Is large-scale energy storage dead?

Many countries have committed to filling large percentages of their future electricity demand with intermittent renewable energy, and to do so they will need long-term energy storage in the terawatt-hours range. But the modules they are now installing store only megawatt-hours of energy. Why are they doing this? This post concludes that they are either conveniently ignoring the long-term energy storage problem or are unaware of its magnitude and the near-impossibility of solving it.

The graphic below compares some recent Energy Matters estimates of the storage capacity needed to convert intermittent wind and solar generation into usable dispatchable generation over different lengths of time in different places. The details of the scenarios aren’t important; the key point is the enormous differences between the red bars, which show estimated future storage requirements, and the blue bars, which show existing global storage capacity (data from Wikipedia). It’s probably not an exaggeration to say that the amount of energy storage capacity needed to support a 100% renewable world exceeds installed energy storage capacity by a factor of many thousands. Another way of looking at it is that installed world battery + CAES + flywheel + thermal + other storage capacity amounts to only about 12 GWh, enough to fill global electricity demand for all of fifteen seconds. Total global storage capacity with pumped hydro added works out to about 500 only GWh, enough to fill global electricity demand for all of ten minutes.

Yet microscopic additions to installed capacity are apparently considered a cause for rejoicing. Greentechmedia recently waxed lyrical about the progress made by energy storage projects in 2015 . “Last year will likely be remembered as the year that energy storage got serious …. projects of all sizes were installed in record numbers ….” But when it goes on to list “the Biggest Energy Storage Projects Built Around the World in the Last Year” we find they’re all 98-pound weaklings:

Also notice that while megawatts are specified MWh usually aren’t. There are two possible explanations for this. First the facilities aren’t designed to store energy. They are primarily for frequency control, load following etc. The MW are important but the h aren’t, or at least not very. Second, the policymakers who mandate these facilities don’t see any difference between a MW and a MWh.

And I say “mandate” because that is what the state of California recently did. California recognized that it would have to solve some grid stability problems before it could expect to meet its 50% renewable energy by 2030 target, so in 2013 it passed a “Huge Grid Energy Storage Mandate” that required the state’s big three investor-owned utilities to add 1.3 gigawatts of energy storage to their grids by 2020. Three points are worthy of note here:

  • Relative to California’s 50GW peak load 1.3GW can hardly be described as “huge”.
  • The mandate again doesn’t say how long the storage should last, i.e. how many gigawatt-hours are needed.
  • The proposal specifically excludes pumped hydro storage projects of 50 megawatts or more.

And the rationale for excluding pumped storage projects over 50 MW deserves a paragraph all to itself:

The California Public Utility Commission concluded that although large-scale pumped storage hydro meets the statute’s definition of an energy storage system, it must limit the size of eligible pumped storage systems in order to encourage the development and deployment of a broad range of energy storage technologies. In the CPUC’s view, the goal of creating a new market for a range of storage technologies would be undermined if the IOUs could meet their targets by acquiring a pumped storage facility: The majority of pumped storage projects are 500 MW and over, which means a single project could be used to reach each target within a utility territory.

What is this broad range of storage technologies that pumped hydro threatens to undermine? Based on proposals received to date they include bi-directional EV charging stations, molten sulfur batteries, zinc hybrid cathode batteries, lithium-ion batteries, thermal energy stored in ice, in used EV batteries and in rechargeable electrolytes. In short, California will consider any type of energy storage system provided it isn’t pumped hydro, the only large-scale energy storage technology that can be guaranteed to work.

Which brings up the question of which of the technologies don’t work. In the recent ARES post Greg Kaan made the following comment:

This thread is turning into complete nonsense, not due to the commentators here (thanks Greg) but simply through the “solutions” being presented to try and cope with intermittent power production.

And Greg is quite correct. The solutions being presented to cope with intermittent power production range from green dreaming to downright bonkers. Here’s a selection, courtesy of Wikipedia:

Compressed air
Liquid air
Electric vehicles
Underground hydrogen storage
Power to gas
Hydro and pumped hydro
Superconducting magnets
Thermal storage.

To which I will add:

ARES rail storage, which we recently looked at.

The 500m-diameter underground granite cylinder that moves up and down without ever cracking, leaking or getting stuck

Flat Land Energy Storage, which was reviewed here.

Anyone who can see a way of commercializing any of the unproven technologies on the list is encouraged to provide details. (Although two of them are in fact capable of providing meaningful amounts of storage. The first is power-to-gas, which was dismissed here as being far too complicated, inefficient and uneconomic. The second is very-large-scale pumped hydro, which was discussed here. The project delivered 6.8TW of storage but involved turning a large chunk of the Scottish Highlands into an inland sea.

So here we have an impossible situation, with green pipe-dreamers and utilities whom one suspects should know better trying to solve an unsolvable problem with technologies that have no chance of solving it. So what happens next? Well, at some point something obviously has to give, but what, where and when is the question.

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124 Responses to Is large-scale energy storage dead?

  1. Peter Lang says:


    Thanks you for this. I view the energy storage issue as just about the most important constraint preventing weather-dependent renewables becoming economically viable.

    When energy storage is included, ERoEI is a fundamental constraint: “Catch 22 of energy storage

    I responded to comments by Dave Rutledge and Olav on the previous thread. It shows the magnitude of the energy storage issue for renewable energy. so I’ll post again below:

    Dave Rutledge said:

    I would do a power rather than an energy calculation here.

    I disagree. If the problem we want to address is to make weather dependent renewables dispatchable and baseload capable, then the issue is primarily energy storage capacity, not generating capacity.

    Olav said:

    Smoothing out seasonal solar variations is almost impossible

    Olav is absolutely correct. This illustrates the magnitude of the problem:
    Solar Power Realities Supply-Demand Characteristics, Storage and Capital Costs
    Web post and comments here:

    This is a simple, limit analysis of the solar PV capacity and energy storage capacity that would be required to supply the Australian National Electricity Market with power to meet the 2010 demand profile. It is a limit analysis in that the profile of power supplied is scaled up from a single commercial PV power station in Queanbeyan, NSW (at latitude 35 S, 200 km inland). The power readings are at ½ intervals and continuous for 2 years.

    Figure 7 (in the PDF linked above) shows the capacity factor for continuous periods of 1, 3, 5, 10, 20, 30, 60 and 90 days. The lowest capacity factors were in winter and were:

    5 days = 4.3%
    10 days = 5.7%
    20 days = 6.6%
    30 days = 7.8%
    60 days = 8.6%
    90 days = 9.4%

    Average energy consumption in winter is 600 GWh per day (average 25 GW). At the capacity factors listed above the solar generating capacity (GW) required to provide 25 GW average power per day for different amounts of energy storage would be:

    5 days = 686
    10 days = 524
    20 days = 448
    30 days = 383
    60 days = 347
    90 days = 315

    The least cost option is with 30 days pumped hydro storage (if sites were available, which they are not), i.e. $2,800 billion – versus $100 billion for nuclear to supply the same average power (Figure 10).

    The land area required would be 11,000 km2 (8,000 km2 for pumped hydro reservoirs and 3,000 km2 for solar PV) versus 26 km2 for nuclear plants. The CO2 emissions would be 20 times higher than with nuclear.

    • Roger Andrews says:

      Peter: Thanks for your detailed response. Just a couple of points.

      We’re talking about basically two intermittent energy sources – wind and solar. Wind is stochastic, and while you can reduce its overall variance by combining output from an increasing number of turbines – which helps with short-term balancing – you will never be able totally to get rid of those pesky nights/days/weeks/months when you need the power but the wind stubbornly refuses to blow.

      Solar balancing, however, is trivially simple. All you need to do is connect solar parks of equal size in antipodal locations and you get a nice flat output. My April 1 post was going to be titled “The Melbourne-Madrid Multi-Terawatt Interconnector”, but Euan beat me to it.

      • Peter Lang says:


        I do fully realise your point about wind + solar. That’s why I said that it is a “limit analysis” and explained. There is more if you read the link. It’s also why I’ve pointed out in a later comment that GB would need 8 TWh for three weeks of worst wind and solar output in 2012 scaled up to provide 100% of GB’s demand for that period with wind and solar each contributing 50%. I’ve referred to the ERP report for GB many times in replies to you and Euan’s on many previous threads and suggested you look at it, but never received a response. It is here:

        Regarding the global electricity grid, I’ve previously estimated the cost for that, but that’s not on topic for this thread and a distraction for this post.

        • I’ve referred to the ERP report for GB many times in replies to you and Euan’s on many previous threads and suggested you look at it, but never received a response.

          Peter, you are a valued commenter on Energy Matters, so let me explain why.

