by non-technical people, are not based on real world data. As a result, unfounded optimism is spread regarding the economics of battery systems and their near-term implementation.

          This article is based on the real-world, operating limitations of the Chevy-Volt and TESLA lithium-ion batteries, and the TESLA powerwall specification sheet data, to determine battery losses, operating limits and energy storage costs, c/kWh, of the battery systems attached to distribution grids. Without the real world data as a basis, erroneous conclusions would have been the result.

          Chevy-Volt: The 2014 Chevy-Volt has a 16.5 kWh battery, but it uses a maximum of about 10.8 kWh (about 65% of its capacity, a slightly greater % on subsequent models), because the battery controls are set to charge to about 90% and discharge to about 25% of rated capacity. The 10.8 kWh gives the Chevy-Volt an electric range of about 38 miles on a normal day, say about 70 F, less on colder and warmer days, less as the battery ages.

          TESLA Model S: The TESLA Model S uses 75.9 kWh of its 85 kWh battery for rare, extremely long trips, so called “range driving”, 75.9/85 = 89% of rated capacity, and uses 67.4 kWh for maximum “normal driving” discharges, or 67.4/85 = 79% of rated capacity. Almost all people use much less than maximum “normal driving” range, because they take short trips and charge their vehicles on a daily basis, thereby preserving battery life.
          https://forums.teslamotors.com/fr_CH/forum/forums/rated-range-85-kwh-battery

    • Beamspot says:

      Many of your assumptions on Li batteries are plain wrong. High capacity cells like those used by Tesla in their model S last only 600 – 700 100%DoD cycles, not more.

      After burning more than one hundrer Li ion and Li pol batteries myself, even under different climatic conditions, I’m pretty sure (and few colleages in the BEV R+D dept confirm that to me) no Li chemistry batteries stand for more than 2000 100% DoD, and not to mention that >80% of those cells last more than 10 years.

      98% round trip is under optimal low load laboratory conditions, and only stands for the energy/in/energy out of the battery, not for the whole system that is in real life <90% if not in the low 80% range. Raising efficiency will rise quite a lot the price and cost.

      Price drop during the last years was due ONLY to the drop in price of commodities. My calculations on costs of raw materials reached the bottom by the end of 2015, and since then few elements dropped very few, while others increased the cost by quite much. Take a look of the evolution of the price of battery grade lithium. From roughly 6000€ ton to 14000€ ton within few months.

      I bet that costs of battery cells (not battery packs, that is a different story) reached a bottom, and probably their cost will rise for next years.

      Capacity is also close to the theoretical maximum possible. The specs by 2012 were that the limit would sit about 30% more that they had back then, but the life span gets seriously compromised, safety as well, so now, BEV developers expect that specific capacity hardly can increase less than 10% of the actual, and only if graphene can be used.

      And Graphenano is an scam.

      And you also forget the aging and life of electronics, that matters much more than anybody thinks, and it is never ever mentioned (except by Pedro Prieto Pérez, but he is an insider with real life experience, and that is something that the theorist of PV supermacy hate more than anything else, since this is high treason).

      Switching matters, BEV propietaries wouldn't allow the grid to use the energy stored into their tiny and ultra expensive batteries: perhaps they couldn't commute the next day. I've raised that question few times, and the usual response is that once the carge is complete, they will disconnect the car, just in case.

      It makes no sense to pay for an expensive and aging infrastructure (your car BEV) that is being used by others preventing you to user your own, unless you get very well paid for that. And that means about 1€/KWh extracted from your batteries.

      ESOI calculations checked by me showed that many of them had been done based on totally wrong assumptions. When re-do by me with real life data, it shows that any Li battery storage will cost a bare minimum of 0.5€ for each KWh you extract from them, only as battery aging, not to mention the remaining issues (cost of the 1.15 KWh you put it in before, aging of electronics and other ancilliary systems, CAPEX and such).

      That shows the regular trick by PV green dreamers: hide as many related costs as possible, otherwise the dream becames a nightmare that nobody wants to pay.

      If you think that PV and wind turbines, together with batteries will do the trick, then be and example and unplug yourself from the grid: I don't want to pay the costs of your intermitencies and related problems.

      • Beamspot says:

        Ehm, I’m wrong. I mean that <80% of battery cells will never last more than 10 years, even at low temperatures (at higher temperatures, Arrhenius implies shorter lifespans, about 5 years south of the Pirenees, less than 1 year in Saudi Arabia).

        Very few chemestries have long life and high number of cycles. So few that I don't know their existence (maybe some of Edison's variants?), and in any case, the efficiency, specific energy and cost are issues.

        There are also other limitations.

        http://energyskeptic.com/2016/only-sodium-sulfur-batteries-have-enough-material-on-earth-to-scale-up/
        http://energyskeptic.com/2016/not-enough-lithium-for-electric-car-batteries/
        http://energyskeptic.com/2015/making-the-most-energy-dense-battery-from-the-palette-of-the-periodic-table/

      • RegGuheert says:

        “Many of your assumptions on Li batteries are plain wrong.”

        No, they are not assumptions and they are not wrong. Here are the details.

