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How Much Power Will Be Wasted In A Low Carbon World?

October 20, 2019

By Paul Homewood


I looked at the National Grid’s latest “Future Energy Scenarios” plan (FES) a few weeks ago. As you may recall, the plan was based around an alarming shortage of  the dispatchable capacity needed to meet projected demand in 2050.

Today though I want to look a separate aspect.

First let’s consider projected capacity and generation. As usual, I will assume the Two Degree (TD) scenario, which is the core one designed for hitting the original Climate Change Act target of a cut in emissions of 80% from 1990 levels. (The government’s switch to a net zero target was too late for the FES to incorporate):



And if we put the actual numbers on the main items:

Capacity Generation Utilisation

GW Twh %
CCS 12.1 11.9 11
Nuclear 16.6 92.4 64
Thermal 13.4 5.5 5
Solar 42.0 39.6 11
Wind 78.9 268.0 39
Other Ren 13.1 21.0 18


  We can see that capacity utilisation is extremely low on thermal and even CCS, only kicking in when urgently needed. Similarly, other renewables are regarded as low priority.

On the other hand, wind and solar look to be supplying all of the power that they are able to generate. This immediately sounds suspect, given that there will be many occasions when they are producing far more power than the system can possibly take.

Significantly, we also see that nuclear is only running at 64%, a level at which it is totally unviable economically. For instance, the costings for Hinkley Point will, I would guess, assume running at around 95% capacity. EDF’s contract for Hinkley stipulates that they are compensated if its output is curtailed by the government or grid. Therefore, if the market is rigged in favour of wind power, for instance, the government may have to compensate EDF. It is certainly inconceivable that other operators would not insist on the same protection.

It would appear that the FES has deliberately cut its projections for nuclear, in order to make wind and solar look more viable.

Either way, of course, what matters is that the inclusion of so much wind and solar capacity will inevitably create a huge surplus at times, when electricity is effectively just thrown away. The alternative would be to build much less renewable capacity, which in turn would lead to large shortages at other times of year.

To elaborate, the FES is projecting total supply of 457 TWh in 2050, which represents an increase of 37% above today’s figure of 333 TWh.

Last year, supply in the summer half year (Apr to Sep) amounted to 153 TWh, an average of 35 GW. so if we add 37% to that we get 48 GW.

Let’s now make the reasonable assumption that nuclear generation is prioritised, ie that all its output will be used. This is likely to be the case, as nuclear provides an essential baseload and cannot be switched on and off all the time. So that’s 16.6 GW.

Let’s also assume that all solar output is also used. In the summer half year, solar runs at an average of 17% utilisation. With a total capacity of 42 GW, this would yield 7 GW. Note that this assumes hour to hour and day to day variations can be smoothed out by storage.

That gives a base of 23.6 GW, from nuclear and solar. With average summer demand of 48 GW, that would only leave 24.4 GW to be supplied by wind power, and other sources.

About a third of wind capacity is assumed by the FES to be onshore, so a reasonably weighted average loading is 39% (based on 28% and 45% for onshore and offshore respectively). Therefore with a total wind capacity of 78.9 GW, the average would be 30.8 GW.

In others during the six summer months, even if average wind output was maintained 24/7 (or storage was used), 6.4 GW would be thrown away, totalling 28 TWh.

Inevitably however the total wasted would be several times greater, as output is not even. On some days, not enough power would be generated, and on other much too much.

We can of course ignore storage. The FES sets it at 22 GW, yielding little more than 22 GWh if current batteries are anything to go by. That capacity would be barely cover the intra daily fluctuations in solar power. At average capacity of 30.8 GW, daily wind output would amount to 739 GWh.

The other possibility is exporting the surplus, but who would want it? When it’s windy here, it is likely also to be in much of northern Europe. Even if we could sell, it would be at a knockdown price.

The FES does recognise this problem, but seems to underestimate the size of it:



The CCC’s Fifth Carbon Budget did attempt to model the potential surplus, though only on 2030 scenarios.

As we can see, about half of the year sees surpluses, even at a relatively low capacity. (Eyeballing, wind, solar and nuclear capacity looks around 35 GW, compared to 137 GW in FES).


