The DECC Pathways Calculator – A False Prophet

In a comment on the recent power-to-methane post I made the following observation:

It would be an interesting exercise to take a high-renewables-penetration DECC scenario that meets UK emissions targets, convert it to hourly generation by factoring actual Gridwatch generation and compare it to demand for, say, 2013 or 2014. I’d be willing to bet the UK would be freezing in the dark for much of the time during the winter.

Well, the interesting exercise is now complete and this post documents the results. They are based on a DECC Pathways Calculator scenario that meets the UK’s 80%-by-2050 emissions reduction target and uses the Centre for Alternative Technology’s (CAT) 100% renewables generation mix listed in the power-to-methane post. And to eliminate any suspense as to the outcome Figure 1 previews what we get when we compare February 2050 generation for this scenario with February 2050 demand, with both projected using factored February 2013 data from Gridwatch and other sources:

Figure 1: Generation deficits using DECC 80%-emissions-reduction-by-2050 and CAT 100% renewables generation mix scenario, February 2050 simulated hourly data.

I would have won my bet.

To construct the scenario I began with the DECC Pathways Calculator, which allows one to juggle 42 different input variables until the desired goal of an 80% reduction in UK emissions by 2050 is achieved. It took me a little while to get to this point, but in the process of getting there I noted a few interesting features that I will mention before proceeding. According to the DECC Calculator:

• Major reductions in emissions from transportation, heating etc. are needed to meet the 80% target. Simply decarbonizing electricity generation doesn’t do it.

• The biggest emissions-reduction bang-for-the-buck comes from expanding nuclear.

• Biomass generation significantly increases CO2 emissions.

The scenario I eventually developed is summarized in the Figure 2 screenshot and in this link which shows the scenario with the appropriate boxes clicked. The columns on the left show how I had to redline many of the demand side options such as transportation and heating to get to the 80% target, the column in the middle replicates the CAT energy mix reasonably closely and the redlined variable at the upper right is, unsurprisingly, energy storage:

Figure 2: The DECC 80%-emissions-reduction-by-2050 scenario

The CAT scenario contemplates that annual UK electricity generation will double between 2013 and 2050 from 359TWh to 738TWh. The added generation goes mostly towards the electrification of transport, including 100% zero-emissions vehicles (presumably EVs), 100% electrified railways and 50% electrified buses.

Having developed the scenario the next step was to convert it into 2050 electricity generation relative to the 2030 CAT generation mix shown in Figure 3:

Figure 3: The CAT 100% renewables generation mix

To do this I again used February 2013 as my “average winter month” and assumed that the wind, tide, solar etc. conditions in that month would be duplicated in February 2050 and  that the shape of the demand curve, although not its amplitude, would be the same. The scaling factors and other assumptions used to derive the generation numbers are detailed below:

Demand: February 2013 Gridwatch demand was scaled up by a factor of 2.06 (738TWh annual generation in 2050/359TWh annual generation in 2013).

Wind: February 2013 Gridwatch wind generation (offshore + onshore combined) averaged 2,053MW. With the CAT energy mix offshore+onshore wind averages 68,055MW. February 2103 wind generation was therefore scaled up by a factor of 68055/2053 = 33.14.

Hydro: February 2013 Gridwatch hydro generation averaged 412MW. With the CAT energy mix it averages 937MW. February 2103 hydro generation was therefore scaled up by a factor of 937/412 = 2.28.

Geothermal : The CAT scenario calls for ~24TWh/year of geothermal, which works out to an average of ~2,800MW. This was input as constant baseload generation.

Solar PV: Gridwatch gives no solar generation data, so I used the February 2013 data for France taken from the PF Bach data base (astronomical noon in France occurs on average only about 15 minutes beforeastronomical noon in UK). Solar generation in France in February 2013 averaged 381 MW while the CAT scenario calls for an average of 6,794MW, so the February 2013 data were scaled up by a factor of 6,794/381= 17.83.

Tidal Power: Tidal power causes difficulties because there are no large-scale tide power generation records to factor up. Eventually I settled on a spring-neap tide approximation based on a peak spring tide on February 12th. I had insufficient information to estimate semidiurnal variations, so the approximation implicitly assumes that these are canceled out by mixing output from tidal plants where tide times are three hours apart, as discussed in the Swansea Bay post. Also as discussed in the same post, however, they almost certainly won’t be, so this gives tidal power a break in that it makes it look a lot easier to match to demand than it really is.