          Yesterday April 8 (UK time) 82 comments were posted on Energy Matters, many of which contained long tables of numbers and/or links to studies that in some cases would have required hours to synthesize and respond to. Euan and I are encouraged that our posts are attracting so many comments from people who for the most part clearly know what they are talking about and who have much to contribute, but with all the other things we have to do to keep the blog running we just don’t have the time to respond to more than a few of them. And being unable to check the content of all the links our selections aren’t always optimum.

          I did in fact read through the ERP report. I found it a curious read, a mixture of green pipe-dreams and hard-nosed engineering. But the reason I didn’t comment on ERP’s 6-8TWh storage estimates for 2 and 3 week low-wind periods was that these were of the same order of magnitude as the numbers I’d been coming up with in and elsewhere. In short, they didn’t change anything. Had they been only a tenth or a hundredth as large a response would have been forthcoming.

          We’ll continue to do our best to respond to as many comments as we can in the future, but unfortunately can’t guarantee full service to everyone

          • Peter Lang says:


            Energy Matters is excellent. I appreciate Euan’s and your posts and recognise neither you nor anyone else has time to read all the comments and all the links. However, sometimes comments have been somewhat dismissive or condescending without having read the link that supports the short statements that can be made in comments.

            I did in fact read through the ERP report. I found it a curious read, a mixture of green pipe-dreams and hard-nosed engineering.

            It would be interesting to discuss what you see as the “green pipe dreams”. I’d like to understand what assumptions and inputs cause significant errors in the results.

            I have my own issues with some of what appears to be an agenda; this was revealed in comments here: Is nuclear the cheapest way to decarbonise electricity , for example: arguing that a carbon price is inevitable and necessary, advocating for a carbon price of £100/t CO2, seemingly advocating for anything but nuclear and “all of the above”, advocating for CCS and, significantly, not willing to acknowledge that the results presented in the ERP report show that nuclear is the least cost way to decarbonise GB electricity. But apart from those points of disagreement which came out in comments, I am not aware of any significant errors in the ERP analyses. It seems to me to be an excellent analysis and an example of what all policy analysts should be doing. I would be very interested to hear if there are any significant problems with the analysis. I understand that it is being taken seriously by DECC and influencing the policy analysts. So, a serious critique of it on Energy Matter could be valuable.

            If you do decide to critique it, I hope you might have time to read my main post on it (see link above). The main takeaway message is:

            “The results presented in the ERP report show all or mostly new nuclear capacity is likely to be the cheapest way to decarbonise the GB electricity system to meet the recommended 50 g CO2/kWh target. The ERP analysis used the central estimates from the DECC commissioned Parsons and Brinkerhoff reports (17 July, 2013) here:”

    • Dave Rutledge says:


      “I disagree. If the problem we want to address is to make weather dependent renewables dispatchable and baseload capable, then the issue is primarily energy storage capacity, not generating capacity.”

      I had already done the pricing for energy, $/kWh, for ARES in the first comment of Roger’s post. In ARES the price for energy, basically the mass of sand or gravel, is distinct from the price for capacity, which is cost for railcars and locomotives.


      • Peter Lang says:


        I didn’t realise you were serious that the price for storage is the price of sand. I posted a response but it was deleted. Your comment started “I am rooting for ARES. “. But didn’t give an estimate for the $/kWh storage capacity. The cost of storage capacity is the capital cost divided by the amount of storage capacity.

        • Dave Rutledge says:

          Hi Peter,

          In ARES the energy storage is a mass like gravel or sand in a container in a gravitational potential. The masses slide on and off railcars, so the railcars are not properly part of the storage, but rather the capacity.. A metric ton mass raised the amount Roger suggested, 640m, would store 1.7kWh. You can apply whatever cost you think is reasonable per ton and divide by 1.7kWh to get the cost per kWh. I assumed $5/ton to get $3/kWh. Whatever you assume is an order of magnitude or more better than any conceivable battery.


          • Peter Lang says:


            Thank you for your replies. Much appreciated. (sorry, we are posting comments at the same time on two threads.)

            I am still not clear what cost you are calculating for the energy storage capacity ($/kWh) for ARES?

            My understanding is the main concern is storage capacity, not generating capacity, so the primary issue for comparison with other options is the cost of energy storage capacity.

            However, I suggest, for the cost comparison to be useful we need to compare the cost of two systems that meet demand and other requirements of the electricity system. For example to be dispatchable and baseload capable we need to include the capital cost of the generators, transmission from generators to storage, and storage.

            Using Roger’s ARES numbers, I very roughly estimated the cost of storage capacity for a system comprising solar PV generating capacity plus transmission to storage plus 250 GWh of ARES energy storage to be $1,144 billion = 4.5/Wh = $4,500/kWh.

            This seems wrong (an order of magnitude too high). What am I doing wrong?

          • Peter Lang says:

            I think my estimate of the capital cost of energy storage with ARES using Roger’s figures is correct

            First, let me some possible confusion over what the estimates by various commenters are referring to.

            1. Capital cost of generating capacity – $/W or commonly $/kW
            2. Capital cost of energy storage capacity – $/Wh, $/kWh, etc.
            3. Cost of electricity – $/Wh orcommonly $/kWh, $/MWh

            I was estimating #2, cost of energy storage capacity. Willem Post estimated the cost of electricity.

            I’ll simplify the basis of estimate for the capital cost of energy storage. From Roger Andrews’ figures on the ARES thread:

            ARES system capital cost = $55 million
            Energy storage capacity = 12.5 MWh
            Yherefore, Capital cost of energy storage = $4.4/MWh = $4,400/kWh = $4.4 billion/ GWh

  2. Euan Mearns says:

    All energy storage concepts work, the issues are always one of cost and scalability. On scalability, I think only chemical storage can work – H2 and CH4, and of those CH4 is probably most practical although a source (and cost) of CO2 may prove unresolvable. That leaves H2.

    The real upfront problem here is cost. The inputs are very expensive subsidised RE and 70 to 50% gets wasted in the round trip conversions. And so what is needed to get around this is VERY, VERY cheap RE.

    • Alex says:

      As you say, with chemical storage, the issue is not so much KWh as efficiency. Electrolysis + Fuel cell comes to between 30% and 60% efficiency.

      The only sensible way to make hydrogen on a vast scale is using thermal process – heat > hydrogen. There may be ways of achieving this using solar power, but ultimately, I’d see high temperature nuclear reactors that can swtich between producing electricity and producing hydrogen using the sulfur-iodine cycle.

      Molten Salt reactors, as currently planned are not hot enough (they are aiming for steam at 600C), but with some materials tweaking, could go up to 800C. In this case, both electricity and hydrogen production could be 60% efficient (from heat!)

      Whether the hydrogen is used as hydrogen, or turned into methane, ammonia, or another carrier, is another question.

      • Greg Kaan says:

        I made this comment in another thread here but I think it is worth repreating.

        On the Brave New Climate site, one of the commentators (who occasionally posts comments here), singletonengineer, has had considerable experience in the power generation industry and has nothing good to say about his experiences with handling hydrogen (used to minimise windage in generators). Fires and explosions appear the order of the day due to the high permeability of hydrogen vs other gases. In fact, his experience is that most power plants get their hydrogen from oil refineries in gas bottles rather than going through the issues of electrolysis and storage. Hopefully, he will post here to clarify (correct?) my statements.

        BTW I am somewhat flabbergasted that one of my comments has been quoted by Roger Andrews in an article

        • Did I do something wrong?

          • Greg Kaan says:

            Not at all. I’m just extremely flattered you felt it was worth quoting, Roger, since I’m a total layman in this area. I think this site is the finest of its kind and if I am contributing in any way, then I feel a sense of accomplishment.

          • Roger Andrews says:

            If you’re a total layman I shudder to think what that makes me.

        • singletonengineer says:

          Hi, Greg.

          Hydrogen is always dangerous but of course these risks can be managed.

          The trick is never to give it a chance to do what it does naturally. Never cut corners. Keep your guard up at all times. Don’t depart from established systems without thorough consideration and planning – eg don’t change a flexible hose without proper certification. It happened. A large fire ensued.

          Other issues have arisen due to oxygen entry into the LP side of things via failed seals or even failure to properly maintain valves, mechanical plant or seals, overlooking routine testing and recertification of HP storage cylinders, inexpert operators, overpressurisation of components – the list is substantial.

          These risks can be magnified because power station staff are multidisciplinary beasts and hydrogen handling is not their core business.

          OTOH, purchased-in packaged hydrogen removes most of the generating, compressing and handling risks. Suppliers might even provide dangerous goods storage and handling service as part of their duty of care for their own staff – hence, mandatory expert independent review of the receipt and storage aspects of things.