Figure shows hourly demand data in hypothetical 2030 scenario reaching 100 gCO2/kWh sorted high to low against nuclear, wind and solar PV output in that hour.

Remember as well that I have only looked at summer. Even at times of higher demand in winter, there will be many occasions when there is surplus wind power.

My guess is that we could be talking of 100 TWH plus wasted each year. At an average price of say £100/MWh, this would cost £10bn a year.

Which begs the question – who will pay for it? Either way, as the proportion of low carbon electricity increases, the economics of intermittent wind and solar radically change.


The table has been corrected due to typos

  1. October 20, 2019 7:47 pm

    Reblogged this on Climate-

  2. George Shaw permalink
    October 20, 2019 7:58 pm

    If the energy is effectively free, does it matter if it’s wasted?

    • Chilli permalink
      October 20, 2019 8:14 pm

      It’s not free since politicians have signed us up to pay for every KWH wind generates – even if it cannot be used and must be given away or curtailed / shut-off.

      • George Shaw permalink
        October 21, 2019 6:11 pm

        we’ve also been committed to buy Hinkley’s output, at a huge premium over rival costs.

      • Stuart Brown permalink
        October 21, 2019 6:44 pm

        George, there have been posts on here comparing the CfDs before, but a couple of examples to bring us up to date:

        Drax 3rd Conversion Unit (Unit 1) Current strike price 113.65£/MWh
        Beatrice Phase 1 (Wind Farm) Current strike price 158.73£/MWh
        Dudgeon Phase 1 Current strike price 170.03£/MWh

        and …
        Hinkley Point C Current strike price 101.99£/MWh

        Now, over £100 is pretty high, but we are currently paying more than that to Drax and some wind farms apparently. No vast premium there.

      • Stuart Brown permalink
        October 21, 2019 6:47 pm

        sorry – meant to add link for source:

  3. Athelstan. permalink
    October 20, 2019 8:02 pm

    “The other possibility is exporting the surplus, but who would want it? When it’s windy here, it is likely also to be in much of northern Europe. Even if we could sell, it would be at a knockdown price.” /quote.

    I’ve read that and about the ‘german miracle’ and energiewende, large German industrial units don’t want juice generated from renewable sources, nor do the Poles, Swiss, and Czechs – either.

    renewable energy generated from wind, is just – a very, very bad joke.

    how cheap will it be, there are no real estimates, we do predict that, depopulation and early deaths by the millions, will keep on reducing the demand.

    • Broadlands permalink
      October 20, 2019 8:26 pm

      There won’t be a low carbon world until the stakeholders are taxed to the point that nobody other than the wealthy socialist leaders can afford to buy gasolines or diesel fuels. Most of the refineries, even those producing biofuels, will be out of business. A very, very bad joke? An economic Cat 5 hurricane for transportation created by the “urgent” demand to lower emissions to Net-zero. Absurd, even in a theoretical world.

    • Graeme No.3 permalink
      October 20, 2019 11:43 pm

      The Poles and Czechs have installed phase shifting transformers at their junctions with the German grid, to prevent sudden surges upsetting their reliable supply (coal in Poland, nuclear in Czechia).
      The Swiss aren’t connected to Germany except through the French grid. Being Swiss I think they would take surplus electricity at a very low (or even below zero) price and store it in their pumped hydro scheme, much as the Norwegians and Swedes do (although they don’t bother with storage, just shut down their hydro when the supply is so cheap).

  4. Joe Public permalink
    October 20, 2019 8:19 pm

    “To elaborate, the FES is projecting total supply of 457 TWh in 2050, which represents an increase of 37% above today’s figure of 333 TWh.”

    For perspective, in 2018 GB gas demand was 877TWh vs 333TWh for electricity demand; & only ~285TWh of the gas demand was by gas-fired power stations. (i.e. 592TWh of gas used for heating/process-use/feedstock etc)

  5. October 20, 2019 8:23 pm

    The late Professor Sir David MacKay showed 10 years ago (I cannot believe it is 10 years since I bought his book) how infeasible all this intermittent and unreliable renewable energy is and how an excess or a shortage couldn’t be dealt with by storage. Why does his excellent work continue to be ignored? Answer – follow the money and realise the gullibility and stupidity of our politicians.