Figure 4 shows generation from the five energy sources listed above during February 2050. Generation is dominated by wind with relatively minor contributions from solar and tidal. Geothermal and hydro barely lift off the X-axis:

Figure 4: Generation by source, February 2050 simulated hourly data

Figure 5 sums generation from all five sources and compares it with demand. Note that generation and demand are the same at 58TWh for the month:

Figure 5: Total generation versus demand, February 2050 simulated hourly data

And Figure 6 plots generation surpluses and deficits relative to demand:

Figure 6: Surpluses and deficits, calculated as generation minus demand, February 2050 simulated hourly data

FIgure 6 doesn’t look good from the standpoint of matching generation to demand, but we haven’t yet allowed for storage. My scenario uses DECC Level 4, the largest storage option, in which DECC assumes:

that by 2050 the UK has 20GW of storage, with a storage capacity of 400GWh, and 30GW of interconnectors. This level also assumes that around 75% of electric cars allow flexible charging for co-ordinated demand shifting.

I gave DECC’s storage option two breaks. First I assumed that output from storage isn’t limited to 20GW – it can be whatever it needs to be to follow demand. Second I assumed that all of the electric cars used for co-ordinated demand shifting will be available at the time they are needed and not marooned somewhere with dead batteries. Using the 400GWh of storage capacity to balance the surpluses and deficits shown on Figure 6 now gives the energy-in-storage plot shown in Figure 7. There is no energy left in storage for half the time:

Figure 7: Gigawatt-hours in storage, February 2050 simulated hourly data

After allowing for the load-following contributions that storage is able to make we are left with the generation deficits shown earlier in Figure 1, which is reproduced below for reference as Figure 8:

Figure 8: Generation deficits, February 2050 simulated hourly data

What happens to the generation surpluses? Those that can’t be fed into storage have to be curtailed, resulting in curtailments aggregating 9.8 TWh, or 17% of the total power generated in the month (Figure 9):

Figure 9: Surplus power curtailed, February 2050 simulated hourly data

But DECC still has one last string to its bow – its 30GW of assumed interconnector capacity. With a cold winter anticyclone covering a renewables-heavy Europe no one will of course have any power to spare, but we will nevertheless assume that the UK’s helpful neighbors somehow scrape together enough to export up to 30GW to UK whenever the UK needs it. Adding this imported power gives us Figure 10:

Figure 10: Generation deficits after allowing for 30GW imports, February 2050 simulated hourly data

And the lights still go out; just for not as long.

Time to sum up. Here is an example of how the DECC Pathways Calculator manufactures a pathway to a green, sustainable future that looks good on paper but won’t work in practice, and it’s far from being the only one. In fact no pathway that combines high levels of intermittent renewables generation with inadequate storage is going to work in practice, and because the DECC Calculator conveniently ignores this flaw in its logic it gives results that can only charitably be described as misleading.

Is there any way the DECC Calculator could be modified to give more objective results? Indeed there is. It could perform an analysis like the one I perform above for each scenario submitted, which is not beyond the capabilities of an Excel spreadsheet. It is, however, unlikely that it ever will, partly because the vast majority of renewables-heavy scenarios would flunk this test and partly because the 80%-emissions-reduction-by-2050 target enshrined in the Climate Change Act implicitly assumes that the UK can solve the problem of decarbonizing the electricity sector simply by throwing renewables at it, which of course it can’t.


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48 Responses to The DECC Pathways Calculator – A False Prophet

  1. Fred says:

    Interesting point is what impact self-drive vehicles will have on the equation.

    The more I look at it, the more I think owning your own vehicle will go out of fashion, with Uber like hire of a self-drive vehicle when needed (eg taxi). That gives scope for many more electric vehicles and consequent storage, all under computer control. Utilisation will increase, CO2 decrease, etc. Couple that with domestic storage (to stop the electricity companies bending you over) and some large scale storage options, and I think the world ten years hence could be very different.

    • Leo Smith says:

      Sadly when you run the numbers only one thing can save civilisation, which is intrinsically power hungry, and that is massive deployment of nuclear power of some sort or another.

      The only variable is how long people take to realise that, and the depth of damage done before they do.

      • Fred says:

        Hmm, lets do some numbers, shall we?

        1 Tesla Vehicle = 60-85kWh of storage capacity
        1 Tesla Powerwall = 10 kWh of storage capacity
        Thus for
        400GWh of storage
        we are looking ~5000 Tesla cars, or 40,000 home storage units.

        There are currently ~35m vehicles in the UK and ~230k taxies. Let’s assume that by 2050 we have just 1m self-drive electric vehicles in the UK (all those taxis, plus some second cars, etc). Thus ~0.5-1% of those vehicles could be employed, when needed, to provide your ‘get you over the line’ storage capacity. Realistically we are likely to have about 95% self-drive vehicles by then.

