The UK’s Fifth Carbon Budget – Without the Green Crap

The Committee on Climate Change, under the chairmanship of Lord Deben, recently released its report entitled Power sector scenarios for the fifth carbon budget. As summarized in this Bloomberg article the report’s basic conclusions are:

  • The U.K. can cut three quarters of the carbon emissions it’s producing from making electricity without driving up bills too much by deploying more clean-energy technologies.
  • Investments that are planned in the power industry in the next five years already are sufficient to reduce the so-called carbon intensity of electricity to 200-250 grams of carbon dioxide per kilowatt-hour, from 450 grams today.
  • Emissions below 100 grams are “an appropriate aim for 2030”.

The CCC report provides three scenarios under which this ~75% reduction in electricity sector emissions can be achieved by 2030 plus four other “alternative” scenarios that either exceed it or fall short. It’s impossible to review these scenarios in detail (the CCC report is 111 pages long and comes accompanied by another 68-page report entitled The Scientific and International Context for the Fifth Carbon Budget) so here I adopt a simplified approach that hopefully sheds some light on what these scenarios actually boil down to.

The key to electricity sector CO2 emissions reductions is of course the generation mix, and Figure 3 of the CCC report shows the 2030 mixes for CCC’s three “base” scenarios – high nuclear, high renewables and high CCS – all of which lower emissions slightly below the 100 gCO2 =/kWh target:

Figure 1: The Climate Change Committee’s three base scenarios for 2030

Because there is little difference between them I’ve picked just the first one – “high nuclear”, although it isn’t what I would call high – to play games with. Figure 2 shows three bar-chart versions of this scenario:

Figure 2: CCC’s “high nuclear” scenario segregated into “load following”, “intermittent renewables” and “baseload” categories

“A” shows the chart as it appears in the CCC report but with the bars labeled so one doesn’t get eyestrain trying to match the colors to generation types.

“B” reshuffles the bars into three generation categories – Load following (gas and hydro), intermittent renewables (solar, tidal and wind) and baseload (biomass, CCS and nuclear).

“C” merges the individual bars into load following, intermittent renewables and baseload categories – hydro remains as a separate category for comparison purposes – and changes the colors for reasons that will also become apparent in the next Figure.

Back in July I published Decarbonizing UK Electricity Generation – Five Options That Will Work. These five options used nuclear to provide constant baseload capacity and gas as load-following capacity to balance increasing amounts of intermittent wind power against UK demand for February 2013, which I used as a proxy for February demand in unspecified future year 20XX. Figure 3 plots Figure 2C alongside my Option 3, which like the CCC scenario also achieves a ~75% reduction in CO2 emissions:

Figure 3: CCC’s 2030 generation mix versus my generation mix in February 20XX

By virtue of diligent analysis or sheer coincidence the CCC and I have independently come up with substantially the same generation mix, and having claimed that my generation mix will work it seems that I must now acknowledge that the CCC’s will too.

But I won’t, because it won’t.

Why not? Because my mix uses only proven generation technologies (I give wind the benefit of the doubt here) while the CCC mix includes a lot of what David Cameron could legitimately have called “green crap”.

What is the green crap? Once again I exclude wind, which although it arguably qualifies is the only viable option if the UK continues to insist on targeting high levels of renewables generation. But CCC’s scenario shows 20% of 2030 total generation (75TWh of 380TWh) coming from a combination of biomass, solar, tidal power and thermal plants equipped with carbon capture and storage. It’s generally accepted that a mix of different generation sources improves energy security, but what are the chances that by 2030 the UK will be generating 30TWh from CCS, which doesn’t yet exist as a commercially-viable technology and the way it’s going probably never will? And of what use is 20TWh of solar generation when almost all of it arrives in daytime in the summer when it’s not needed and none of it at night in the winter when it is? And why should 25TWh of biomass generation, which emits about as much CO2 as coal, be preferred over 25TWh of coal generation, particularly when burning coal consumes long-dead forests rather than living ones? And why should the UK spend £1 billion to generate 500GWh of wildly erratic tide power from Swansea Bay when it can generate maybe five times as much dispatchable power from a couple of new CCGT plants for the same money?

What we are seeing here is green pipe dreams trumping common sense. Replace these pipe dreams with nuclear and maybe a little gas and I could give qualified approval to the CCC’s 2030 generation mix and the UK’s fifth carbon budget. I say “qualified” because it would still look a lot better with a good deal less wind.

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26 Responses to The UK’s Fifth Carbon Budget – Without the Green Crap

  1. Leo Smith says:

    Twas ever thus (green pipe dreams trumping common sense).

    The rot set in with Miliband who at least was merely using energy to further his career and for short term political advantage – but the real disaster as the succession of Lib Dems who actually believed in green crap The krankenhuhner and so on.