    How many MPs in this country understand this? Certainly no more than can be counted on the fingers of one hand.

    • Steve permalink
      October 21, 2019 5:19 am

      Prof Mackay also focused on the worst case scenario of a long freezing midwinter lull with no wind and solar. The capacity for backup shown above is inadequate. The CCC seems to gloss over this by suggesting that stored hydrogen and largely redundant gas, both with carbon capture, will keep the heat pumps, factories, offices and transport going. How much energy will it take to convert and store all that hydrogen and bury the CO2? The hydrocarbon and wind lobbyists must be very pleased that Gummer’s goons have ignored MacKay and reduced nuclear rather than building much more.

  6. Immune to propganda permalink
    October 20, 2019 8:27 pm

    Wind power only generates 25% of the time, which of course means it’s practically useless. A free energy market wouldn’t bother with turbines, here lies the problem; we don’t have a free energy market, we have gullible idiots called politicians draining our pockets to the tune of £500 per annum on utilitiy bills by 2023.

  7. John Peter permalink
    October 20, 2019 9:02 pm

    One of the few times it looks as if being close to 80 years old is a distinct advantage. I feel for the poor people who have to live in this mad country as these scenarios unfold. Look at emigrating to India.
    Alternatively, we may see Hong Kong circumstances, until all politicians are replaced by thinking individuals. A few power outages or the point where the middle class may have to decide between heating and food might create unpleasant circumstances for politicians and the rent seekers.

    • Pancho Plail permalink
      October 20, 2019 9:40 pm

      It is sad, isn’t it, that the children who accuse old people of stealing their future look like being the ones that will perpetuate this madness and consequently seal their own fate.

      • Bertie permalink
        October 21, 2019 9:08 am

        I prefer ‘ironic’.

  8. john cooknell permalink
    October 20, 2019 10:19 pm

    A long time ago in 1967 and 1973, when Israel went to war with the Arabs and the Oil supply to us was cut off, instead of focusing our efforts on coal, research was directed by HM Gov to find ways of using wind, solar and wave energy.

    I played a small part in that effort as a undergraduate engineer. To be honest the problems now being faced in getting things to work economically were all found out at that time. The technical problems were just the same, we thought some problems were “just too f***ing hard” to ever work reliably.

    We battled on for quite a few years and started to solve the technical problems, but you can always rely on Whitehall to cancel the project just as it starts having success. One of my old engineering colleagues told me that this was the political strategy all along, to make it look as though something’s being done, but in reality nobody cared.

    • The Man at the Back permalink
      October 20, 2019 10:38 pm

      John, am I right in thinking that you should have started your excellent comment with

      “A long time ago in 1967 and 1973, when the Arabs went to war with Israel” ?? – Or is that not PC these days.

  9. October 20, 2019 11:02 pm

    Hey Paul, You’re certainly not asking people to think are you? This low/no carbon future will just because, uh, because, uh…OFI!

  10. Graeme No.3 permalink
    October 20, 2019 11:55 pm

    I think you have been rather generous in your estimates of the performance of renewables. I noticed that the on-shore turbines can vary between 23 and 28% CF annually.
    Also 17% generation from PV solar at 17% seems generous too. Here in Adelaide, South Australia the CF for solar is measured at 17%. South Australia is the driest State on the driest (inhabited) Continent, and Adelaide is a lot closer to the Equator than London (it’s the equivalent of somewhere in Morocco). And we have experience in what happens when politicians design your electricity supply.

  11. John Peter permalink
    October 21, 2019 9:06 am

    Re Graeme No. 3 above, the whole thing will collapse if we get at winter like 1995/6 when we had no wind for weeks and minus 5 day/minus 15 night days on end. Just imagine the riots in a dark country. At least the marches will keep people warm.