        That’s ignoring that domestic storage of electricity is likely to take off for all those with roof solar. If 1% of the UK housing stock (26m > 260k) had such 10kWh units, that would equal 2.6 TWh of storage. We already have half a million households with solar on the roof.

        And THEN we have infrastructure level storage options.

        In short, with the changes we can expect over the next 35 years, without everyone suddenly feeling massively environmentally aware, we could expect to be able to ride out any gray, becalmed, weeks.

        • Fred, check your sums. I think you’ll find you have slipped a few zeroes.

          • Fred says:

            Oops, yeah, MW vs GW, not awake.

            Point stands though – the scale of what’s being talked about in self-drive electric vehicles + home-level storage + infrastructure-level storage is likely to be able surpass the needed storage for these still,gray Februaries – given we are talking about 2050 timeframes. And it’s not as if it needs mass government investment – these are things that look to be happening anyway. Government nudge and keeping daft anti-regulation out of the way being all that’s needed.

          • When you add three zeros to the end of your numbers the point doesn’t stand, particularly when you aren’t going to get anything like 100% discharge capability out of your fleet of 5 million Teslas, as Willem Post points out, and when the 400GWh of storage they give you at 100% discharge capacity is totally inadequate anyway. To make the plan work you would probably need closer to 50 million Teslas. Or if you like 400 million Tesla 10kW wall units. Plus infrastructure.

            Ah! others say. But we can still do it with biogas. I did some work on that too. Arguably the most productive source of biogas energy is the humble cow, which produces enough manure to generate 3kWh/day. And how many cows would the UK need to cover the 85GW generation deficits on February 18th and 19th? Assuming 3kWh/cow/day and 100% manure recovery it works out to about 700 million, an average of about 40 cows per hectare of available agricultural land. And you can add to that the mind-boggling amount of infrastructure needed to collect the manure and transport it to tens or hundreds of thousands of biogas plants and distribute it from there to the gas pipeline network …..

            Sorry, but “solutions” like these are pipe dreams, and if the UK continues to treat them as achievable there’s no question that sooner or later, probably sooner, it will finish up freezing in the dark.

          • Fred says:


            Point still stands because the point was that developments we already expect to be happening, outside specifically energy developments, are going to be delivering more storage capacity than this DECC ‘high-renewables’ scenario. As such it’s something of a baseline case, not a massive excursion.

            One of the key aspects of making forecasts is to nail down your baseline case well (too often it’s simply viewed as ‘no change’, which is itself massively unlikely). If you take an overly reductionist view of single areas with no expected changes in anything else – you miss the wood for the trees.

            Now, personally I think sensible nukes (for preference fusion) should be part of any credible energy mix – but the fact remains that this ‘high storage’ scenario is not a ‘pipedream’.

            In reality other factors, such as the expected move to job automation and the inability of our financial system to cope are also going to come to the fore – and drown out any niche discussion of what our energy mix ‘should’ be.

          • In this post I use the DECC level 4 storage option. According to DECC level 4 describes a level of change that could be achieved with effort at the extreme end of what is thought to be physically plausible by the most optimistic observer.

            But despite being at the extreme end of what is thought to be physically plausible by the most optimistic observer the DECC level 4 storage option is still totally inadequate, as I demonstrate in the post.

            Yet still you claim that “energy developments, are going to be delivering more storage capacity than this DECC ‘high-renewables’ scenario.”

            Could you please specify exactly what these energy developments are, how they will combine to keep the lights on in 2050 and how DECC came to overlook them? And please “nail down your baseline case” with some hard numbers. Unsupported claims like “the fact remains that this high storage scenario is not a pipedream” do not contribute to the discussion.

        • Willem Post says:

          In the real world, your calculation method would not work.

          Battery capacity is much greater than its working capacity.

          It is somewhat like your car engine having a capacity of 180 hp, but most of the time its output is about 25-40 hp.

          If that number were greater, then the car life would be shorter.

          The same goes for batteries. So divide whatever capacity you come up with by about 4.

  2. Matthew Nayler says:

    Just what the planet doesn’t need – perfect conditions for a baby boom. See Alfredo Burlando, ‘Power Outages, Power Externalities, and Baby Booms’ University of Oregon, Feb 2014.

  3. Leo Smith says:

    Very interesting article on grid storage here..

    Essential summary: ‘there is no storage technology available cheap enough or energy dense enough to cope with intermittent renewables, nor is there likely to be’.