          Besides which, even with very low marginal costs of electricity at coal fired baseload plant, the cost of production can be higher than the cost of hydrogen produced in a dedicated facility from natural gas and trucked to site.

          I don’t favour H2 storage if there are other large scale energy storage options available.

          • Alex says:

            So, if we produced hydrogen from nuclear heat, should we:
            a. Attempt to ship and use compressed or liquified hydrogen for our cars and other mobile needs.
            b. React it with nitrogen to use ammonia as the energy carrier.
            c. Work on getting CO2 out of air or water, and reacting that with the hydrogen to form methane or some other easy to handle, familiar hydrocarbon.
            d. Skip the hydrogen altogether. There are some proposals to use Boron as the fuel of choice. Cars would fuel up on boron tubes, and return boron oxide powder to the garage for electrolytic reprocessing.

    • willem post says:


      “Total global storage capacity with pumped hydro added works out to about 500 only GWh, enough to fill global electricity demand for all of ten minutes.”

      Active capacity, MW, of pumped hydro reservoirs, batteries, etc., is at least 20% less than total capacity.

      Useful energy, MWh, supplied to the grid from any storage is least 20% less than energy supplied to storage.

      When wind and solar energy quantities are large, energy capacity and storage are correspondingly large; the latter must be large enough to deal with multi-day
      no-wind/no-sun conditions, as occur in Germany, etc., during winter.

      If no fossil fuels, biofuel-fired CCGTs could be supplementary to energy storage systems for peaking, filling-in, and balancing.

      Without about 50% nuclear, there is no feasible way to provide affordable energy to the world.

  3. Peter Lang says:

    Another estimate: “to convert a 3 week period of 2012 UK wind and solar (at 50% of each and sufficient capacity to provide 100% of UK’s demand) into dispatchable energy is 7.9 TWh ( Figure 10: )

    Also, note a typo near the end “500 m diameter” should read 500 m radius or 1 km diameter in this:

    The 500m-[radius] underground granite cylinder that moves up and down without ever cracking, leaking or getting stuck

  4. The ‘rationale’ for excluding pumped hydro is surreal. They’re basically admitting this has nothing to do with energy security, or climate change or the environment. It’s about rigging the market and favoring some companies / technologies over others.

    • Alex says:

      That by itself is not bad. They may want to encourage the development of new technologies in California, which can then be exported. Pumped Hydro is not a new technology.

      It worked for a while in Germany, until the Chinese copied the solar technologies, only more cheaply.

      The UK is offering £250 million for new clean energy technologies. But it must be small modular nuclear.

      • willem post says:


        The Chinese copied old, off patent technology, and innovated by means of mass production, which made the ENERGIEWENDE solar part much less costly, and less of a folly, than it would have been, i.e., it gave the Germans a less expensive rope to hang themselves.

        What were they thinking? Solar in Germany?

    • Roger Andrews says:

      The California PUC’s decision to nix pumped hydro deserves a post of its own – but preferably one written by a psychiatrist.

  5. Euan Mearns says:

    I have also noted and been frustrated by the fact that many storage projects report power output but not MWh stored. I have concluded this comes down to either the intellect or integrity of those involved.

    • robertok06 says:

      Well, Euan, it rhymes with the slogans like “this wind farm will generate the electricity to power xx households”, which is total nonsense, as wind generates mainly at night, while most households typically sleep, and therefore need only a marginal amount of electricity.

      • It doesn't add up... says:

        I took a look at the data from Gridwatch on wind production in the UK, which covers about 17 months of hourly data. It shows on average a small dip in wind production in the late evening and small hours overnight. Standard deviation of hourly output is about 5% of average output.

        Warning: the data have some glitches.

  6. blr says:

    There is no need to make large-scale storage nowadays: for example in germany electricity prices in the afternoon or at night don’t really differ from the prices in the evening.

  7. mark4asp says:

    Renewable energy boosters and protagonists seem to be mostly incompetent fools. A lot of them are politicians, lawyers and bureaucrats with a tiny understanding of science and technology. They think to run the world with diktat like King Canute. The rest of them are mindless environmentalists who have always boosted renewable energy because, in their imagination, these are alternatives to nuclear power. Greens are often hostile to (and ignorant of) science and technology. Even fossil-boosters here admit, when fossil runs out, we’ll eventually have to move to some kind of nuclear power: fission, fusion, or both. Nuclear power is the inevitable power source environmentalists close their minds to.

  8. mark4asp says:

    Our new problem: too much electricity in the summer, too little in winter – brought to you with malice by solar power. Who’d guessed that a seasonally dependent power source would behave like that? Store that summer electricity? What with. Which reminds me: the DECC 2050 model maker. This complicated, but inadequate, program appears to take no account of seasons. Why am I not surprised?

  9. nukie says:

    The battery storages included in Grids are so far for Grid services and to maximize Grid utilisation by smoothing out power transported in the region. They are not designed for longer term storage.
    But I guess you first need to understand and calculate yourself the topic Grid size versus neccesary storage capacity.
    It si obvious that a planetary grid with distributed PV would produce a constant power output without any storage . And it is also obvious that PV in Scotland with extreme seasonal output would require a extremely big storage if you want it to provide constant power output during all of the year (which you call “dispatchable, although nothing is dispatched here in any way, it’s constant, to use the right wording)
    So somewhere between 250kWh/kWp and 0kWh/kWp depending on the grid size is the required storage.
    So depending on the relative prices of Storage and Grid, the economic optimum weather to extend grid or to use more storage varys. With prices so far, extending the grid is cheaper than building storage.
    So far Solar in Germany is just enough to remove the daypeak in demand, thus making the need for storage in the grid smaller, not bigger than with the conventional power before.

  10. Stuart Brown says:

    I started to write a rambling answer to Peter Lang in the ARES thread comparing the Sizewell B PWR (42 hectares, 1.2GW, 84% capacity factor) to the Greater Gunnard wind array next door (14,700 hectares albeit in the sea, 504Mw, 45.8% CF) but decided it was too long and off-topic. When I started to think about storage it occured to me we have quite a number of 500-1000m deep holes complete, at one time, with winding gear and multiple kilometre long rail track at the bottom and top. We just closed the last one at Kellingley, which was extracting 900 tonnes of coal an hour from 800m down. Could this be an ARES type solution? Power input/output – drumroll – 2MW. Presumably the masses could be moved faster and more of them, but getting Roger’s 300,000 trains down the hole dissuaded me from thinking further.

  11. Alex says:

    So California has to provide 1.3GW of energy storage! That is just so easy. A large bank of capacitors or a flywheel will achieve this for a few million dollar. I think the JET near Oxford (actually a paltry 300MW flywheel IIRC), and certainly the Laser Ignition Facility in the USA (GW of capacitors) have already achieved this.

    Without adding the “h”, it is meaningless.

  12. Alex says:

    A good article summing up the issues of scale.

    One other point is efficiency. So in theory CAES could be scaled up, but on a large scale has pretty poor efficiency.

    A company called EOS is developing Zinc Hybrid battery technologies and promises costs of $200/KWh. hmmm…. only $1.6 trillion to make German solar despatchable.

    You (Euan) did an analysis last year showing a UK wind/solar situation would need 3200 GWh. Only $640 billion. But that was for one bad winter. A northern country would have to cope with the worst (for renewables) winter in 1,000 years or more.

    Add to that, the Zinc Hybrid battery is only 75% efficient. So you also need to multiply the cost of renewables by 4/3, as well as adding the battery cost.

    Two technologies that could be more scalable are organic flow batteries – perhaps at a cost of $100/KWh – and pumped heat storage, as being developed by isentropic.

    Maybe this is in the crazy idea category – but the isentropic system could be deployed by using boreholes to heat up millions of cubic metres of sub surface rock. Frankly, that is the only way I can see of economically storing TWhs of electricity.

    • singletonengineer says:

      “…heat up millions of cubic metres of sub surface rock.”

      That will need to be bone dry rockwith no potential for inflows, otherwise all that heat will simply boil water.

      Good luck with finding a suitable site or sites.

      • It doesn't add up... says:

        It would make for a geothermal operation though, provided heat injection was below a cap rock – but I’d be concerned about the geological impact below ground with all that superheated steam and rock.

      • Alex says:

        If the rock is impermeabkle, then the water would be boiled out on first use, and no more would flow in. The hot region would fracture and become permeable, so would need a rain cover.

        Alternatively, it might be possible to find an abandoned quarry, line it with a waterproof surround, and fill it with gravel.