  12. europeanonion permalink
    October 21, 2019 9:46 am

    I would imagine that to those focused on the ecological aspect of the case what is written here (even if they stepped aside from their obsession to read it) would be irrelevan, stuff yet un-imagined will save us. The crunch moment is in some future time and, like growing old, seems as though it might never happen (until it does). The only factor that actually matters is brought about by advertising/selling of politics in an expression of ‘your’ concerns, whatever they are, in the ever changing world of the milieu. Fashion trumps facts. We may be able to say ‘I told you so’ but until our politicians are more accessible and more accountable (yes, the adoption of Brexit) then nothing is going to touch that which seems to be a form of mania, (a nation has different concerns from that of a union, becomes and average of intentions rather than a singular necessity). Mass hysteria is being stoked by the bien pensant; it sounds good at dinner parties. We are fast approaching a time when coercion alone will be the only tool to set matters straight. Pakistan has a will to industrialise and builds its power stations. We, unfortunately, as a mature democracy, witness the disconnect between that sort of nationalism and democracy. The state cannot impose itself because that would be undemocratic and in this way sense becomes subservient to romance.

  13. A C Osborn permalink
    October 21, 2019 10:44 am

    Paul, I have a serious question.
    This is an analysis based on Nationals Grid’s FES for 2050, that is 32 years away.
    How much of our current On Shore Wind & Solar will still be operable after another 32 years?
    Have they even thought about it?

    • The Man at the Back permalink
      October 21, 2019 11:22 am

      Of course not A C – we will all be dead by then! Well most of us anyway.

      The generation who think they have had their childhood and their future stolen will have to clean up their own mess.

      I would willingly live my life again, but everyday now I am thankful that I am not 20 today.

    • George Shaw permalink
      October 21, 2019 6:07 pm

      Solar panels don’t suddenly stop working after the 25 years typically guaranteed, they simply degrade over time, so most are still good for 80 or 90% performance.
      There’s an emerging business for recycling them, so far it’s relatively small simply because most large solar deployments are fairly young.
      Likewises, the batteries used to buffer the supply slowly degrade over time, many are actually batteries removed from electric vehicles. Consider that a 12kWh battery will power a house for an entire day, and most EVs come with 40 to 60kWh packs, so even if half degraded one EV pack can become batteries for two houses.
      Wind turbines are supposedly rated for 25 years too.

      • Immune to propganda permalink
        October 21, 2019 7:20 pm

        Solar panels are crap and you shouldn’t be pretending they aren’t.

      • George Shaw permalink
        October 22, 2019 10:42 am

        I strongly disagree that PV is crap. You can buy a 300W panel in the UK for about £140 inc vat. The pro-rata share of the cost of a 3kW inverter is £40 inc vat, for a total of £180.
        The grid cost is about 15p/kWh. So you need 1200 hours of peak sunshine to break even. The average amount of daily sunlight you’d need over two years to meet that would be less than an hour and a quarter, which is easily achievable in most parts of the UK, and trivial in, say, Arizona.

        Not everybody who installed PV after the UK government ended FIT subsidies, did so because of some sort of religious mass self-hypnosis green delusion, but would have done so because the economics made sense. To dismiss them as “green nutters” as so many here do, just causes more tribal/partisan behaviour.

      • It doesn't add up... permalink
        October 22, 2019 12:08 pm

        Redo your arithmetic. There are 8760 hours per year. So 1200 hours is 13.7% of that. Some way above typical solar capacity factors in the UK, especially away from the SW (where most solar farms are). If it were such a good deal then solar installations would be continuing apace even with subsidies have been substantially reduced. They aren’t:

      • George Shaw permalink
        October 22, 2019 1:35 pm

        there may be 8760 hours in a year, but you need sunlight to make electricity. thus I was approaching it on a worst case insolation scenario to make the point that PV can pay for itself by reducing the bill for buying energy from the grid.
        here’s a useful map:

        the problem is that exporting to the grid only pays back 5p/kWh or so, thus using all the energy yourself is key.

  14. Ray Sanders permalink
    October 21, 2019 12:52 pm

    Well for those who like a good laugh, try reading Jillian Ambroses’ latest load of drivel in today’s Graun.
    I have emailed the Graun to point out the numerous amounts of pure drivel in this article (MW per hour!) and got an evasive reply from Damian Carrington. I have escalated my initial query into a complaint. Will let anyone interested know of their response.