        “High capacity cells like those used by Tesla in their model S last only 600 – 700 100%DoD cycles, not more.”

        True. But you do not seem to be aware of the advances in technology which have been made since then. I’ll start by posting this video by the inventor of the next-generation BEV batteries, Dr. Jeff Dahn:

        https://youtu.be/pxP0Cu00sZs

        Unfortunately,Dr. Dahn is an excessively boring speaker but he details a new testing method which allows life testing in two weeks. Using this, he is able to evaluate electrolyte additives to determine which is best. One combination they have tested extended the life of the batteries by 20X! Last year Tesla engaged with Dr. Dahn to get access to his approaches:

        http://www.powerpulse.net/story.php?storyID=32461;s=061820151

        “After burning more than one hundrer Li ion and Li pol batteries myself, even under different climatic conditions, I’m pretty sure (and few colleages in the BEV R+D dept confirm that to me) no Li chemistry batteries stand for more than 2000 100% DoD, and not to mention that >80% of those cells last more than 10 years.”

        Here’s one which is available today which is GUARANTEED to deliver 7300 95% discharges:

        https://enphase.com/en-us/products-and-services/storage

        “98% round trip is under optimal low load laboratory conditions, and only stands for the energy/in/energy out of the battery, not for the whole system that is in real life <90% if not in the low 80% range. Raising efficiency will rise quite a lot the price and cost."

        You are correct that is at the battery only. Including the conversion electronics, the efficiency is above 90%, not below, even for a small battery and single-phase power converter. See the link above. However, the efficiency number I provided IS at normal operating powers. See page 9 below for testing from a 6-year-old BEV battery:

        https://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2012/veh_sys_sim/vss030_lohsebusch_2012_o.pdf

        "Price drop during the last years was due ONLY to the drop in price of commodities. My calculations on costs of raw materials reached the bottom by the end of 2015, and since then few elements dropped very few, while others increased the cost by quite much. Take a look of the evolution of the price of battery grade lithium. From roughly 6000€ ton to 14000€ ton within few months."

        Yet BEVs with 60 kWh batteries cost the same as BEVs with 24 kWh batteries 6 years earlier.

        "Capacity is also close to the theoretical maximum possible. The specs by 2012 were that the limit would sit about 30% more that they had back then, but the life span gets seriously compromised, safety as well, so now, BEV developers expect that specific capacity hardly can increase less than 10% of the actual, and only if graphene can be used."

        The new 60-kWh BEVs use NMC Li-ion technology, which provides both more capacity and better safety than the previous generation. Interestingly, Dr. Dahn (mentioned above) is also the inverter of the NMC Li-ion chemistry. Battery University has some nice spider diagrams:

        http://batteryuniversity.com/learn/article/types_of_lithium_ion

        The batteries in the new 60-kWh BEVs is "good enough" for most personal transportation needs, so further capacity improvements are not overly critical. Capacity is not an important FOM for stationary applications.

        "And you also forget the aging and life of electronics, that matters much more than anybody thinks, and it is never ever mentioned (except by Pedro Prieto Pérez, but he is an insider with real life experience, and that is something that the theorist of PV supermacy hate more than anything else, since this is high treason)."

        No, I haven't forgotten that at all. In fact, I am tracking the actual life of thousands of PV microinverters which are operating on the roof:

        https://docs.google.com/spreadsheets/d/1zCMhT5S-uQrT676yrTL4NjEyI1BOWWOGZh7iqhrH7II/edit#gid=0

        The third-generation inverters suffered from a poor MTBF, but the fourth-generation units are showing an MTBF of 460 years. (This may be a bit low, since it appears that the first batch of fourth-generation units appear to have included third-generation electronics.) In any case, microinverters operated on the roof are GUARANTEED for 25 years in a harsh roof environment. Electronics used with batteries are not exposed to such an environment.

        "Switching matters, BEV propietaries wouldn't allow the grid to use the energy stored into their tiny and ultra expensive batteries: perhaps they couldn't commute the next day. I've raised that question few times, and the usual response is that once the carge is complete, they will disconnect the car, just in case."

        The 60-kWh batteries in the BEVs shipping this fall store a week's worth of commuting energy. To meet the needs as I am discussing, they will need to be plugged in both at work and at home, charging at work and providing electricity at night. Future generation BEVs will be even more capable.

        "It makes no sense to pay for an expensive and aging infrastructure (your car BEV) that is being used by others preventing you to user your own, unless you get very well paid for that. And that means about 1€/KWh extracted from your batteries.

        ESOI calculations checked by me showed that many of them had been done based on totally wrong assumptions. When re-do by me with real life data, it shows that any Li battery storage will cost a bare minimum of 0.5€ for each KWh you extract from them, only as battery aging, not to mention the remaining issues (cost of the 1.15 KWh you put it in before, aging of electronics and other ancilliary systems, CAPEX and such)."

        That all depends on the life of the battery, which is being significantly extended using new approaches. It seems you have used assumptions based on previous-generation technology. As I have shown, the durability of these batteries is being extended significantly as time goes on. Once battery capacity fade is mostly eliminated, there will be no concerns here. On top of that, as more-and-more PV generation on the grid is added, the value of providing a load during the day and a source at night will be very high.

