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Matching Supply and Demand In A Low Carbon World

December 19, 2016

By Paul Homewood



There is one very interesting chart I have come across in the working papers for the CCC’s Fifth Carbon Budget:




The CCC notes explain it:

Figure 3.4 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.


In other words, this is what the demand/supply balance could look like under a typical 2030 scenario, with the sort of high deployment of nuclear/wind/solar required to meet carbon targets.


Two things stand out.



1) There are times when low carbon sources cannot supply all of demand.

This will come as little surprise! But what may be revealing is that this is not simply an issue for a few days in winter. Or, for that matter, just a shortfall of a couple of GW or so, that we can fill with diesel engines and DSR.

Instead it would appear that there could be large shortfalls for 30% of the year.

Even the CCC recognise that CCGT will need to supply something like a quarter of our electricity in the Fifth Carbon Budget period of 2028-32.

But nobody seems to have any plan at all of what we are supposed to do in the years after, as decarbonisation targets become progressively tighter.


2) Just as significant though is the other end of the graph.

There are times during the year, maybe as much as half, when supply far exceeds demand.

If the answer to (1) is to build more low carbon generation, this will simply exacerbate the problem.

Of course, there is always going to be spare capacity, particularly in summer months, with any generation set up. But with conventional technology this can be easily planned for, for instance using downtime for planned maintenance.

With a lot of renewable energy in the mix, this is not possible.

But the other big problem with renewables is their variability. Because of this, you need much more capacity to produce a given output.

The CCC, for instance, offer some scenarios below for a 2030 Scenario:




Given the big problems experienced with Hinkley and the unlikelihood of CCS becoming commercially viable anytime soon, the most likely scenario is High Renewables.

Because of the inefficiency of wind and solar generation, the CCC reckon we will need 103GW capacity of low carbon capacity. (This is in addition to back up capacity).

Consequently, when it’s windy in summer, there is going to be an awful amount of excess generation.

Which raises the question, who will pay for this?

  1. Joe Public permalink
    December 19, 2016 1:43 pm

    That chart implies that for ~93% of the year, zero-carbon sources *cannot* meet daily 24-hour demand.

  2. December 19, 2016 1:44 pm

    Help is on the way. West Virginia’s 5 Electors meet in Charleston, the State Capitol, this morning to cast their votes for Donald Trump in the Electoral College. This will happen across the country. Electors are determined by the number of US Senators (2) and Congressmen (based on population and at least one) from each state. This is the genius of our Constitution (proposed by Alexander Hamilton) to keep the large population areas from controlling the whole country.

    • December 19, 2016 2:05 pm

      We just have to hope that Donald kills off the climate change industry in the USA, followed by killing off the ruinables scam, and that the UK has enough sensible politicians to go down the same route. On the downside, we have very few sensible politicians over here.

      • BLACK PEARL permalink
        December 19, 2016 2:54 pm

        What normal ‘sensible’ people ever want to be politicians in the first place!
        Most are agenda driven deluded activists, scammers, or a combination of the both.
        ‘Sensible’ means sticking your neck out like a turkey which most will not do, as it usually invites the attention of an axe.
        There are some but they usually get vilified for their stance.
        Even happened to Churchill in ’39-40
        Lets hope Trump can lead the way out of the mire
        Fingers crossed for 2017

      • Gerry, England permalink
        December 20, 2016 1:57 pm

        Brexit is showing just how stupid the MPs and worryingly the ministers involved in it are as they can’t understand the customs union, the single Market or the common commercial policy and what effect they have. The legacy media are equally stupid as they continue to claim that Turkey, Andorra and San Marino are in the EU customs union that only EU sates can be in. Most MPs are just nodding dogs who have their eyes on a post in government. Doing what we pay them to do and hold the executive to account would see them have no chance of a post. So dross like Nicky Morgan end up being ministers let alone MPs.

  3. Joe Public permalink
    December 19, 2016 2:01 pm

    Paul, Fig 3.4 is being ‘sold’ to the gullible with its headline label:

    Figure 3.4: With higher deployment of nuclear, wind and solar (consistent with 100 gCO2/kWh) combined output could often exceed hourly demand [My bold]

  4. December 19, 2016 2:02 pm

    “Which raises the question, who will pay for this?” I think we all know the answer to that one. At the end of the day, everything is paid by the consumer, whether it is households, industry or commerce. Industry and commerce pass it onto the domestic consumer. Mind you there won’t be much industry and commerce left, and very few taxpayers.

  5. Broadlands permalink
    December 19, 2016 2:29 pm

    The CCS estimates in the chart appear to refer only to the reduction in emissions? If true, then not even one ppm of CO2 will have been removed from the atmosphere, which likely will have continued to rise. The estimated cost of CCS is currently around $130 US per ton. And the current estimate of emissions is 25-30 billion tons, annually. Somebody’s pocket will be picked. This is quixotic…tilting at windmills?

    • December 19, 2016 4:01 pm

      No, the CCS figure is the GW from power stations fitted with CCS

      • Broadlands permalink
        December 19, 2016 4:40 pm

        “… the unlikelihood of CCS becoming commercially viable anytime soon, the most likely scenario is High Renewables.”

        In other words? No reduction in atmospheric CO2 until???

  6. December 19, 2016 3:05 pm

    Confused about how they generate the seemingly random green plot in that chart if it claims to be ‘sorted’. Surely a more relevent plot would be the worst case output of wind and solar at each sorted demand hour (which we know is practically zero) and the ‘best case’ output assuming wind is blowing at an idea, speed all year round. For instance we know that solar output is near zero when demand peaks after sunset on winter evenings – but this doesn’t appear to show up in the green plot as shown. So the chart seems disingenuous at best.