    • Malcolm Skipper permalink
      October 21, 2019 5:29 pm

      Ray Sanders, well done – the article is drivel. I wish you well in eliciting a response.

      The Guardian article includes this paragraph:


      Presumably JA and the Guardian editors don’t know that grandfather clocks work by raising ‘weights’ and allowing them to fall; hardly new nor surprising.



      That sums it up: forget the first law of thermodynamics that energy can neither be created not destroyed – that’s an old-fashioned way people understood the world.

      Is this the level that the Guardian references for understanding of ‘the science’?

      • Ray Sanders permalink
        October 21, 2019 8:08 pm

        Damian Carrington’s reply (the “Environment Editor”) read as follows
        “thanks – I don’t manage Jillian
        concerns about accuracy are best addressed to the Readers’ Editor
        In other words ” yes I know her article was crap but there is nowt I can be arsed to do about it” !!!!! And he seems to have a problem with capital letters
        I will let you know if I get a response from the “Readers’ Editor” that Mr Carrington could not be arsed to forward my email to.

      • Ray Sanders permalink
        October 21, 2019 8:52 pm

        Just noticed a complete re write of whole sections of the article including “MW per hour” being totally erased………what a surprise.

    • George Shaw permalink
      October 21, 2019 5:48 pm

      I agree that “gravitricity” and similar schemes relying on potential energy are bunkum. mostly because the energy density is pretty poor. A 1kg mass raised by 1m only stores 10 joules (approx). A useful unit of energy is 1 kWh, which is 3.6MJ.

      So you need 3.6 metric tons raised by 100 m to store a single kWh, if my ready reckoning is correct, which is hardly scalable! This only really works for something like hydro where you can have hundreds of thousands of tons of water raised by hundred meters or so.

    • It doesn't add up... permalink
      October 21, 2019 10:48 pm

      Here is a proper evaluation of this technology:

      Not completely useless, but the quantities of energy storage are too limited for anything other than grid stabilisation duty in competition with batteries and inertia. There are a number of cost uncertainties.

  15. Dan permalink
    October 21, 2019 3:36 pm

    Would a possibility be, in the case of off-shore wind farms, to use the excess to produce hydrogen for use in Hydrogen Fuel Cells?

    • October 21, 2019 4:34 pm

      Electrolysis is an extremely expensive and small scale way of producing hydrogen, which is itself more expensive than natural gas. It is feasible, but simply adds even more costs.

      It is probably cheaper just to throw the surplus energy away

    • George Shaw permalink
      October 21, 2019 6:01 pm

      If I was cynical (deity forbid!!) then I would say that switching to a hydrogen economy is probably something Big Oil would prefer.. because:
      * producing H2 isn’t something you effectively do on a small scale like a domestic property
      * oil companies would still control the energy supply chain and people would still have to go to their filling stations to refuel.

      also, Governments would like it too because they can then tax h2 fuel.

  16. Jret permalink
    October 22, 2019 8:23 am

    The simple fact that the output of a wind turbine varies with the cube of wind speed means that as you add more turbines to the grid, the huge cost of paying them not to generate when the wind speed increases will rise rapidly. It also is the reason they make such poor sources of power is an intermittent wind environment.

  17. It doesn't add up... permalink
    October 22, 2019 10:38 am

    Paul – I think you miscopied data on TWh of generation in the table – it doesn’t stack with the capacities and utilisations.

    There are a lot of funny projections in that workbook. Also of interest is the methodology:

    Click to access fes-modelling-methods-2019.pdf

    Apparently they assumed the weather would be permanently like 2012. Not clear how they treated demand response (I suspect they called on as much as they needed regardless, but did they add it back to later demand as well?) or interconnector availability.

    • It doesn't add up... permalink
      October 22, 2019 11:58 am

      2012’s 39% for offshore wind is an average year. I wonder how they would do in a 2010 (32%) or a 1986 (44%)?

    • October 22, 2019 12:34 pm

      It looks like the TWh for wind, solar and others is the % utilisation!!

      S/Be 268 TWh – wind
      39.6 TWh – solar
      21.0 TWh other ren

      The other lines seem OK

      I’ll correct, thanks

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