        "That shows the regular trick by PV green dreamers: hide as many related costs as possible, otherwise the dream becames a nightmare that nobody wants to pay."

        No trick. It is you who are using made a bunch of unsupported assumptions based on outdated assumptions. Li-ion technology is advancing extremely quickly and I am basing all of this on existing and emerging technology.

        "If you think that PV and wind turbines, together with batteries will do the trick, then be and example and unplug yourself from the grid: I don't want to pay the costs of your intermitencies and related problems."

        Perhaps you didn't read my post?? I am a fan of net metering for today and I detailed the real issues regarding season storage, where Li-ion battery do not play. I was clear on this point. But overnight storage with Li-ion battery is becoming a reality today in near-the-equator locations where electricity is expensive.

        • Beamspot. says:

          I didn’t find wher the >7000 @95% DoD is warranted at all in the link you give. Certainly it mentions more than 7000 cycles, but it doesn’t mention at wich DoD.

          Those are Ferrophosfate batteries, the ones that last longer, the safer, and also the heaviest (except LiTi, that IMHO is not a li battery like the others, as I have also my doubts with LiFePO).

          There are two tricks about that: not to mention the DoD for the given cycles, as in that case. But there is another one: About 2000 cycles @100% DoD. If you sell a whole pack with, say, four times the spec’ed capacity (I mean you sell a 1KWh pack but in fact it is like a 3.6KWh real, but electronically capped), then you have a 8000 cycle 100%DoD, as per spec, but is will also be like 3 times more expensive.

          This is the usual trick used nowadays with battery packs. Been there, done that.

          NMC variant had been there for a while, and in the same link you provide, Mr. Buchanan (IIRC) states the same rough figures I gave, not the ones you mention.

          Can you provide a link where those bold claims are clearly stated, with that 20x life improvement? Can you also give some figures about how the temperature affects battery life? (something like http://www.electricvehiclewiki.com/Battery_Capacity_Loss )

          The efficiency of the Leaf that you linked, an old known picture I used back in 2012 in my courses for EV’s at my automotive plant, stated 86% or so efficiency, 97% the battery alone, but in test mode (rulers, into a climatically controlled chamber), and by Li-pol batteries, high power ones, that are the ones that serious car manufacturers use (no, I don’t like Nissan Leaf).

          Do you really believe that Model 3 will give you 60KWh at 35000$? Certainly I believe that cost per KWh of the Tesla car will be much better than that of the Leaf, but I wouldn’t expect such energy, and even less such price. Something like 45KWh at 45.000$ is more akin to what I think it will be… at a loss (like happens with all other cars sold by anyone, being it Musk or Nissan).

          I’ve asked many people about the upload electricity to the grid, and the majority (that work in the automotive industry, BTW), don’t like the idea by far. This is not about technical feasibility, but about economy.

          Regarding the inverters at 460 years, I guess you would mean 46 years instead, but AFAIK (and this is my bread and butter) no semiconductor is spec’ed at more than 100.000 hours (less than 15 years) in very ideal conditions (in real ones, y guess about 50.000). And inverters not only use semiconductors (both controllers and power ones) but also electrolityc capacitors (the tipical element that signals the end of life of all electronic products). So, if you have some link to such wild and bold claims, I will be really glad to analyze it thouroughly, because it seems it is a scam (like Graphenano).

          BTW, may oudated assumptions are not assumptions, are the results of my work at a lab, developing commercial products that you can buy right now, and that include Li batteries, as well as NiMH and Pb.

          And also are claims from my previous position as R+D engineer in the HEV division of a known european automotive company, developing inverters and battery packs. I leave by 2012 back to my previous plant, where I still work, just before the company begins the restructuring of the department after losing more than 1000€M in HEV products like Renault Fluence, Twizzy, Zoe, Audi Q7 hybrid, and many more. I still have some colleagues working there, in the ‘new wave’, as well as other colleagues that moved to competitors, and all of them (last week) agree with my coments.

          So, certainly, mine are ‘outdated’ assumptions based on my first-hand, and not sou ‘outdate assumptions’ second-hand.

          The data I gave is consistent with battery university, as well as many other sources, that usually are discarded for being pessimistic (for me data is data, and that is the ground of my ideas, not links or datasheets that I found misleading quite often, specially those of batteries).

          So, I beg your pardon if I don’t switch my mentality and keep believing what other sources, starting with my own data and more trustworthy (to me) sources gave me.

          Thus I keep saying that use your own example, buy a battery pack, and sell the electricity when it is expensive, and store it when cheap, take pictures by yourself, give numbers, statistics, etc, This is the best thing you can use to convince people. Wild claims based on links and such, whithou any clear data and statement, whitepaper, flyiers and such commercial advertising is anything but trustworthy, and for my colleagues and close friends, it is even a reason for suspicion.

          • RegGuheert says:

            “I didn’t find wher the >7000 @95% DoD is warranted at all in the link you give. Certainly it mentions more than 7000 cycles, but it doesn’t mention at wich DoD.”