        We could even put the site in a mountain tunnel. Almost no surface impact, and certainly a lot less than for pumped storage.

        Though Isentropic still need to prove their technology with 1,000m3 tanks, before we move to 8E6 m3 volumes of mountain.

  13. Daniel says:

    Thank you for this post, Roger.

    EOS promises 160 $/kWh (or 145 €/kWh I guess) for their Aurora system (1 MW/4 MWh), but they have said so for more than two years without any single installation. If they succeed in deploying the technology, which I doubt, it will be quite a breaktrough in energy storage, supposing they have further room for price decreases.

    Today, you can have MW scale lithium ion for about 300-350 €/kWh (plus inverters and installation costs) and cheaper in the future, with efficiencies over 95% and more than 4000 cycles. Anyway, this still only makes sense in high value added services like frequency regulation and behind the meter industrial storage.

    Vanadium flow batteries are in the 200-250 €/kWh range for the storage part (liquid tanks), but power cells are quite expensive and efficiency is quite low (70-80%). If some type of flow batteries get cheaper (<100 €/kWh), either with organic or cheap metallic electrolytes, which is possible, this could become scalable and so a viable alternative for large scale energy storage.

  14. Thinkstoomuch says:

    A very good article, again, Thank you very much, Roger.

    Just asking this question here because I am not the sharpest spoon in the drawer. I just think too much and way too ineffectively.

    The Greentechmedia hits me over the head like a hammer. Again! Maybe someone here can explain it in little words.

    What the is the deal with the Solana power generating station? Basically advertised value for Solana, alone is within ~20% of everything totaled, 1,500 MWh. It went online 2 years ago .

    Solana is touted as storing 250 MW for 6 hours. It is providing 8 hours of power a day over a year. But everybody is acting Like Crescent Dunes is the greatest thing since sliced bread. Yet it is less than half the capacity with 2/3rds the energy storage, with 54% of the array size for half the price.

    Crescent Dunes: A billion dollars for 110 MW. Contracted to sell electricity for 0.0135 kWH. Array (based on Wiki) 1,197,360 m^2.

    Solana: 2 billion dollars for 250 MW. Selling electricity according to articles I have been able to find at 0.14 kWH. Array according to NREL is 2,200,00 m^2.

    Solana are actually delivering about 80+% of what they promised. Which for most renewable energy projects is fairly astounding. It really should do better they are basically losing an hour of what a 2 axis tracker should be able to do in that area. Might have something to do with it takes 30 MW to run.

    Yet Solana gets no mention by anyone not even the bird fryers and save the turtle types.

    Is Gila Bend, Arizona the leper colony or something.

    It really does seem both Solana and Crescent Dunes have undersized arrays. But see first paragraph.

    A confounded,

    • Thinkstoomuch says:

      Gah. Just noticed my contracted for price electricity had an extra zero. 0.135 kWh.

      My apologies,

      • singletonengineer says:

        13.5 cents US per kWh isn’t competitive.

        I have yet to find a thorough, costed, report for a successful solar thermal system, either power tower or linear fresnel, anywhere on the planet.

        By “costed” I mean including subsidies, grants, tariff support, in-kind assistance, free access to public lands (eg US federal deserts) and so forth, as well as the normal design, capital and operating costs.

        I’d be happy not to expect provisions for end of life activities, but the remainder of the costs are known or knowable. Why haven’t they been published somewhere, perhaps as a PhD thesis or a post-doc peer reviewed meta study?

  15. Nigel Wakefield says:

    Excess (solar/wind) power > methanol (CH4O) > (winter) CHP

    A better storage solution is liquids, not gas, due to enormously greater energy density (1litre methanol = ~4.42 kwh, relative to same spacial volume of methane 0.11kwh).

    I’ve very recently communicated with a business (Antecy in the Netherlands) that claims “we calculate the overall conversion efficiency, i.e. electricity to methanol to be approx. 50% for large scale applications” using their technology.

    Whether this can be substantiated or not, I don’t know. Nor do I know when the technology might be commercially available, nor at what cost…. other than that, it’s all good! Maybe someone here, more scientifically minded than me, might be inclined to talk with them to see how their claims stack up.

    Even going power to gas, per Euan’s suggestion, we need to drive towards CHP at a distributed level. There are a small number of residential CHP systems available at present,with heat/power ratios in the region of 6:1.

    If every British home replaced its gas boiler with a CHP system, we’d add >15 GW of power generation capacity almost all of which would be guaranteed to be operating at times of peak winter demand, and, pleasingly, operating at efficiencies in excess of 90% as there’s no waste heat. Not to mention what we could do with schools, SME workplaces, other public buildings, etc. Rolling out small and micro CHP at that scale would drive costs through the floor and technological development through the roof… and the power utilities out of business (which is why it won’t ever happen)

    I favour methanol in the long run; far more easily and cheaply stored than methane, and can be used for heat, power and automotive fuel (with a small amount of tinkering on a standard petrol internal combustion engine).

    • Euan Mearns says:

      Nigel, I agree a liquid is far better than a gas. But where does the CO2 come from to make the ethanol? To be emissions friendly it has to come from CCS – it ain’t ever going to happen. And I suspect the 50% efficiency you quote will be one way, i.e. making ethanol. Round trip will knock that back to 30% unless you can squeeze 80% out of CHP. The energy used in CCS will probably exceed anything you get out of storage.

      • Nigel Wakefield says:


        Methanol, not ethanol.

        According to Antecy’s website they have developed technology which captures CO2 from the air….( I’ve been around too long to take such claims at face value, but if true (and economically viable) it would be a game-changer. Notwithstanding, I don’t have the scientific nous to be able to substantiate the claim even wth access to the technology….

        As for CHP, at a distributed level (i.e. at point of use for the heat), the efficiencies are >90%. Existing systems for nat gas using Stirling engines or conventional internal combustion engines are (expensively) available at the moment. See Baxi Ecogen or SenerTecDachs ( Flow Energy also has one coming out ( [Flow also have really good deals on electricity supply… I’ve just changed to them from EDF Energy, saving myself >25% on annual power bills in the process!!]

        I hesitate to mention that micro CHP is also eligible for Feed In Tariffs at present, though with mass deployment those will disappear in the blink of any eye as prices drop.

        CHP also works with Fuel Cell technology though I’m struggling to come up with a name of an existing system at the moment.

        All of these will work equally well with methane….. with some small tinkering by the manufacturer.

        What I like about methanol is it can be centrally manufactured and stored and then distributed easily and cheaply to point of use (using methanol powered vehicles), as well as its versatility as a fuel. Beats hydrogen hands down and is more compatible with existing technology.

        I can imagine the Sahara and the Atlantic coast of north Africa (Morocco, Mauritania) as vast methanol factories using abundantly available solar and wind. Liquid power, transported by (and powering) ships, rather than thousands of miles of expensive and vulnerable interconnections… and those are by no means the only places in the world good for it. Saudi could do the same, and leverage existing under-utilised oil/NGL pipelines. Central Australia…. the south west USA… etc, etc, etc.

        On another note why bother with the multi-billion cost of the LNG liquefaction/trasnportation/rgasification chain, when you create the value chain so much more cheaply by converting the methane to methanol at source????

        The mind boggles….

        • It doesn't add up... says:

          I’d take the CHP efficiency with a pinch of salt. The problem is that it is only that efficient when there is demand for low grade heat to match capacity, and the economics really depend on continuous 24×365 heat demand. CHP works well with a paper mill, but not so well in a domestic setting.

    • Alex says:

      50% electricity to methanol is a significant waste of energy – destroying high value electricity to get low value chemical fuel.

      For this to work, we need to convert heat to chemical energy, which probably means high temperature nuclear reactors making hydrogen. Then making methanol from atmospheric CO2 will be very, very useful.

      Fuel cells are great as long as we’re using natural gas. They’re not promoted enough because they use gas – the good being the enemy of the perfect, whatever that is. But 20 million fuel cells, each able to provide 2KWe, would solve the Britain’s capacity problem. In the summer, they would only be used in emergency, but in winter, they could provide much of the countries electricity. The trouble is, fuel cells are still very expensive.

  16. I would recommend to pay a look to the presentation on batteries made by Fabien Perdu at

    • robertok06 says:

      Dear dr Prieto,

      I want to thank you a lot for having given the link to this workshop’s web page, and all of the nice presentations in it!… a wealth of data by knowledgeable experts… really interesting stuff.


    • Beamspot says:

      Don Pedro, I was across this page few days ago, from the link you posted at Crisis Energética, and I have to disagree with some data presented regarding Lithium batteries.