    • Rud Istvan’s article on energy storage is probably the best one out there, and his conclusion is highly relevant to this post:

      “It is very unlikely that any grid storage solution (other than PHS where feasible) could ever practically cover the intermittency of high penetration utility scale wind and solar. Utility voices (like RWE and E.ON) charged with making electricity grids work seamlessly and reliably despite ever increasing renewable intermittency burdens are only starting to be heard. Those voices are very negative. It may not be until some grid goes dark because of intermittency (as increasingly uneconomic flexed conventional generation is shut in Germany and UK) that the general public will understand. Germany, UK, and California seem determined to run this unfortunate experiment for the rest of us. One or more appear likely to succeed soon in experimentally proving the grid instability ‘blackout’ hypothesis. The question is mainly when, not if.”

      • Willem Post says:


        Fossil fuels are the host on which the parasites (wind, solar) depend. If the host weakens or gradually dwindles, a new host is needed.

        It could be hydro storage in a few cases, but all other forms of storage will be much more expensive per GWh stored.

        With hydro storage, only a part of its capacity can be used for longer term storage, as its other parts are needed for balancing.

        As an academic exercise, it would be useful to assume a large capacity of hydro storage and see how its stored energy would be affected by demand, wind and solar production, and balancing.

        That case would exist, if Denmark only had wind and solar energy and used Norway’s system for balancing.

        If solar is neglected, then existing wind energy percent can be ratio-ed up to 100%, to determine hydro storage and balancing energy flows to cover just Denmark, even during longer term periods with little wind.

        • Graeme No.3 says:

          But would the Norwegians agree to build vast amounts of pumped hydro for the benefit of the Danes?

  4. Euan Mearns says:

    Roger, allow me to summarise:

    Electricity demand to double – I broadly support electrification of transport and space heating (heat pumps) so not too much trouble with that.

    Wind capacity to go up by factor of 33
    Hydro capacity to double – more flooding of Scottish Valleys? They should try flooding the Lake District instead.
    3 GW of geothermal in a country with low heat flow
    Solar to be increased by a factor of 18 in a land where The Sun seldom shines

    So far this is totally bonkers…..

    UK Storage currently 27 GWh to go up to 400 GWh – up by a factor of 15 and V2G remains one of those fantasy storage crutches.

    Interconnector capacity increased to 30 GW to nowhere

    And after all that it still doesn’t work. Evidently we still need to maintain 50 GW of FF thermal capacity (probably more than we have today) and adding in the non-existent fantasy 30 GW of interconnector that rises to 80 GW of massive loss making reserve.

    Is there no one in government or academia understands that this is all insane?

    • Willem Post says:


      Not only what you say, but greater penetrations of variable wind and solar energy will require much greater storage capacity.

      Relying on connections to nearby grids is a fantasy, as Germany will find out trying to rely on Norway, Sweden, etc for balancing and storage its increasing RE percent.

      Modern civilization has overcooked its environmental goose, pigged out on fossil. Absent nuclear, modern civilization cannot be supported without fossil.

      There is no way what Roger describes would not increase WHOLESALE energy costs by at least a factor of 3, which will create at least a 3-fold increase on the cost of living, as OTHER minerals become scarcer, harder to get to, and more expensively to process as well.

      Any structural changes would need to be made with increasingly more expensive energy and other goods and services.

      Figure 3 shows no bio fuel contribution, which is just as well, as it is an increaser of CO2 WRT to coal, gas, and oil.

      Two thousand years ago a person was hanging on a cross. It is alleged he said: “Forgive them, oh Lord, for they know not what they do.”

      • Willem Post says:


        Here is a report that shows how the US would get to 100% renewables by 2050 and save money as well. What is not to love.

        Wind onshore…………30.9%
        Wind offshore…………19.1%
        PV solar utility………..30.7%
        CSP w storage…………7.3%

        Based on a parallel grid integration study, for peaking and grid stability, an additional 4.4% of CSP w/storage, plus 7.2% solar thermal for heat, beyond annual demand, would be needed. efmh/jacobson/Articles/I/WWS-50-USState-plans.html.

        • Willem Post says:

          I tested the integration study URL, but “page not found” showed up!!

          • Same thing happened to me.

            Stanford’s plan is in fact based on an energy storage study that’s still “in review” by them and not available for study by anyone else.

            Maybe they’ve found something wrong with it? Nah.

            They also have a study showing how the whole world can go zero carbon by 2050 ……

            I might do something on this later.