            The DOD spec is right on the link I provided: Here it is since you didn’t find it: “-Most usable capacity (>95% D.O.D.)”

            “This is the usual trick used nowadays with battery packs. Been there, done that.”

            Clearly, you haven’t seen this technology before and your information is outdated. Don’t believe the specs from Enphase? Here’s the link to the datasheet for the battery manufacturer’s page:

            http://eliiypower.co.jp/english/technology/index.html

            From the website:
            “What’s more, they offer an extended lifespan: even if charged and recharged repeatedly for 10 years (approx. 12,000 times), they will retain 80.1%* of their electricity storage capacity.
            You may therefore use our products safely over long periods of time. *Estimated value assuming 23ºC room temperature and three full charge and recharge cycles per day (depth of discharge (DOD) = 100%).”

            Let’s see, there’s is a battery with 6X the cycle life of what you claim is possible:

            “Can you provide a link where those bold claims are clearly stated, with that 20x life improvement?”

            I already did. Here it is again:

            https://youtu.be/pxP0Cu00sZs

            What the movie and learn. I don’t know who owns that chemistry, but the point is that this issue is being solved quickly through clever engineering.

            “The efficiency of the Leaf that you linked, an old known picture I used back in 2012 in my courses for EV’s at my automotive plant, stated 86% or so efficiency, 97% the battery alone, but in test mode (rulers, into a climatically controlled chamber), and by Li-pol batteries, high power ones, that are the ones that serious car manufacturers use (no, I don’t like Nissan Leaf).”

            That’s right. The 6-year-old battery technology in the Nissan LEAF has 97% RT efficiency. Today’s EVs have batteries with 98% RT efficiency, just as I stated.

            Yes the charger in the LEAF is particularly inefficient. But again, things have changed You can purchase single-phase inverters today which achieve an efficiency of 99% using inexpensive semiconductor technologies:

            http://www.solaredge.com/products/pv-inverter/hd-wave

            The point is that the losses in the conversion electronics is quickly becoming vanishingly small. Even with the electronics included, RT losses will be above 95% in the very near future.

            And, no, that LEAF test was not done “under optimal low load laboratory conditions” as you originally stated, but on a dynamometer in a simulated driving test.

            :”Do you really believe that Model 3 will give you 60KWh at 35000$?”

            No. Who said anything about a Tesla Model 3? No, I’m talking about the Chevy Bolt, which will be shipping any day now with a 60 kWh battery for $35,000.

            “I’ve asked many people about the upload electricity to the grid, and the majority (that work in the automotive industry, BTW), don’t like the idea by far. This is not about technical feasibility, but about economy.”

            The ONLY major barrier is battery durability. As I have pointed out, that is being solved.

            “Regarding the inverters at 460 years, I guess you would mean 46 years instead,…”

            Nope. I meant what I said: “…the fourth-generation units are showing an MTBF of 460 years.” Since you do not seem to know what MTBF is, here is a primer for you:

            https://www2.enphase.com/wp-uploads/enphase.com/2011/03/Enphase_WhitePaper_Reliability_of_Enphase_Micro-inverters.pdf

            “So, certainly, mine are ‘outdated’ assumptions based on my first-hand, and not sou ‘outdate assumptions’ second-hand.”

            If your information is not outdated, then how come there are products shipping in the market that *directly* contradict your claims? Your knowledge will remain outdated if you are unable to integrate new developments.

            “Thus I keep saying that use your own example, buy a battery pack, and sell the electricity when it is expensive, and store it when cheap, take pictures by yourself, give numbers, statistics, etc, This is the best thing you can use to convince people. Wild claims based on links and such, whithou any clear data and statement, whitepaper, flyiers and such commercial advertising is anything but trustworthy, and for my colleagues and close friends, it is even a reason for suspicion.”

            Again, it seems you did not read what I wrote in the post you originally responded to:

            “Seasonal storage is the hardest problem to solve, so likely it will be the last addressed. Batteries, pumped hydro and the like do not address the problem of seasonal storage and likely never will.”

            …and then in another post I wrote…

            “For my situation, the seasonal side of the storage solution could be had by approximately tripling the size of the PV array. Since I can build PV for about US$0.05/kWh, I can address the seasonal side of the issue for US$0.15/kWh.

            That would bring my entire cost for the system to about US$0.35/kWh. That’s not attractive where I live today since electricity costs US$0.12/kWh.”

            But, as I pointed out elsewhere, the current battery technology addresses the problem of nightly storage in applications near the equator where electricity is expensive, such as Hawaii.

      • Beamspot

        What would a grid scale battery pack look like anyway? Would there be some safety concerns with a pack that big?

        • RegGuheert says:

          Here’s the page for the grid battery from Tesla:

          https://www.tesla.com/powerpack

          • Not what I would call grid scale……

          • RegGuheert says:

            From the website: “The Powerpack system scales to the space, power and energy requirements of any site, from small commercial businesses to regional utilities. It can be configured in various arrangements, offering far more modularity than competing models.”