      My experience (and experiments) with real lithium batteries as well as my second and third hand links that work with them in the automotive sector where I also work, state that there is NO Li chemistry that withstands more tan 2000 100%DOD on the real capacity, even less the 5000 claimed in that document.

      Recent published information confirmed my early guessings from years ago that Tesla Model S batteries last less tan 1000 100% DOD cycles, in the stated range of 600 to 750, best real worls condition, less in hot places like our iSpain, thanks to Arrhenius.

      Those are high energy batteries, the cheapest and lightest ones (my calculations from last 2015 september give me a rough 100 – 110$/KWh just in raw materials), although the shortest live ones. High power Li-Pol batteries (like Leaf’s pack) range in the 1500 cycles at best, with an estimation of 130 – 140$/KWh), and LiFePO range on the 2000, and >150$/KWh.

      High power batteries have lower material efficiencies and higher CO2 and pollutants emition per KWh than High Energy batteries.

      Anyway, ESOI is my concept of choice, much better than KWh (mandatory since this is the storage measurement, it is usless/senseless to speak about energy storage and don’t give any figure in KWh).

      Cycles are important, but it is not the same to compare day cycling (365 cycles per year) than seasonal storage, at 1 cycle per year. 1000 cycles is a looooooooooong time to check plausability…

      I wished to post a long entry, but I guess this huge amount of comments request from my side to be short.

      Only one last comment: there is some kind of easy and cheap seasonal energy storage system: biomass.

      My worst fear is that will lead us to the Galactic Eastern Planet.

    • Peter Lang says:


      Thank you for the link to ‘ Science for Energy Scenarios: 3rd Science and Energy Seminar at Ecole de Physique des Houches, March 6th-11th, 2016 And thank Robertok06 for highlighting it. It includes many presentations on ERoEI. My comments on two of them are:

      1. Jessica Lambert ‘Examining The Relation between Quality of Life and Biophysical vs Economic Conditions charts Human Development Index versus EROEI (for society). If this analysis is correct, it shows how significant achieving a high EROEI (society) is for improving human well-being.

      However, it seems to me many of the presentations are using energy intensity as a proxy for ERoEI and in fact are simply plotting energy intensity and calling it ERoEI. Lambert has not shown a plot of HDI versus Energy Intensity; I suspect that chart would be identical or near identical to the charts she has shown of HDI v EROEI. The authors are experts on this subject and there is a lot of background to the analyses. I’d welcome comments on this.

      2. Daniel Weißbach, et al. ‘ The EROIs of Power Plants – why are they so different? is very interesting, IMO. I’d like to hear comments and discussion from others about the methodology, because it is differences in methodology and assumptions that are reason for the large differences in ERoEI estimated by different authors.

      The second last slide summarises the ERoEI for the different technologies:
      • Wind and solar: 1-4
      • Fossil fuels: 30
      • Hydro: 35
      • Nuclear (today’s LWRs): 75
      • Nuclear theoretical limit: 10,000

      Weißbach includes his spreadsheet here:

      Also see other EROEI presentations linked in my first link above.

  17. Leo Smith says:

    Well I walked this pat5h when doing ‘Limitations of renewable energy;’ and concluded that costs (renewables + storage) > cost (renewables) > cost (nuclear) and therefore concluded no sane person actually trying to de-carbonise an economy would actually throw money at it.

    Either I was wrong, or they truly are insane, or they are not actually trying to de-carbonise economies.

    In fact I have invented, or perhaps dug up from dim recesses of memory, a term for what they are doing: Cosmetic solutions. They dont want to really de-carbonise anything. They want to give the appearance of doing something, because that solves the political problem, and since anthropogenic climate change itself is only a political problem, the job is done.

    No one is actually in charge up there. No one at all.

  18. roberthargraves says:

    Great graphic that I will use (with references) in my own posts.

    It’s maddening that people (especially politicians) are so ignorant of topics like:
    * the cost of wind and solar
    * the impossibility of adequate, economic energy storage
    * the harmlessness of low dose radiation
    * the benefit of vaccinations
    * the benefit of genetic engineering

    Batteries are no where near capable enough to save energy for sunless and windless times. Quoting Bill Gates, all the world’s batteries could only supply all the world’s power for 10 minutes. New battery technology is expensive and inadequate. Elon Musk’s new Gigafactory would have to make batteries for a thousand years to store one day’s electricity needs. Even converting the Great Lakes into pumped storage reservoirs doesn’t come close to meeting US power needs.

    Compressed air energy storage has been demonstrated. Page 163 of my book outlines the efficiency of the CAES plant in Tennessee, which compresses air, stores it in an underground cavern, then reheats it with natural gas as it is expanded to power turbines. For 1 kWh(e) output, the CAES requires 0.82 kWh(e) input, plus 1.34 kWh(t) from natural gas that could have generated 0.80 kWh(e) directly in a CCGT.

    For chemical energy storage, besides H2 and CH4, one can consider NH3, which doesn’t need a carbon source and doesn’t need high pressure storage. Our ThorCon MSR, designed primarily for electric generation, can generate electric power at 3 cents/kWh. The reactor achieves a 704C molten salt temperature. It’s not hot enough for direct hydrogen dissociation from water via copper-iodine process, but someone here may know of a high temperature electrolysis cycle that would work.

    Here’s where I work…

    • Peter Lang says:

      Robert Hargraves,

      Can you please tell me which plants have been generating electricity for 3c/kWh? How long have they been demonstrating this for? Can you provide a link to annual reports listing the actual electricity output from these plants and the actual annual costs?

      • mark4asp says:

        I think 3c/kWh was an estimate produced by a team of engineers they hired to do an independent feasibility study. No actual molten salt reactors exist yet. ThorCon: (31 min video)

        • Peter Lang says:


          I’ve been trying to encourage Robert Hargraves (who has done fantastic work) to stop using the wrong verb. It is misleading, misrepresenting and gives people and easy to discredit all the claims. People read it, find it’s not true and then tend to dismiss anything else said.

          • roberthargraves says:

            I think you are referring to this sentence I wrote: “Our ThorCon MSR, designed primarily for electric generation, can generate electric power at 3 cents/kWh.” I think it’s a fair statement because “can” means “has the potential to”. No ThorCon plant is in operation yet; we are planning the prototype for Indonesia. We’ve done cost analyses many times. This year-old document illustrates bottom-up cost calculations starting on page 69, but you have to slog through it.

          • Peter Lang says:

            Robert Hargraves.

            I think it’s a fair statement because “can” means “has the potential to”.

            No it does not mean that at all. It is misleading and dishonest claim. Solar advocates could equally say “solar power can provide baseload power cheaper than nuclear”. In fact, some of them (even professors) been saying it for 25 years. It’s dishonest.

            Furthermore, you frequently claim that power from thorium reactors is cheaper than coal. That is not a fact. It’s a claim by proponents.

            This sort of misrepresentation is extremely damaging to the credibility of those involved, IMO.

          • Leo Smith says:

            ‘can’ implies ‘has done before’ ‘Could’ implies ‘might be able to’

            Stop weaselling Robert.
            If sensible approaches to regulation and radiation were indeed taken any nuclear reactor should be able to beat 3c/kWh.

  19. mark4asp says:

    I calculated Britain would need 17.5 TWh of storage to buffer a wind-powered electricity grid. An impossibly large figure. None of these technologies can economically meet that scale. Not even pumped storage.

    • Isn’t there already 220TWh of hydro storage capacity in Europe alone?
      And an additional 150GW of firm capacity?

      Developing additional pumped hydro schemes at existing sites/reservoirs is just too expensive at this point.
      Existing storage is underutilised due to lack of transmission.

      • mark4asp says:

        Hydro storage is not pumped storage. How do you think Sweden and Norway, Austria, Switzerland, … will feel when you tell them their electricity systems no longer belong to them because Europe wants to take it over for our common good? I don’t think they’ll be too pleased.

    • Peter Lang says:


      Thank you for that estimate. It is double the 7.9 TWh ERP calculated for worst 3 weeks in 2012 for a 1:1 mix of solar and wind to supply 100% of GB’s electricity – see Figure 10 here and text for explanation:

      I wonder what the explanation for this factor of 2 difference is? Is it mostly due to the benefit of having both wind and solar (in deep winter)?

      • mark4asp says:

        How much solar is produced when it snows across Britain in deep winter?

        I just wanted to keep it simple to find a ball-park figure, just for myself really, because there were hordes of greenies telling me that mass energy storage was just a breeze.

  20. Nigel Wakefield says:

    I’ve been toying with another idea for pumped storage…

    We have massive salt cavities currently used for nat gas storage at up to 2 km underground – that’s a huge amount of head; up to 4 times more than at Ffestiniog, with commensurate increase in power.