          • Roberto says:

            The Green pasdaran jacobson Is not new to this, it Is just an update review of the two-part study he published with some of the same co authors, De Lucchi for instance… It’s becoming DAU, dreaming as usual… at the same time California’s electricity cost is skyrocketing following the increased use of intermittent renewables, first of all PV.
            The paper is downloadable, for a fee, from the journal’s web site.

        • Euan Mearns says:

          The US has the advantage of 4 time zones where E-W interconnection can at least smear out peak demand and solar over supply.

          • Willem Post says:


            The US has 3 major grids with weak interconnections.

            In fact, Midwest, coal-based energy is transmitted to the East Coast in the morning while East Coast plants are warming up, as there is a one-hour time difference.

            Much of the Great Plains wind energy is also transmitted to eastward states.

            Wind patterns on the East Coast, weak to begin with, are significantly different from the Midwest and Great Plains.

            I think Andrew’s articles on this subject should be sent to Jacobson to he can learn about a different approach.

    • Is there no one in government or academia understands that this is all insane?

      Quite to the contrary, Euan. The Calculator is in fact used as an instructional tool. In 2013 DECC took it on the road in the “British Energy Challenge Roadshows”, which “present a valuable opportunity for leaders in key sectors and communities to engage with the issues of energy security and to highlight the challenge which faces us.”

      The inaugural British Energy Challenge (BEC) roadshow took place at Liverpool’s Victoria Gallery & Museum on Thursday 18 April, jointly hosted by DECC and the Liverpool City Region Local Enterprise Partnership (LEP).(The main event of the afternoon was) a demonstration of DECC’s 2050 Pathways Calculator, hosted by climate change campaigner and author, Mark Lynas, and DECC strategist, Tom Counsell. As the audience in Liverpool selected their energy pathway….

      And what pathway did Liverpool select? 430TWh/year of wind and solar and zero energy storage.

      The roadshow then went to Nottingham, Sheffield, Leeds, Birmingham, Manchester, Newcastle and Bristol, where audiences selected more similarly unworkable pathways.

      David Mackay summed up the results of the roadshows thus:

      89% of respondents said they learnt something new;
      80% of respondents said they had a clearer understanding of the energy challenge facing Britain;
      92% of respondents said they would discuss what they had heard with family/friends/colleagues/networks.

      So now there are thousands of people spreading the “we can do it” gospel while in fact we can’t, or at least not this way.

      • Euan Mearns says:

        Roger, it occurred to me after I wrote this that the pathway you tested was to deliver 80% emissions reduction. And so it may retain 20% of FF. Its maybe not the calculator that is at fault but the folks who think its OK to beef up renewables by many factors, build interconnectors and storage and still be 100% dependent on FF for some of the time and that its OK to have loss making FF plant just sitting there idle waiting for a calm spell.

        Can you say in % of GWh generation how much comes from FF backup?

        • Tricky question Euan. According to the CAT scenario all of the power is renewable, but because it’s not possible to dovetail the CAT energy mix exactly with the DECC calculator variables my DECC 80% emissions reduction scenario still includes a small amount of coal and gas, although I’ve no idea where it comes from. (I tried to remove it by clicking on different boxes but couldn’t).

        • Willem Post says:


          That is similar to the trucks, etc., of the fire department, in case there would be a fire, or for that matter, the war machine, in case there would be a war.

          Regarding the latter, that machine can keep itself quite busy by inventing reasons for war (Korea, Vietnam, Afghanistan, Iraq 1, Iraq 2, ISIS, etc.)

  5. wehappyfew says:

    In a similar hypothetical analysis conducted about 1890, it was conclusively proven that the US could never produce more than 1 million barrels per day, mostly because there were not enough coopers and timber in Pennsylvania to make the wooden barrels, and not enough wagons, mules and horses to transport the barrels to railheads for distribution.

    Coal couldn’t be scaled up fast enough, also due to lack of mules to haul coal out of the mines.

    Bottom line: the US would cease economic growth due to lack of energy about 1930 and fall into a permanent Depression. Many would freeze in the dark due to lack of kerosene and coal for lighting and heat.