    • December 19, 2016 4:03 pm

      The idea is that the graph is hourly demand sorted from high to low.

      Then, the amount of power from low carbon sources for each of those hours is added

  7. December 19, 2016 3:08 pm

    Solar will be more or less a write-off from about November to February, which is the most likely period for high demand. On the ‘most likely’ scenario that then leaves us hoping the wind blows at times of peak demand, which is a flat-out gamble that will sometimes be lost.

    Call that an energy policy?

    • Joe Public permalink
      December 19, 2016 5:53 pm

      Euan Mearns produced a chart of UK January power demand vs solar contribution.

      Those with keen sight will notice solar bumps along the x-axis; and, produces zilch during each day’s period of peak demand.

      • It doesn't add up... permalink
        December 19, 2016 8:23 pm

        Doesn’t look any better in Jan 2015, even with wind included. Max demand around the 20-22nd with essentially zero renewables.

  8. CheshireRed permalink
    December 19, 2016 3:08 pm

    The stupidity of our CC Act is quite breathtaking. Ed Millitwats top-3 place in the annals of insane politicians is assured for decades to come.

    • Gerry, England permalink
      December 20, 2016 1:59 pm

      I think you should also blame all those who voted it through as well. They are equally guilty.

  9. December 19, 2016 3:41 pm

    Do remember that excess power from solar and wind is effectively free to the network (already paid for) driving wholesale prices down and putting base producers out of business.

    • December 19, 2016 4:05 pm

      That’s right Ron.

      The problem come 2030 is that, on the basis of these figures, solar, wind and nuclear will all be competing with each other, and not fossil fuels.

      If wind and solar start going out of business as a result, life will become interesting!

  10. December 19, 2016 3:48 pm

    “Which raises the question, who will pay for this?”
    That’s not the correct question.
    Ask instead, “How are we going to stop ’em?”

  11. John Peter permalink
    December 19, 2016 4:09 pm

    A dictatorship is when a small elite imposes their will on the population. We are on our way. Less than a thousand individuals are guilty in this country. Westminster politicians and selected government civil servants. (Minus Bradby et. all.). Typically an unsuccessful war or a revolution ends the misery. I predict that at some point the voters will clear the Westminster decks when the costs through taxation and energy bills reach a certain level and the knowledge that the money is taken from the poor and given to the rich sinks in.
    Trump may accelerate this process, but the switch away from the Climate Change Act will happen well before 2030. It will not be pretty and the country may be unrecoverable from the demise in terms of the economy and well paid employees to pay the necessary taxes.
    On a personal note I simply cannot comprehend how CCC can publish such a chart and not demand the cancellation of this monstrous Act. What happened to sanity?

  12. Broadlands permalink
    December 19, 2016 4:37 pm

    Just released by NOAA: The November temperature for the United Kingdom ranked in the coolest third among all years in its series dating back to 1910, at 1.3°C (2.3°F) below the 1981–2010 average. This was also the coolest November for the UK since 2010. The coolest region was Scotland, where the average temperature was 1.6°C (2.9°F) below average.

  13. December 19, 2016 5:05 pm

    Today’s news
    145 parliamentarians(all non governming lame ducks) from 34 countries say in a letter published today in The Times.
    Headed by Ed Miliband, Prescott, Barry Gardiner, Senator Ed Markey, Stephen nepotism Kinnock, Lisa Nandy
    “Climate related Financial Disclosure
    Many assets related to a carbon-intensive economy may now be mis-priced after the ratification last month of the Paris agreement on climate change”
    “Investors require a comprehensive and transparent disclosure of these risks by companies and markets,” they say
    “To that end, we have written to the world’s stock exchanges urging them to adopt climate-related reporting guidance and disclosure for all listed companies.”
    #1 FO you seem to be using propaganda to manipulate down prices. Isn’t that illegal ?
    #2 Paris is a toothless tiger.
    #3 Maybe you didn’t notice but Trump won the election and Climate Numptie governments are on the way out.
    More in CarbonBrief’s daily propaganda here

    OTOH businesses that rely on green gimmick subsidies should warn investors that they are at risk from having them withdrawn.

  14. December 19, 2016 6:44 pm

    That figure is highly misleading, quite possibly intentionally so, if you look closely you can see the green part going to zero at the very left hand edge, but the low resolution makes it appear that wind/solar can supply around 30 GW at that end, which is false by a long way.

    There is a Law of Diminishing Returns for all generators with intermittent fuel sources, quite well known for solar in Australia, where peak demand time is being pushed to ever later times, where solar has less and less effect. The end result will be a peak demand in darkness, where solar has zero effect.

    Wind power has the same problem, but its Academic Cheerleader Squad has raised a smokescreen about it, and National Grid make only vague statements about capacity credit going down as wind power increases. GB wind is already big enough that cold windy days are sorted and can be ignored, the peak demands on non-wind generators are now on cold calm days, ultimately the peak demand will end up on the day of lowest wind power, which at current levels may be an output of (say) 300 MW. To get 30 GW minimum wind power you would need 100 TIMES the current wind capacity, and since wind power can (rarely) vanish almost completely that 30GW of wind would need 30GW of backup.

    Nobody would build a 30 GW conventional generator, because it would need a matching amount of backup, but such common sense rules seem to be waived for the darling wind.

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