    Would it be possible to re-work some of these caverns (or leach new ones) to act as the lower pond for electricity storage? Volumetrically, they are huge, many times the capacity of Dinorwig’s Llyn Peris lower pond….

    Obviously there are a huge number of problems; filling them full of water would have the effect of incrementally leaching the cavities, so some kind of membrane would be required to stop this. I’m thinking maybe some kind of sprayed polymer… no small task, I appreciate….

    Secondly, the cavities would have to remain pressurised when empty of water to prohibit salt creep (i.e. deformation leading to compromising the structural integrity of the cavity). This could be accomplished by compressing air – simply stopping as much air coming out volumetrically as water going in…. would this have an effect on power output when filling? the compressed air could be used as incremental power output when water is flowing in… though it would likely be insignificant relative the hydro output….

    Thirdly, how the hell do you get a massive hydro turbine 2 kn underground to maximise head potential, and be able to access it for future maintenance. I suppose we have the experience in such engineering feats through Crossrail and the Channel Tunnel, but it would be some task to drill a shaft of the diameter required and then retrieve the bore-machine when the job is done.

    Fourth: how to pump out the water when the cavity is full. Normally this would be done by reversing the turbine, but that would entail placing it near the the floor of the cavity rather than at the bottom the shaft/top of the cavity…. again, I guess water evacuation could be accomplished by air compression…..

    Lastly, the water source for the upper pond…. this seems relatively trivial considering the locations nat gas storage facilities like Hornsea and Aldbrough… they are right next to the North Sea… a limitless source.

    Gas storage economics are aweful at the moment, facilities are struggling to make money. – 33% of the withdrawal capacity at Hornsea was mothballed last year…. Given that much of the infrastructure is already there (the cavities) I wonder whether the owners (SSE and Statoil) would look at a feasibility study to convert some of the caverns to pumped hydro storage??

    Total cavity space at these two facilities is in excess of 630 million cubic metres, compared to the roughly 7 million cubic metres at Dinorwig. Not even allowing for the far greater head we’re talking about something in the region of 15 GW of output capacity. Simplistically, with 4x the head, we could be talking about multiples of that number…. far more than required. It would therefore make sense to extend the duration of the production cycle by utilising much smaller capacity turbines and much lower flow rates than at Dinorwig (less capex for shaft-drilling due to smaller diameter bore, smaller turbines are presumably cheaper, etc). This would have the effect of making such a facility less of a diurnal storage facility and more of a longer term type plant though still capable of a huge amount of instantaneous response when/if required. Perfect for profiling nuclear output and ironing out the intermittency of wind/solar.

    I like to dream……

    • Nigel Wakefield says:

      Small calculation error…. Llyn Peris at 7 million cubic metres is roughly 90 times smaller than the 630 million cubic metres at Hornsea and Aldbrough combined.

      Back of the envelope: Dinorwig can generate at 1800 MW for five hours using 7 million cubic metres of stored water: that’s 9 GWh. So theoretically, 630 million cubic metres of storage would give 810 GWh of storage capacity and an absolutely vast potential power output, substantially higher than the 15 GW I mentioned above – either way, a lot more than we need.

    • Euan Mearns says:

      Flat-land Large-scale Electricity Storage (FLES)

      It ain’t cheap.

      • Nigel Wakefield says:

        True, but in my pipe-dream, the upper and lower reservoirs are already there, and the turbines (and therefore the shafts) are much smaller leading to a much lower cost. So, certainly not cheap, but I’d venture much cheaper than excavating a few million cubic metres of limestone from 1.4 km under the surface…..

        • Nigel Wakefield says:

          I see Phil Chapman beat me to the punch with regards using salt cavities for pumped hydro storage on the FLES thread – my apologies to him.

          Seems all I added was a site where it could be done…….

  21. Pingback: Is large-scale energy storage dead? | Climate Collections

  22. robertok06 says:


    unless I’m missing something (busy with a conference) I cannot understand the only 8 TWh of storage needed to convert Greman PV into dispatchable energy.
    8 TWh for Germany is less than 6 days’ worth of consumption… (560 TWh/365 days=1.5 TWh/day average, but often more during cold months) and PV in Germany produces virtually NOTHING for 4 full months, November to February.

    PV in Germany will go down in history books only as an ill-defined experiment in social engineering.

  23. Euan Mearns says:

    Coire Glas (that massive and puny beast still waiting for investment) frames the scale of the problem quite well:

    Vital statistics

    Information is from this non-technical summary from SSE.

    • Generating capacity = 600 MW
    • Storage capacity = 30 GWh
    • Generating duration at capacity = 50 hours
    • Cost £800 million
    • 5 years to build
    • 150 workforce during construction
    • 12 permanent jobs

    This is the equivalent of a large combined cycle gas turbine with capacity to run for a little over 2 days before needing to be recharged.

    A massive but puny beast

    The idea is to pump water into the reservoir when it is windy. The UK wind carpet recently produced 6GW peak output and so let’s assume that 3 of those 6GW were used to pump water into Coire Glas and other such schemes, and 3GW got fed directly onto the grid. If we are to have a renewables based system that can run independently of fossil fuel back up then it needs the stamina to survive a 7 day lull in the wind. So what we need to know is the amount of storage for 3GW of supply to run continuously for 7 days. This also assumes that we had 7 days producing 6GW of wind beforehand to fill the reservoirs – and we are still light years away from achieving that!

    3GW * 24 hours * 7 days = 504 GWh of storage

    That is 17 times greater than Coire Glas and 3 GW is only about 5% of UK peak demand. Coire Glas, therefore, is simply window dressing in efforts to “Green” UK power supply with pylons, turbines and dams.

  24. Leo Smith says:

    If you could by a rechargeable battery for a 10 pounds, that cost you 15p to recharge it, or a fully charged primary battery of the same capacity for 8p that needed a 10 pound converter to produce the same output, which would you pick?

    The latter of course being the nuclear option 😉

  25. Isn’t there already 220TWh of hydro storage capacity in Europe alone?
    And an additional 150GW of firm capacity?

    Developing additional pumped hydro schemes at existing sites/reservoirs is just too expensive at this point.
    Existing storage is underutilised due to lack of transmission.

    • Isn’t there already 220TWh of hydro storage capacity in Europe alone?

      According to this Statkraft article indeed there is.

      The problem with the 220TWh estimate, however, is that it represents the total amount of energy retained behind dams in conventional hydro facilities, mostly in Norway, and almost all of this energy is consumed domestically. Little space is available for long-term storage of wind or solar. As to how much wind and solar energy Norway’s reservoirs might ultimately be capable of storing I performed a detailed analysis here:

      And came up with the answer “not very much”.

      • Sven says:

        Well, you suppose in your text that all places in Norway wher dams can be built are already utilized. Which is not correct, since requirement for pumped storage is much lower towards topography than run of the river storage dams.
        For the latter you need a steep valley to have enough height ,a valley that is narrow enough to build a dam, and a river with a lot of water.
        The first to are usual situations in steep mountains like Norway or the Alps.
        But most of these steep valleys are high up in the mountains, and there is low or no water running in them.
        For pumped hydro this is enough if it replaces water losses, or if the valley is above the existing dams. There are enough uninhabited valleys in high areas (uncomfortably cold and not usable for tourism, and mostly without plants) in Norway as wall as in the Alps. You can Ask Statkraft or TIWAG about this for example) The only limit are the price spreads which are not high enough at the moment.

        Or if you simply connect the dams along the same valleys, or in neighboring valleys on different levels.

        • robertok06 says:

          Large-scale pumped hydro in Norway to make up for the deficiencies of EU’s wind and PV is a dead horse already… as many studies show that past a given level of penetration it will become impossible to sustain economically FOR NORWAY, and therefore, since Norway is not a EU member country obliged to follow the diktats from Brussels, it won’t happen.

          Intermittent renewables will never subsitute FF or nuclear dispatchable power stations, it is physically, economically, socially, environmentally, etc… NOT sustainable, and therefore it won’t happen.

          Let’s face it and think about/propose viable, realistic alternatives, or face the consequences collectively.


        • nukie says:

          Well there seems to be a diffference between te economic of pumped storage, and vacuum techology of fusion reactors, otherwise I can not explan Robertoko’s comment.

          Norway is the driving power behind the interconnectors, because they allow them to earn money by trading electricity. As simple as that.
          Same as Austria and Swizerland are doing for a century.