    • There are a couple of differences with the 1890 US and the 2015 British situations.
      The first is that in the US there was no knowledge of the actual reserves of economically recoverable fossil fuel. We know the availability of wind, hydro, solar and tidal resources.
      The second is that there were huge costs savings to be had from in energy extraction from new processes, refinement of the processes and economies of scale. So within a couple of decades total costs of delivering the the oil to the end user would be customer would be cut in excess of 90%. More recently a similar, though more limited, pattern has been happening in the US with shale gas. Renewables tend to be going the other way. With onshore wind giving way to offshore wind, then tidal. As Roger has shown, the higher the share of renewables in the energy mix, the greater requirements for expensive storage and the lower the capacity of existing fossil fuel plants. There are increasing unit costs of electricity. Only limited cost savings can be had from technological efficiency improvements.
      The third is that in 1890 USA there was open competition on fossil fuel extraction and energy supply – to an extent that we would not desire today. We now have the opposite extreme of highly planned future scenarios. The competitive incentives are very much lacking.

  6. wehappyfew says:


    I think your choices of generating options is skewed too heavily to wind, not enough solar. Triple the solar, cut the wind by the same absolute amount. This changes your storage from weekly cycling to daily cycling.

    Your complaint about solar being useless in cloudy UK… true enough on average, but the days with no wind are less cloudy, and the days with more clouds are – on average – windier. With most of your generating capacity from wind, your mix will always suffer a deficit on no-wind days. More balance, please.

    • Well, it’s not Euan’s choice of generating options, nor is it mine. Mine would include a lot of nuclear and gas and little or nothing in the way of wind or solar.

      Triple the solar, cut the wind by the same absolute amount. This changes your storage from weekly cycling to daily cycling.

      This is a common misconception. Balancing seasonal solar fluctuations poses even more intractable storage problems than balancing stochastic wind generation. See

      • wehappyfew says:

        Maybe I misinterpreted Euan’s OP, where he said this:

        “To construct the scenario I began with the DECC Pathways Calculator, which allows one to juggle 42 different input variables until the desired goal of an 80% reduction in UK emissions by 2050 is achieved.”

        Does that not mean that Euan chose the amount of each type of energy source? And he could “juggle” the PV higher and the wind lower?

        I agree that more nuclear would make the scenario far easier.

        I disagree that seasonal surpluses for solar are an insoluble problem. The UK needs energy in the winter. Solar can provide a good bit of that on low-wind days, even in the winter, by overbuilding PV capacity. This creates an enormous surplus on summer days.

        This is a problem only if you absolutely cannot think of a way to utilize enormous amount of nearly free energy. I predict this “problem” will be solved quite easily. It’s true that the demand-response infrastructure and industries that will take advantage of this free energy source do not exist yet. But build it (the PV), and the demand will grow along with the supply – supply and demand market forces will take care of it.

        • Euan Mearns says:

          WHF – you seem to suffer from comprehension problems. The post was written by Roger Andrews, not me. Roger is using a 2050 Pathway proposed by The Centre for Alternative Technologies to illustrate a point, it’s not his own.

          The UK needs energy in the winter. Solar can provide a good bit of that on low-wind days, even in the winter, by overbuilding PV capacity. This creates an enormous surplus on summer days.

          You now need to provide the detailed numbers to back up this statement. Electricity demand in the UK peaks at 6 pm on a weekday in January or February. Let me see your numbers for solar PV generation 3 pm to 9 pm in the UK, divided into latitude bands, and how this “free energy” is financed.

          If you have come here to learn how the real world works – fine. If all you have to offer is to blabber Green crap then I suggest you don’t waste your’s or my time.

          • Willem Post says:


            A lack of comprehension of reality, because of a lack of knowledge of reality-based facts?

          • wehappyfew says:

            Indeed, my reading comprehension failed. Sorry I mixed up Roger’s ideas with your name.

            But Roger only used a part of the CAT proposed renewable pathway. He left out 2 of their 7 sources of electric generating capacity, so that may have led to some of my confusion as to what scenario Roger was analysing.

            Adding those 2 missing sources of electric generating capacity to the 5 listed here, Roger’s analysis corroborates the CAT plan – Roger’s 55GW deficit on cold windless February nights is met by 10GW of wave energy, and 45 GW of biogas peaking plants.

            It’s encouraging that 2 separate analyses reach exactly the same conclusion.

          • Euan Mearns says:

            Roger, any reason for omitting wave and bio-gas from your analysis?

          • Roger’s 55GW deficit on cold windless February nights is met by 10GW of wave energy, and 45 GW of biogas peaking plants.

            There are no biogas peaking plants in CAT’s scenario. (Biogas is a forlorn hope anyway – see ).

            And if the wind isn’t blowing there won’t be any waves worth speaking of either.

            WHF. If you can come up with a 100% renewables generation scenario that meets hourly February 2013 demand using factored hourly 2013 generation then please tell us about it. If not, please cease and desist.

          • Roger Andrews says:

            Roger, any reason for omitting wave and bio-gas from your analysis?