            That said, I don’t know if this approach will be cost competitive with other grid-connected battery systems at large sizes.

          • Greg Kaan says:

            I am sceptical of any claims made by Tesla on any subject. The stock market manipulations by the CEO seems to know no bounds so the company has zero credibility.

  12. gweberbv says:

    By the way: When looking at the German demand curve one gets the impression that on days with a lot of renewables production demand is also higher by a few GW compared to days with much less PV and wind production. Maybe these are already first signs of flexible demand responding to supply.

    • gweberbv says:

      I should add that from first principles you would expect the opposite dependency: less PV -> more demand (because self-consumption lowers the visible demand)

      • robertok06 says:

        Your equation doesn’t hold water, Guenter!
        PV generates independently of demand… it generates more when people demand less electricity… but not because of self-consumption, which is around 30% in Germany.

    • Hugh Sharman says:

      @ gweberbv, can you kindly supply some statistcs for this. If true, of course, it could, just, be possible that the “Hallelujah” advocates for DM control are onto something. I somehow doubt it. During an “interview” meeting at Denmark’s Energinet.dk in 2014, ENDK’s representative was derisive of past attempts to alter the country’s demand pattern to any significant degree.

      • gweberbv says:

        Hugh,

        unfortunately, I can provide you only with anecdotal evidence from looking at the data of Agora Energiewende (see the link on the right side of this webpage).
        Here is a screenshort of the first two weeks in July: http://www.directupload.net/file/d/4449/xqvknzpb_jpg.htm
        (I removed the weekends which have a much lower demand than the working days.)
        For the working days you find a correlation between between domestic consumption (red line) and PV+wind production.

        • Hugh Sharman says:

          Hmmmm….Thanks for drawing my/our attention to this. On the face of it, your speculation appears to have “legs”! Enough, I think for our asteemed friend Roger to investigate more closely. Why not ask Agora Energiewende, the source of this data, to comment directly?

          They are, after all, the ultimate “Hallelujah” proponents of the Energiwende?

          • The demand pattern is not too dissimilar to what I posted. They are similarly doing a better job than in say 2100 of using solar to fill in the gap.

            However you need to understand exports as well to see how well they are doing.

          • robertok06 says:

            “However you need to understand exports as well to see how well they are doing.”

            Ths situation in Germany is very bad… for PV I mean. During the last auction they had a hard time covering all of the offered MWh… and the best price, in spite of the “very low cost of PV” has been more than 12 cEuro/kWh… i.e. almost 5 times the value of the kWh on the market (basically as low as 2.5 cEuro)… and this without considering the “externalities” due to intermittency and seasonality.
            What a success! CLAP! CLAP!… let’s all copy the mithical Energiewende!… presto!

          • gweberbv says:

            Roberto,

            you can do it better, I hope.

            1st PV auction: May 2015, 92 Euros/MWh, ‘oversubscribed many times’ for a slot of 150 MW
            -> http://www.pv-magazine.com/news/details/beitrag/germany–first-pv-tender-round-closed_100019536/

            3rd PV auction: December 2015, 80 Euros/MWh, 562 MW bids for a slot of 200 MW
            -> http://www.pv-tech.org/news/germanys-third-solar-auction-sees-prices-lower-again

            5th PV auction: August 2016, 72 Euros/MWh, 311 MW bids for a slot of 125 MW
            -> http://www.pv-magazine.com/news/details/beitrag/germanys-fifth-solar-auction-allocates-130-mw-to-25-projects_100025687

            The (roughly) 120 Euros/MWh you are referring to is the feed-in tariff for small-scale installations.

          • robertok06 says:

            I take back what I wrote in my previous message… as explained here…

            http://www.germanenergyblog.de/?p=18520

            .. the auction was OVERsubscribed by a factor of 4… and the average cost was a bit more than 9 cEuro/kWh, not 12… but anyway…

            “Bidders have two years to apply for a certificate of support in the amount of their bids, which requires installation of the PV plants by that time (cf. Section 20 para. 2 sent. 1 in connection with Section 22 para. 1 no. 1 FFAV).

            It is noteworthy that they will receive financial support as awarded while support for other PV installations declines on a monthly basis (for more information, please see here).

            Bidders have thus locked in financial support that is higher than financial support currently paid under the EEG 2014 for a period of two years, while the aim of auctioning was actually to make support more cost-effective. ”

            So, to summarize… the aiim of the auctioning was to reduce support, but in the end if worked the other way around, increasing it: mithical Energiewende!… coming to a theater near you. 🙂

        • robertok06 says:

          “For the working days you find a correlation between between domestic consumption (red line) and PV+wind production.”

          Nonsense. Your red line is “electricity consumption”, not “domestic consumption”… domestic consumption in germany is around 25% of the total consumption, like in most countries which are not heavily electrified (Norway, France).

      • OpenSourceElectricity says:

        I do not have any statistic of this, but I observed the same at agorameter. Whenever there is high EE suply, demand must be corrected several GW upwards when it is changed fro prognosis to measured levels.
        Since we are already two who observerd this behaviour in this discussion alone, somebody else will see this (new) behaviour too and produce some study about it as I expect.