          As soon as the price spread between low electricity costs ( to low demand for baseload nuclear power, high wind, high solar irradiation) and high prices (Demand higher than nuclear capacity, low wind, low solar irradiation compared to demand ) exceeds a certain level,

          As soon as the price difference finances additional Turbines, or also new Dams in mostly dry valleys above existing storage lakes, they can be built and earn money for the country where they are located.
          This is why Austria presses a lot that the North-South connectors in germany are exmpanded a lot. They could already make good use of more GW electric power at times of high wind and low electricity prices, but can not get them due to limited grid (although power exchange between Austria and Germany already is much stronger than e.g. between Scotland and England, multiple times stronger), and they’d love to add more Turbines and storages, with the possibility to earn money. They think that with a expansion of renewables in germany , volatility of prices will rise once e.g. PV is stron enough not just to remove the day peak in residual demand, but to make it a regulad demand valley during half of the year at least, acompanied wit times of stronfg wind in winter. It’s just a question that price differences are high enough and grid is strong enough.

  26. robertok06 says:

    “Well, at some point something obviously has to give, but what, where and when is the question.”

    Well… Mother Nature, by definition, always wins… easy… so the loosers is us, mankind.
    It will not be the first time in history that mankind has made really bad choices, meaning that we are not even living a one-of-a-kind event, it is just sheer (collective) stupidity taking its toll.


  27. robertok06 says:

    “Isn’t there already 220TWh of hydro storage capacity in Europe alone?”

    Not to my knowledge!… where did you get this datum from?

    A detailed study of Eurelectric, I think it dates back to 2011, detailed each EU (and non-EU, like CH and NO) country, even included Turkey within Europe, and got a smaller amount.

    Here it is a similar one, same source:

    … fig.8… total deliverable energy by pumped hydro, existing one… orders of magnitude BELOW what would be needed in case of massive use of intermittent/seasonal renewable sources.

    The POTENTIAL is of the order of what you’ve mentioned, but this means using all available/suitable mountain valleys of every single EU and non EU country would get flooded (Norway and Turkey by themselves make more than 1/2 of the total potential).
    Irrealistic to say the least, a pipe dream to say the best.


    • Got it from the Statkraft PDF Robert mentioned above and it’s in the ballpark I learned about while studying at TU Vienna. The potential is much higher.
      In a Gregor Czisch lecture the data suggested that a European grid with mostly wind energy would not need any further hydro storage. In an extreme case Danish offshore wind could supply the whole of Europe with power.
      Saw data about storage in Switzerland and Austria which is much underutilised.
      Projects like Grimsel 3 are just not needed at the moment.

      From what I have seen I doubt Europe is clueless about what they are up to with RE.
      I’d rather say they did their research very well.

    • Peter Lang says:

      From the Energy Storage Association says a total of 120 GW of pumped hydro storage capacity either in operation or under construction:

      Globally, there are 270 pumped hydroelectric storage (PHS) stations either operating or under construction. This represents a combined generating capacity of over 120,000 megawatts (MW). Of these total installations, 36 units consist of variable-speed machines, 17 of which are currently in operation (totaling 3,569 MW) and 19 of which are under construction (totaling 4,558 MW). …

      ROAM report on Pumped Storage modelling for AEMO 100% Renewables project Figure 1 (attributed to EPRI) shows that 99% of global electricity storage generating capcity is pumped hydro

  28. For those interested in learning more about the problems of integrating large amounts of wind and solar with the grid without having things fall off or catch fire there are a couple of articles written by “Planning Engineer” over at Judith Curry’s blog that are well worth the read.

    • Willem post says:

      Thank you for these two articles.
      They are the best and most easily understood summaries regarding the adverse impacts of wind and solar energy on grid stability.
      As wind and solar increase, the instability issues increase exponentially, because of lesser remaining synchronous rotational inertia.
      That is one of the main reasons for having at least 50% nuclear, with about 20% more from other synchronous sources, leaving at most 30% for the bad actors, les enchants terrible.
      I will use them as references in my articles.

  29. Olav says:

    Invest Yr Days Prod Cost a kWh Eff %
    PHS 605000000 50 365 9100000 0,00364 70
    Rail Wagons Ares 55000000 35 365 12500 0,34442 74
    Large Led Kodiak Al 4000000 3 365 1000 3,65297 65
    CAES Texas 50000000 15 365 3000000 0,00304 80
    Heat to Heatcrt to Heat 50000000 50 365 1250000 0,00219 95
    Heat to Heatcrt to El 50000000 50 365 500000 0,00548 40
    My cooking storage 600 50 300 3 0,01333 50
    Diesel to Heat 0,8 1 1 9 0,08889 90
    Diesel to El 0,8 1 1 3 0,2667 30
    Battery + Inverter 7000 10 365 5,6 0,3425 65
    Battery + Inverter 6000 10 365 5,6 0,2935 65
    Battery + Inverter 5000 10 365 5,6 0,2446 65
    Battery + Inverter 4000 10 365 5,6 0,1957 65
    Battery + Inverter 3000 10 365 5,6 0,1468 65
    Battery + Inverter 2000 10 365 5,6 0,0978 65
    Battery + Inverter 1000 10 365 5,6 0,0489 65
    Biogas Denmark 28000000 1 1 111000000 0,2523 90

    I tried to use Wilhelm easy formula “Assuming one cycle per day, ” A quick estimate cost of storage is $55,000,000/(35 y x 365 d/y x 12,500 kWh) = 0.344 c/kWh.” for different storage alternatives.
    For all above is O & M, electricity purchase & financial cost ignored. The cost a kWh is only looking at investment and cycles expected. For me it looks as CAES is most promising compared with PHS which I consider as the king. Even an unrealistic extremely low cost of 100 $ a kWh including inverter makes battery storage 14x more expansive as PHS
    Large led acid batteries in Alaska was limited to 1000 cycles making it extremely expansive.
    Batteries are only for short time emergencies’ like an UPS.
    All is for daily cycling as seasonal storage is impossible.
    UK has a little solar and lots of wind especially at winter making seasonal storage of solar power unnecessary anyway. But the “lulls” may last for a week or more and creating storage for that is almost impossible. Interconnectors will help but a lot of standby gas/coal power is still needed.
    Nuclear as (a lot of new ones preferably) as smaller units is the least costly but nuclear is also depending on storage as the first PHS were made to assist nuclear.

    The table on top may come out unreadable so moderator is free to delete all

    • Peter Lang says:


      I tried to use Wilhelm easy formula “Assuming one cycle per day, ” A quick estimate cost of storage is $55,000,000/(35 y x 365 d/y x 12,500 kWh) = 0.344 c/kWh.” for different storage alternatives.

      This is an estimate of the energy storage’s addition to the cost of electricity. It is not the capital cost of energy storage.

      Also, not that the assumption of one full cycle per day for 35 years is nowhere close to being correct for weather dependent renewables..

      • Olav says:

        Yes it does not take in capital cost & O & M : Anyway is capital cost increasing the “cost of storage” with the same percentage as durability and an overly optimistic cycling is factored in. This is just a way to compare different storages against each other. I will believe that Operation cost of rail cars on a slope is very high while batteries has zero cost until something happens and then…
        The Energy Nest storage was new for me until a year ago. Siting, footprint, durability, users beyond power producers and reasonable cost with low operational cost is interesting.

        Rated / maximum capacity 1.25 GWhth / 1.65 GWhth
        Volume / mass of storage medium (Heatcrete®) 30 800 m3 67 700 ton
        Footprint 4 400 m
        Height 14 m
        Procurement and construction cost estimate USD 50 million

  30. euanmearns says:

    Is large-scale energy storage dead?

    Alternative title:

    Was large scale energy storage ever alive?

    Well of course it was and still is….

    500,000 MJ/ Kg of natural uranium. Does anyone have time to convert that to GWh? Accounting of course for all energy losses along the way.

    • 500,000 MJ/ Kg of natural uranium. Does anyone have time to convert that to GWh? Accounting of course for all energy losses along the way.

      one ….. kilogram of U generates 37 MWh of electricity .

      I’ll let you account for the energy losses along the way.

      • stone100 says:

        Am I right in thinking that the reason why David Mackay thinks mined Uranium will last longer than your ( ) estimate is because David Mackay was assuming that if prices went to >$130/kg, then phosphate would be mined specifically as a source of Uranium? David Mackay said phosphate deposits hold 22 million tonnes of Uranium (4/5th of minable uranium resources) whilst your post was factoring in just the 0.9 million tonnes of Uranium that would come as a byproduct up to 2050 if phosphate mining wasn’t ramped up beyond 200 million tons of phosphate rock per year.