            If you sum the boxes I checked on the DECC calculator boxes (Figure 2) you will find that wave + tidal flow +tidal stream = 64TWh compared to CAT’s 67TWh. Matching individual totals is impossible. Not enough options.

            I omitted biogas because CAT doesn’t include any (Figure 3).

        • Willem Post says:


          By 2050, UK people can’t wait for summer, with all that free PV energy to really splurge on it, after frequent and often long periods of freezing in the dark during winter, spring and fall.

          Look at the mix of energy in the Stanford study. Some of those sources are not available in the UK and many other places on Earth.

          That means many places on Earth would become much less desirable to live in, i.e., more migration, more boat people, trends which will only accelerate in future years.

  7. ristvan says:

    Roger, this is a terrific analysis. Use ‘the other side’s’ tools and analyses to show you cannot get there from here as claimed. I suspect the foolish Germans will shortly be illustrating your winter dark conclusion for real. French nuclear interconnect will not be able to make up the deficits for both UK and Germany at the same time. Enough to save 10% penetration UK, not enough for 26% Germany, especially if Irsching is taken down as E.ON has threatened. So one gets a sense of how the energy will probably flow. Better to save one of two grids than lose both.

    Thanks also to you for your methane storage post, and to Euan for his FLES post. Both were helpful in simplifying and finishing my recent grid storage piece for Judith Curry. Glad you liked it.

    • Thanks Rud. And your CE post should be required reading for all the policymakers who are leading us down the renewables primrose path without any concept of what lies at the end.

      Interconnector flows in fact already don’t always behave as DECC assumes they will. During winter cold spells electricity tends to flow out of the UK, not in:

      Glad our earlier posts were of help to you.

      • ristvan says:

        The post is free, not copyright, and not part of any planned book. Send about as you see fit. You need a .docx version, just ask. Need .jpg images, already made RTG. Please do fix first the two minor typo corrections in Judith’s version.

  8. Confused Mike says:

    I saw this report today by EDF
    (I have no allegiances to them) in which they appear to have carried out some exhaustive data analysis on historic daily (30 year) PV and Wind generation from climatic conditions across Europe to derive the amount of non intermittent power generation needed if Europe ( I think EU) was to be an integrated power generator/consumer world with 60% RES (40% PV/Wind) and forecast 2030 power demand. It proposes that future PV and wind investments are then made the ‘right’ places – PV in S Europe Wind in N Europe and large scale interconnectors in between.
    Although this is nirvana (to my mind) in terms of integrated investments across a continent they also appear to have assessed how moving from a solar or wind farm to a county/department to a country to a region on variances in power generation from intermittent sources is ‘dampened’ by integration.
    The 30 year data provides some information on the variance winter to summer and year on year for PV and Wind generation (I’m not sure how on and offshore generation is different) which has been an interest to me
    I confess to only looking briefly at it today( i will spend more time when I have it!) and saw the discussion so add it for review by those more expert than myself but this type of data analysis – huge as it must be – is needed to continue the debate on what is needed as RES penetration is undertaken and how big the picture needs to be to understand where national investments are either stranded or undermined by neighbour but independent strategies.

    • Confused Mike: Thanks for the link to the EDF study. I haven’t had time to look at it in detail but here are the take-home messages as I see them:

      While wind and PV production have key roles to play in the European strategy for decarbonisation of electricity production, thermal generation remains necessary in order to ensure security and stability of supply.

      This is the conclusion I and other Energy Matters contributors have reached.

      A contribution of nuclear to this thermal supply would seem necessary in order to achieve the required CO2 reductions.

      This one too.

      There does not appear to be a business case in the next 15 years for wide-scale storage as a means to manage intermittency …

      Right. With enough thermal load-following capacity you don’t need storage.

  9. wehappyfew says:


    You’ve omitted the biogas peaking plants.

    From page 67 of the ZCB: Rethinking the Future – Report, section 3.4.2

    “Biogas and synthetic gas, once stored, can be
    burned in power stations (again, like natural gas
    today) to provide energy when electricity supply
    from renewable sources is insufficient to meet
    demand. Gas power stations burning biogas or
    synthetic gas can be flexible – we can turn them on or
    off quickly. We can use them as ‘back up’ generation
    to meet demand when electricity supplies from
    variable renewables fall short.”

    from page 69:

    “Biogas and carbon neutral synthetic gas are
    burned in gas power stations to supply electricity
    during the 15% of the time when electricity
    demand would otherwise exceed supply. In
    our scenario, we need to produce on average
    27 TWh of biogas or synthetic gas as back up
    every year, to be used as and when required,
    which in turn produces an average of 14 TWh
    of electricity per year. We incorporate a large
    number of (renewable) gas power stations
    (45 GW maximum output, comparable to the
    capacity of all gas power stations we have today),
    but these power stations are inactive most of the
    time, turned on only when electricity demand
    would otherwise exceed supply. Overall, these gas
    power stations only produce 3% of the electricity
    in our scenario.”