      • Hugh

        Demand for Germany; it is estimated using the pfback website. Germany and France have a “fairly” flat profile from 8am to 9pm so there could be something going on but I have seen no evidence.

        https://carboncounter.wordpress.com/2014/09/29/when-does-electricity-demand-peak/

        • sod says:

          “Demand for Germany; it is estimated using the pfback website. Germany and France have a “fairly” flat profile from 8am to 9pm so there could be something going on but I have seen no evidence. ”

          I think you are talking about this picture:

          https://carboncounter.files.wordpress.com/2014/09/peak1.jpeg?w=1058

          But the problem is, that current output already is demand minus solar PV.

          So i think that Agora is giving a much better picture:

          https://www.agora-energiewende.de/de/themen/-agothem-/Produkt/produkt/76/Agorameter/

          • Maybe. I was just opening the possibility of a flat use during the day leaving the possibility of demand management.

            Also by Agora, the peak is much less in winter…

            “But the problem is, that current output already is demand minus solar PV.”

            I am not sure if that is a valid basis. you could assume that all LV generated solar gets used, unless there is a lot on the LV grid. Even so it implies a management issue of electricity flow to me as opposed to demand management compensating…

    • robertok06 says:

      “Maybe these are already first signs of flexible demand responding to supply.”

      No. It is your brain modifying reality to fit its model of the world. It is a well known effect in psychology… can’t remember the name now.

      The sad situation of Germany is this:

      https://www.energy-charts.de/power.htm

      … most of the time when there’s “a lot” of sunshine (a lot for Germany, means not total obscurity)… like today… there’s no wind (high pressure area over central europe… no clouds from Sweden to Sicily but no wind either)… demand is normal for a mid-August day, factories closed, people outdoor…
      Demand is germany is diminishing, in the last 2 years, only because of unseasonably warm winters, and the usual, neverending improvement of efficiency.

      • gweberbv says:

        Roberto,

        one last try before I give up. Have a look at this plot: https://postimg.org/image/kpney6vz3/
        There I compare two weeks in July. The second week has rather stable conditions with respect to PV and wind production. And the consumption curves (production plus/minus imports/exports) for the five working days look nearly identical. But not so in the first week under investigation.

        Probably, you do not give a sh*t what I want to discuss here. But maybe someone else find this observation useful. (Though it could also just be an artefact from the methodology AGORA and energ charts are using to process their data.)

        • Greg Kaan says:

          There is this example of industrial demand management by Trimet (the article is fundamentally incorrect about the ability of the smelter to return power to the grid).

          Maybe there are more?

          http://www.bloomberg.com/news/articles/2014-11-26/germanys-trimet-aluminium-turns-smelting-tanks-into-batteries

          • Greg Kaan says:

            Proof that Bloomberg (and a lot of other, mainly renewables orientated, media reporters) totally misunderstood what Trimet was aiming to achieve.
            The “virtual battery” was all about demand management.

            http://www.energiapotior.com/the-virtual-battery/

          • gweberbv says:

            Greg,

            thanks for this information. Yes, that could be a reasonable explanation where this additional demand might be coming from. More than 3 GWh ‘battery capacity’ in a single plant is quite something.

            However, the 5 billion liter of warm water that are used in German households per day translate to roughly 250 GWh (if my math is correct). Most of this warm water is provided via burning gas. Adding resistive heaters for optional use in times of high electricity supply would be a relatively cheap way for much more flexible (electricity) demand.

          • depriv says:

            @gweberbv

            For household warm water to be utilized that way you need to add hotwater tanks, resistive heaters and control.
            For the control, you need to set minimal and maximal water temperatures. Only the temperature change between the limits can be utilized: and also, you have to sum up the available energy sink real time to provide control signals for the individual heaters.

            Can be done, but it’s not as easy and cheap as most would think it is.

            As for the price – dunno. There are local CHP plants, with water tanks already available. But as far as I know there were no experiments conducted for this.

          • gweberbv says:

            Depriv,

            as at the moment gas is used as the standard heat source in Germany, most buildings are already equipped with water tanks. In fact since about a decade, if you install a new heating system based on fossil fuels you are more or less forced to install a relatively big water tank because you need to install solar thermal collectors as well.
            The only thing that is (technically) missing is a heating rod inside the water tank and a control unit that knows when electricity is cheap. (Of course a heat pump would be more efficient but is also much more expensive.)

          • robertok06 says:

            @gweberbv

            “The only thing that is (technically) missing is a heating rod inside the water tank and a control unit that knows when electricity is cheap. ”

            The only thing which is missing in your analysis is that the heating rod in germany would heat that water tank for 4 full months, making it impossible to store all of this extra energy… to be re-used during the 4 low-insolation months…
            The “when electricity is cheap” hinting at intermittent german renewables wind and (most of all) PV is simply ilarious… you mean “cheap” like 4 times more than electricity from the grid? C’mon!

          • gweberbv says:

            Roberto,

            what you can achieve with the existing hot water storage tanks in the buildings in Germany is heat storage for a few days at most. (Only hot water for use in the households. Space heating is not considered.) This means flexible demand in the order of a few hundred GWh, while today daily demand is in the order of 1000 to 1500 GWh. I would call that an awesome fraction of flexible demand.