    • climanrecon says:

      Count (Ed) Daveycula has been gloating recently about all the expensive windfarm contracts he signed before the election, job losses in steel making don’t seem to have dented his zeal.

  2. oldfossil says:

    It’s interesting to compare Deben’s budget to the five contained in David Mackay’s SEWTHA (page 212 of the book, page 225 of the pdf). Only Mackay’s Plan D bears any resemblance.

    What worries me is that the planning horizon for these wild and wonderful technologies is a decade or more, and just in the seven years since SEWTHA the proposed generation mix has changed substantially. For example Mackay would have spent billions developing pumped geothermal heat. At the same time the new generation of politically acceptable nuclear plants have also turned out to be expensive mistakes. The quest for low carbon energy seems bound to fail.

  3. A C Osborn says:

    Roger, you may be interested in some of the numbers behind the CCC decisions that have ben posted in Bishop Hill.

    Their pricing now and in the future are fantasy land.

    • AC: I didn’t look at prices but I did notice this:

      The Government’s carbon values are designed to be consistent with action required under the Climate Change Act (Box 3). They reach £78/tonne in 2030 and would be enough to push the costs of gas-fired generation up above the level of mature low-carbon options in the 2020s.

      The ultimate goal seems to be all wind and solar and no gas left to balance them with. Another triumph of green planning.

  4. gweberbv says:

    I guess there is a typo regarding the hypothetical solar contribution: 3 TWh is less than what is produced already now. From Figure 1 it looks like the “high nuclear” scenario expects something like 15 to 20 TWh from solar (in 2030). Which is slightly more than half of the production of todays German PV fleet.

    If you are willing to pay 20 billion euros, you can install 20 GW of PV capacity within 3 to 4 years. With this you will get a very predictable energy prodcuer with causes absolutely no trouble to the grid compared to wind (because ramping is relatively slow and prodcution is more or less nearby the consumers). The sun does not shine in the night? Oh shit! Even if it would shine also in the night, you still need a 100% backup because you have this strange things called clouds. No difference to wind here.

    If you have a general problem with intermittent producers then solar is as much a ‘pipe dream’ as is wind.

    • jacobress says:

      Solar has a capacity factor of 10% – it produces electricity 10% of the time ( in Britain) – a few hours per day, only on sunny days. Wind – about 25%-28%.

      “Load following” gas uses probably about twice as much gas (twice as much emissions) as steady 24/7 gas, per kwh produced. So, solar + load following gas (which has to be OCGT) probably produces no less emissions that 24/7 gas (CCGT). So, no matter how much solar you install, it produces little emissions reduction.

      I wonder if the CCC report considered the enhanced emissions caused by using gas in load following mode.

      • gweberbv says:


        I do not buy that solar induces so much ramping that the efficiency of the load following plants is cut by half. If you have a look at the solar peak, you might recognize that for roughly 15 hours of the day there is none. So, no ramping needed. Wind requires much more ramping and partial load operation.

        The capacity factor is low, but what is the general problem with that? Solar can still provide something like 5 to 10% of your yearly electricity production without causing severe problems.

          • ducdorleans says:

            gweberbv, ??? ….

            isn’t this about diesel engines preserving efficiency over the required load curve ?

            the Siemens and GE gas turbines go from 38% efficiency @ 100% load to 26% @ 40% l… that is quite a loss !

            so …
            1. you want us to turn to diesel to generate electricity ? just recently here in Belgium, diesel – for cars, but that’s the same thing that is used in those engines driving generators – has just been named so unhealthy for all us that a new tax was in order

            2. as to the CO2 output of gas turbines being used for load following, K. Le Pair and F. Udo have done some real world calculations … see e.g.

        • Jacob says:

          The profile of solar production is pretty clear: on a sunny day solar electricity is available, roughly, between 10 a.m. and 4 or 5 p.m.
          Supposing we have a steady baseload supply – demand picks up (from the nightly low) at about 7 a.m, so we need to ramp up load following supply at this time. Then the sun kicks in at 10.a.m. and the load following has to be ramped down. Then there is peak demand from 4 p.m. to, say, 11 p.m. – when the sun is not available. So the load follower needs to ramp up again.
          The combination of demand curve and sun availability creates the need to cycle – ramp up and down – the load following plants – twice daily (and more on cloudy days).
          This cycling has consequences – in enhanced tear and wear of equipment, in costs, but also in efficiency loss – i.e. more emissions.

      • PhilH says:

        Solar PV produces power whenever there’s light, not just when there’s direct sunshine, ie 50% of the hours of the year. Its capacity factor of ~10% (in the UK) means that its average output (averaged over the year) is ~10% of its maximum output.

        One of its pros is that its output increases through the morning, helping to meet the rising demand through the morning, so reducing the need for load-following generation, rather than increasing it. In many places, though not so much in the UK, demand falls through the afternoon, and PV’s output falling through the afternoon helps reduce the need for load-following generation then, too.