    Omitting wave power…

    If I remember correctly, the UK shore enjoys rather large waves in the winter time, even on those rare wind-free days. Waves can travel long distances across the ocean, from storms far out to sea. So the correlation with local wind speed is less than complete. You can verify this on

    Pick the western tip of Cornwall, for example, on this map:,53.59,3000

    Compare the local wave height to the local surface wind speed over time. They are correlated, but significant wave heights are found even at near-zero wind speed.

    There are times when wind-speed is too low to generate power, but we almost never ever see near-zero wave height.

    • A C Osborn says:

      wehappyfew, Wave Power has already been discussed on here and is just another irritating Intermittent energy source that disrupts the base load stations, making them less efficient.
      As for Bio-gas, it needs very large investment in both production and storage and is going to be expensive.

      Sorry but I just cannot understand “CO2 Reduction at any Cost” attitudes.

  10. Alex T says:


    This is an excellent analysis and you’re right that the pathways calculator doesn’t cover this.

    A question: Can you reset the calculations to identify

    1. What amount of storage we would need in February 2050, under the zero HVDC and generous HVDC assumptions? (One scenario is that our neighbours won’t have surplus capacity when the UK doesn’t, but that Norway acts as a reservoir for all. My assumption is the Norway won’t have enough for the UK, Germany, etc).
    2. In 2050, to avoid the freezing, how much gas would we need? In terms of capacity, and actual usage?

    Also, the DECC calculator may be a bit pessimistic.:
    “The CAT scenario contemplates that annual UK electricity generation will double between 2013 and 2050 from 359TWh to 738TWh.” A 369TWh increase.

    30 million cars x 10,000km average distance x 0.15KWh/km (for a 1.5 ton car) = 45TWh for all the cars in Britain. Be generous, and double that for all transport gives 90TWh per year. That averages to 10GW, mostly at night.

    For heating you can make various assumptions. A current house needs 120KWh on a very cold day – assume in 2050, 60KWh, with a COP of 4 = 15KWh of electricity, times by 20 million = 300GWh/day. I’d guess a peak capacity requirement of 20GW. As heat is easy to store over a 1 day period, you could assume this is NOT at peak times (7am – 10am or 4pm – 8pm).

    So, night demand = 40GW current night time demand + 20GW for heating + 20GW for EV charging = 80GW
    Day “peak” demand = 60GW + 10GW heating + 10GW EV charging = 80GW.

    So I think it’s reasonable to assume a cold January (less solar than Feb) needs 80GW, pretty static. Putting that into your figure 5 identified a need for about 60GW of capacity on standby – either Battery, Gas, or the mythical HVDC links.

    Looking at your charts and guessing, it seems we still need 120GWdays of storage, or 2880GWh, or seven times the DECC high scenario. Or 144KWh/household, or about 12 of these Tesla battery packs.

    Of course, biogas can help to an extent. But not enough to close this gap.

    • Thanks Alex T, and apologies for the delay in replying.

      I estimate that ~3,100GWh of storage would be needed to offset the February 2050 power deficits before including imports – about the same as your estimate – and about 1,500GWh after.

      DECC has estimated the cost of power outages (loss of load) at £17,000/MWh. Using this number the total cost of the February 2050 outages works out to £172 billion before imports and £51 billion after.

      • Alex T says:

        Thanks. I think the DECC estimate is high. I’d pay £1.70 to get 0.1KWh for 20 minutes of computing time. Whether I’d pay £50 to avoid an 8 hour black out? Don’t know – I only experienced that in Spain.

        At £17,000/MWh, every home would have a diesel generator.

        Which begs the question – there are two technologies that can overcome the shortages:
        1. PHEVs. Once the price goes above a certain amount, my car, which is plugged in with a full tank of petrol, turns on and feeds the nation. Very inefficient, uses petrol, but could be good for standby.
        2. Domestic scale fuel cells. These can turn gas into electricity at 60% efficiency. They can also be centrally controlled to make up a shortfall – 10 million fuel cells able to produce 6KW of electricity and 4KW of heat.

        If we have to have fossil fuels in 2050, these are the optimum ways to use them.

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