            Now go and put a cup of hot water into your fridge. Maybe you need that hot water in a few months.

            (Side remark: Low-insolation months are windy months. The sum of wind and PV production is relatively stable over the year if aggregated for a month: http://www.directupload.net/file/d/4450/fdvug2rg_jpg.htm
            Nobody needs to store nothing for more than a month.)

          • robertok06 says:

            @gweberbv

            “Nobody needs to store nothing for more than a month.)”

            Great!… for Germany along this would mean approximately 60 TWh of storage needs (not including losses)… easily doable, right Guenter? 🙂

            … you will just need to store lots of hot water anywhere possible.

          • robertok06 says:

            @guenter

            “The sum of wind and PV production is relatively stable over the year if aggregated for a month:”

            ???
            WHAT???
            Your “relatively stable” goes from more than 11 TWh/mo to less than 5!… Guenter, get real man!… can’t keep on saying one thing and linking data who show the opposite. A factor of more than 2 for a country like Germany is not workable.

          • gweberbv says:

            Roberto,

            look again at the graph. Then look at the calendar.

            Hint: August (8th month of the year) is not over yet. Monthly production of PV and wind power fluctuates between 8 and 11 TWh in this year so far.

          • robertok06 says:

            @guenter

            “fluctuates between 8 and 11 TWh in this year so far.”

            Doesn’t change much!… once you have to supply 600 TWh/y manly via a combination of wind and PV then even with this kind of fluctuation there is a need to store tens and tens of TWh… which is physically impossible, not to mention the costs, and the social acceptability, and all the rest…
            You remind me one of those japanese soldiers on a small island in the pacific, keeping the faith in the emperor 40 years after the end of WW-II.
            The war is over, guenter, and intermittent renewables have lost it. They are nothing more than a giant Ponzi scheme, a legal scam.

        • robertok06 says:

          OK, you convinced me… now show the same analysis/plot for any of the 4 months between November and February.
          And then…it is me who doesn’t give a sh*t right?

  13. Leo Smith says:

    All you need you know about smart grids:

    A 1% solution to a 70% problem. Cosmetic engineering. Anything to keep the renewable emperor’s clothes apparently decent. And yet another chance to force you to buy kit you never knew you didn’t want and certainly don’t need.

    • Greg Kaan says:

      Exactly. All it can do it smooth out the peaks and valleys.

      Smart grids should be the last measure implemented after the long term energy storage issue has been solved.

  14. Olav says:

    There is a way a tiny population on a rainy island or elsewhere could construct a “special PHS” system that is a single intermittent free system that does it all without enforcing strong demand control. Wind turbines, PV, inverters, battery chargers, batteries, diesels all controlled by a sophisticated control system and still is a strong demand control used… none of it is needed. It can be done without smart grid.

    With special PHS I mean a constructed dam at high elevation which is filled by pumping up water on 150 rainy and soaked soil days from a small intake at 1/2 of dam elevation or higher.
    The dam must have storage to tide over 2 months of “rain lull” The rain hitting the dam exedes evaporation and seepage This is the ideal battery 1 KWh in and 1.5 KWh out or more and lasting 50+ years.

    • Greg Kaan says:

      I think it’s a given that enough storage makes the intermittency problem go away. The issue then becomes the cost/logistics for the storage in both energy and power capacity.

      And you still need to factor in the overbuild for generation.

      • Olav says:

        Peak demand in afternoon is maybe 3x average demand needed for a few hours. Let the pump rest then and all goes for demand. You need to overbuild generation to cover peaks anyway.
        50 households a’ 10 000 KWh requires 500 000 KWh and 200 000 KWh storage. A 5m depth lake constructed on a flat plateau at 300m a circular wall with 140m radius can provide that. Each household share is 20m of 6m high earth dam, maybe it could fly economically. The rest (pipes, turbines, generators & pump) may cost the same as the dam. I do not believe a 94% subsidy is needed.
        A wind + battery solution requires a 2000 ton battery for the same storage. Each household share is then 40 tons of battery. At 200 $ a kilo it is a 8 million US dollar expenditure which have to be repeated every 10 years! Batteries are only for short burst charge/discharge services.
        The least costly is cable to mainland if distance is reasonable. Utsira in Norway is 17 km from mainland power connection. The population is 200 and some businesses. The new replacement cable is estimated to 3 million US dollars. The islanders are asked to pitch in half of that and they are asking for more subsidy.

        • robertok06 says:

          “Each household share is 20m of 6m high earth dam, maybe it could fly economically. ”

          No, it doesn’t. And it doesn’t fly ecologically either.

  15. Olav says:

    Sorry 200 Dollar a KWh makes 800 000 for each household which still is extremely costly. Even if required storage is cut in half and same with price it is 200 000 every 10 year

  16. Grant says:

    In respect of the King Island experiment ……

    When I was reading what I could find of the background information about a year ago two things hit me.