        Despite the large increase in RE in recent years, National Grid seems to be making ever less use of OCGT (, and I’m not aware of any proposals to build any new OCGT plant in the UK.

        • Euan Mearns says:

          Figure 1 According to The Renewable Energy Foundation (REF), the UK had about 2700 MW installed PV capacity in January 2014. And according to National Grid, this produced 54 MWh of electricity, equivalent to 0.19% of total UK demand. The small, barely visible, blips along the x-axis is the solar PV output. The load factor was 2.7%. Click all charts for a larger and readable version.

          Figure 6 January and July 2014 compared. The January output has been grossed up by a factor 0f 1.45 to reflect the growth in installed capacity between January and July. The summer peaks are taller, more regular and broader. The January and July peaks are also offset by 1 hour, January operating on Greenwich Mean Time (GMT) and July operating on British Summer Time (BST). Peak winter demand is always around 6 pm. At that time in January, UK solar PV production is always zero since The Sun has already set. In mid-Summer, PV output is less than half the midday peak come 6 pm.

          UK Solar PV Vital Statistics

          There’s a lot of hope and half truths down here, which is unnecessary since we have ample facts to demonstrate that solar does nothing for us in winter and never will do.

          • Günter Weber says:


            probably this is why there is still 50% of demand covered by gas and nuclear in these scenarios. If there were no times in the year, when solar and wind ‘do nothing for us and never will do’ there would be no need at all for anything else than solar and wind. But of course there is the need for backup.

            Nevertheless, you can be damn sure that there are times when solar would be able to cover something like 50% of demand without any severe problem. You just need to build a few more tens GW of PV capacity. This can be done within a few years. Contrast this to CCS-equipped power plants, which are really a pipe dream. (Or – I can’t resist – ‘cheap’ nuclear power plants.)

          • Euan Mearns says:

            Gunter, we agree on CCS 🙂 And a clever German pun 🙂 Nuclear is low cost made expensive energy.

          • Jacob says:

            “There are times when solar would be able to cover something like 50% of demand without any severe problem. ”
            Yes, maybe a few hours, in a few days per year….

            We need electricity 365/24/7 not “some times”.

            And, once you have plants that produce electricity at ALL times – what use are those solar panels that produce power “some times”? The solar power is, necessarily, just an appendage to a system that is capable of supplying all needs without any sun.

            Sure, you can achieve “some” reduction in emissions by using solar power, but not “much”, because of the very limited time frame of solar production.

          • gweberbv says:


            in the effort to replace as much conventional electricity production by ‘green crap’, solar can give you a contribution on the order of 10% of total demand (in Central Europe). This is not negligible.

            And – very important – you won’t get this particular 10% with wind so easy. To provide you at least with some anecdotical evidence, please have a close look the wind production during the solar peak for the last days in Germany:
            There is a slight tendency for solar to fill valleys of wind production (of course it is just a tendency).

            Moreover, PV is likely to have the lowest running costs of all energy production technologies. This fact will start paying off once the subsidized feed-in tariffs expire. As long as you exchange the AC-DC converter, a good portion of PV plants will run for decades without significant maintainance costs.

          • Jacob says:

            Yes, solar can, probably, give you 10% of supply, and wind, maybe another 10-15%.
            Where do you get the rest of the needed 80-100% carbon free electricity – needed to save the planet?

            Wind and solar won’t save us from frying, so they are useless.

    • Guenther: You’re right, the number is wrong. Solar generation should be ~20TWh, not 3TWh (and CCS generation should be ~30TWh and biomass generation ~25TWh). I’ve modified the text accordingly. Thanks for picking up on this.

  5. Bernard Durand says:

    Is it reasonable to rely so much on gas for load following? Where the gas used in the UK will come from in 2030? Not from North Sea, it will be empty at that time, probably not from Russia, which will feed China in priority? Note also that ASPO predict world peak gas in 2030!

    • Roger Andrews says:

      If you don’t rely on gas then what do you rely on?

    • Euan Mearns says:

      Qatar, Iran, Tanzania, Nigeria, Egypt, USA, Canada, Russia, Norway, Trinidad. And we have a couple of big new gas fields about to come on. But there is a debate to be had on longer term reliance on gas and the role played by RE in extending nat gas supplies. This is the mantra preached for many years by Jerome. Even with nuclear we need load following generation. I suspect that ideology has killed coal stone dead in the UK for now. It will only ever return if the wheels come off completely and we revert to early 20th century standards.

    • gweberbv says:


      if you have no gas for electricity production, you have a problem. But not so much with missing electricity. The main problem will be that you also have no gas for heating. And heating consumes much more gas than electricity production by gas plants.

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