        • Peter Lang says:

          The price of uranium is irrelevant in the analysis of how long uranium will last. The reason it is irrelevant is that mining practices and exploration practices are continuously improving. Consider how they have improved over the long term (thousands of years, hundreds of years and during the past century) and project forward.

          A way to estimate how long uranium will last is to estimate the mass of uranium that is likely to be mineable eventually – e.g. 100, 200, 500, 1,000, 10,000 years from now. We can estimate the mass of uranium in deposits with various concentrations. When you do this calculation it turns out there is sufficient uranium in the upper continental crust at concentrations likely to eventually be mineable to supply primary energy for a population of 10 billion people consuming the same per capita energy as the US does now for ….. >10,000 years. That’s not including uranium in sea water or thorium. And then there’s fusion.

          In short, the world is not short of energy. It’s just that progress is blocked and has been for 50 years by those who call themselves ‘Progressives’.

        • robertok06 says:

          Concerning uranium availability and reserves…

          “A protein engineered to bind uranyl selectively and with femtomolar affinity”

          … this opens up the reservers to a couple BILLION tons of seawater uranium… enough for a couple hundred thousand years’ worth of nuclear power.

    • Syndroma says:

      500,000 MJ/kg = 139 MWh(th)/kg of natural uranium when used in thermal reactors. If used in breeders the energy content is 80,620,000 MJ/kg = 22.4 GWh(th)/kg.

    • robertok06 says:

      3.6 MJ/kWh… and then a factor of 0.35 to account for the Carnot losses… approx 10 MJ/kWhe, then… a factor of 10 less… ~50,000 kWh/kg.

  31. gweberbv says:

    It is always nice to have facilities for large-scale energy storage in the grid. But it is really needed now? Or in 10 years? If one looks at the continent, production by (intermittent) renewables is still just a drop in the sea of FF-based electricity production. This means, once one solves the grid bottlenecks, one will always find a FF plant somewhere that can deliever. And vice versa production by PV and wind can always be transported to a place where a FF plant can ramp down. And fighting the grid bottlenecks is far cheaper than investing into local storage projects.

    This is the situation now and for the years to come. If the goals that are stated for 2050 should be reached (which I doubt being a concern of todays decision makers), at a certain point penetration of (intermittent) renewables on the European level will be such high that the lack of storage options becomes an issue. But – at least in my opinnion – we are still far, far away from this point.

    • I don’t know how far away we are from the point where the lack of storage options becomes an issue. It will vary from place to place. But for some time now we’ve been pointing out that high levels of renewables penetration can be achieved by using fossil fuel plants to balance intermittency provided one is prepared to accept the inefficiencies involved, such as high levels of renewables curtailment, low utilization of FF plants, high ramp rates and high costs. In the absence of storage this is in fact the only way of achieving any meaningful percentage of renewables generation. But why anyone would want to pursue it while the option of expanding nuclear remains open is a mystery to me.

      • Dave Rutledge says:

        Hi Roger,

        At this stage, the storage is subsidies and crony capitalism in its most extreme parasitic form. That is certainly the way it is playing out here in California. In this day and age, the grid should be balanced with natural gas.

        In the long run, I don’t know. The Germans produce a massive amount of biogas, which might work as an alternative to natural gas.


      • gweberbv says:


        as long as the public is much more concerned about radioactivity than about other things that are/could harm the people, investment into new nuclear power plants is basicly off the table. If those fears are based on realistic assumptions, is irrelevant. Major parts of western politics these days is dominated by completely irrational fears/agendas. What happens in peoples minds has consequences – if it is based on year-long studies or on simply believing the stuff you heard this morning on your favourite radio show.

        Regarding the inefficiencies induced to electricity production by intermittency of renewables: Expensive storage is much more inefficient (on the scale necessary to transform the major part of PV and wind into baseload-type production profiles) than all other solutions to this issue.

        • Peter Lang says:


          as long as the public is much more concerned about radioactivity than about other things that are/could harm the people, investment into new nuclear power plants is basicly off the table.

          That’s a circular argument. Anti nukes and RE advocates, like you, spend their time trying to scare the public about nuclear power and radiation and distorting the truth about nuclear and renewables (including trying divert attention from the topic of this thread). Then they use the fear of nuclear that has been generated by the anti-nukes as an argument for why nuclear is unacceptable tot the public and can’t progress.

          That’s why I keep saying there will be slow progress until those who call themselves “Progressives” stop blocking progress.

          I’d urge you to separate your emotional arguments from the rational analysis. Deal with them as separate issues. If you were rational and logical, you’d acknowledge that:

          1. yes, nuclear is potentially by far the best alternative for providing clean energy for a world with 10 billion population effectively indefinitely; and

          2. Yes, renewables cannot make much of a contribution to supplying the world’s energy, they are ridiculously expensive and probably always will be. By wasting money on them to satisfy the irrational, emotive, ideological beliefs of the so-called “progressives” global economic growth is being retarded. Therefore, much of humanity will be kept in poverty longer, standards of living will improve slower than they otherwise would, life expectancy, health, education, infrastructure will all improve more slowly.

          I’d suggest you change from your dishonest scare mongering about nuclear and start telling people the truth about the enormous damage the ideological obsession with renewables and anti-nuclear popaganda is doing to livelihoods of this and future generations.

          • gweberbv says:


            it was Roger who brought up the NPP issue, not me.

            I agree that nuclear power is a wonderful technology. But that it is having a very bad press recently is for sure not my fault. Look at this:
            And this:
            Why should a society be enthusiastic to accept such things? For comparison: When the third runway of Frankfurt airport was build a few years ago, a major chemical factory located nearby was forced to move away because risk estimates yielded – I can’t remember exactly – a 1/1000000 probability for an airplane crashing into it.
            While there is no viable alternative to air traffic, nuclear power is just one source of energy among many others (will be different in hundred years, when most FF are depleted).

            Moreover, your claim that investments into renewables are retarding economic growth is utterly naive. To put this on the table, you must assume that the people that are producing wind turbines are not available for other tasks. That the glass that is used for the PV modules is not avaiable to build windows, etc. Have a look at reality! Since the economy crisis of 2008 we have an underutlized work force of dozens of millions relatively good educated people all around the world. We have a huge underutilization of nearly all production facilites worldwide. We have billions and billions of money craving for investment opportunities but ending up wth buying government bonds for near-zero interest rates. Renewables are not eating anyone elses cake. In fact, they (as all the other stimulus-like government measures) help to stabilize the economy in today recessive environment.

          • Peter Lang says:

            Why should a society be enthusiastic to accept such things (i.e. NPPs)?

            That’s a really dumb question. Simple answer:

            1. It is the safest way to generate a large proportion of the electricity we need.
            2. it can provide all the energy need, and do so for thousands of years – renewables cannot,. they are not sustainable. That’s what this thread and links included on it show so clearly.
            3. Even with all the impediments imposed on it by the irrational anti-nukes, like you, it is still the cheapest technology for decarbonising electricity and the fastest way to make deep cuts (for those concerned about GHG emissions)
            4. Increasing a country’s ERoEI increases living standards.

            As I said, your questions is dumb or your are blind to everything you’ve been told in blog posts and comments on Energy matters.

      • It doesn't add up... says:

        I’m wondering just how much flexibility the UK grid has: I took a look at the data on forecast wind output and actual output collected on Gridwatch. Plotting both as histograms of output, it appears that when the forecast is high (above 6GW) it is probably typically curtailed.

  32. stone100 says:

    I’d really welcome a thorough tire-kicking appraisal of liquid air energy storage. That still seems to me the least unrealistic technology so far. I guestimated that to store 30GWx24h ie 720GWh would take 48 tanks each of 190,000m^3. Such cryogenic tanks are used already to store LNG and cost £250m each. I’m not saying it’s cheap or easy but it seems the least bad option if we need that amount of energy storage.

  33. Peter Lang says:


    The original of this chart you included in the ARES thread is from the Electricity Supply Association . I used to have access to ESA but don’t any longer. They also have a chart showing those technologies and the cost per kWh energy storage capacity versus cost per kW generating capacity. If you or Euan have access to the ESA web site, it might be of interest for followers here to post that chart on this thread (if that is allowable).

  34. Peter Lang says:

    Correction: I meant Energy Storage Association. Here is the link:

  35. “Relative to California’s 50GW peak load 1.3GW can hardly be described as “huge””

    Funny how the author – quite rightly – criticizes others for not distinguishing between GW and GW-h and then proceeds to do likewise. 🙂

    In motor cars, we don’t have that problem as it is horse power and litres.

  36. Daniel says:

    The World’s Largest NAS Battery Installation Commences Operation
    Short Installation Period Achieved through Containerized, Compact Format

    50 MW / 300 MWh

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