    Firstly the demand management is not island wide. I seem to recall that only about 100 installations are connected (so possibly about 20% of primary demand given the population) and taking part in the trial. That would seem to fit with the target scale on the display.

    Secondly the original plan (and the original battery development) were based on an island with a substantial food processing plant which has since closed. The plant represented something line 1/3 of daytime demand (from memory). That’s quite a large variation of plan to actual requirement.

    One of the great difficulties of extended networks, if they are to be cost effective long term, will be to estimate demands a long way on the future. Not so bad when demand is growing and the latest and greatest technology can be deployed as it becomes available. However a bit more critical in a declining market in order to avoid obsolescence before activation.

    Any extremely beneficial advances in technology that might somehow appear, as in the computer industry over the past 40 years or so, might prove difficult to implement in a spreading but primarily “old tech” based system. Maybe the cost effectiveness of longevity and the cost estimated related to it are rather spurious.

    As for an earlier comment about subsidies and how they have always been part of the mix for socialising the shared cost of energy convenience – true. In effect the subsidies, if committed wisely and equitably, are merely a return of taxation that has been used to develop mutually beneficial utility for all or nearly all populations.

    However if used unwisely they are simply a drain on resources and a distortion of social balance that might well result in less than desirable results.

    I have no faith in the ability of politicians and businesses to get a correct balance in a local/regional/wide area/country/continent/worldwide grid concept that all people would think of as “fair and reasonable” at all times.

    Quite how one might create and manage a low risk strategy for reliable supply in such a market at an affordable cost is difficult to see in the absence of either decades of experience from operation or the creation of a Global Government. (And then some ….)

    Finally, writing in The Telegraph, Ambrose Evans Pritchard seems to have been fed a very rose tinted view of the future developments in renewables market technology. Or is there about to be a completely genuine revolution in what is available that will totally change the way we need to think about what the future may possibly hold?

    http://www.telegraph.co.uk/business/2016/08/14/britains-vast-national-gamble-on-wind-power-may-yet-pay-off/

    This and other recent articles form the same source could be of interest as discussion generators.

  17. Leo Smith says:

    This and other recent articles form the same source could be of interest as discussion generators.

    In a blog devoted to the analysis of political marketing and corporate psychology, perhaps: Not in one devoted to engineering analysis of energy sources.

    Ambrose writes what he is paid to write, and the appearance of renewable puff pieces all over the sceptic blogosphere plus the appearance of green shills and astoturfers is statistically significant: WE have a government that is worrying the renewable industry. Money is being spent to instil doubt on the thesis that all renewables are utter crap and should suffer subsidectomies or euthanasia immediately.

    Smart grid/storage/molten salt/flywheels/BEV storage/yadda yadda/ All tried, all found wanting and in any case several times more expensive and or environmentally damaging than fracking and nuclear.

    Or: “technological advances will save us” betraying total lack of understanding of the difference between the ability to develop a technology towards a theoretical maximum and the ability to discover a technology based on entirely new principles of physics.

    The renewable industry must have competent engineers capable of counting beyond ten without taking their socks off: yet this complete fraud of dishing out cat belling solutions to fundamental issues of renewable energy continues to be perpetrated. Ergo they know what they are doing. Defrauding society of taxpayer cash based on schemes they know will never work. This is the height of criminal irresponsibility. In the USA it is known as racketeering.

    Not only is it criminal, it is socially beyond irresponsible. Merely making money would be bad enough, but to put the energy infrastructure upon which society depends at real risk is on a par with war crimes and potential genocide.

    The green/renewable industry are in fact everything they warned you about: racketeering conscienceless profit motivated rent seeking environmentally destructive socially irresponsible mafia. Who will if unchecked destroy the world for the next generation.

    In a couple of generations it will pass into history as the Nazis did as one energiewiende after another gets uncovered and shown to be what it really was.Massive corporate and political fraud.

    We are engineers. It takes very little – as many articles here show – to demonstrate in detail what we already know. Renewable energy is mere cant. Just because huge sums are poured into marketing of it, does not make it valid or workable, and the chanting of the Bandar Log – the new useful idiots of the watermelon society – does not make it into what it is not.

    (If you are not familiar with the Bandar Log, the belling of the cat, or the reference to water melons, google is your friend)

  18. Nial says:

    I wonder what engineers who have to design and maintain the grid think about “smart”.

    My understanding is that the grid is a fixed solid thing that provides power at tightly controlled frequencies and reasonably tightly controlled voltages. Having massive spinning generators helps maintain things within limits.

    Also having centralised generation with a tree like distribution network also makes system protection easier, with breakers that isolate faults as ‘far out from the center’ as possible, leaving most of the rest of the system unaffected.

    1) The grid is not supposed to be ‘flexible’.
    2) Changing the topology so generation is much more distributed with power flowing in both directions throughout the system is going to make protection mechanisms a nightmare to implement.

    God help them (/us).

    • gweberbv says:

      Nial,

      I disagree with the assumption that distributed generators are – in principal – a bad thing. The grid operators could use many thousands (if you considers also very small residential installations: millions) of inverters to control and correct voltage and frequency.
      This can be an asset, not only a problem.

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