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Massive Renewable Capacity Will Unbalance The Grid

May 31, 2015

By Paul Homewood 




I outlined a few days ago the energy projections that the UK govt was working towards up to 2030 and beyond. 

The central scenario assumed a massive increase in renewable and nuclear capacity, which, on current prices, would could potentially be adding at least £15bn a year to energy bills by 2030.

As Philip Bratby rightly pointed out, I did not allow for the cost of constraint payments. Currently, wind farms are paid to switch off their turbines when it is windy and they are producing more power than the Grid can cope with.

Last year, £53 million was paid out, a relatively small sum in the overall view of things as wind capacity is still small. This situation, however, is due to change drastically in coming years.

Let’s just remind ourselves of the projected capacity mix for 2030.  



Capacity by fuel: all power producers    

2014 2030
Coal 21 0
Coal and natural gas CCS 0 5
Oil 2 0
Natural gas 38 39
Nuclear 9 14
Other Thermal 1 1
Renewables 25 62
Interconnectors 5 10
Storage 3 3
Total capacity 103 133


Outside of the winter months, total UK demand typically hovers around 30GW, which will leave us with a huge problem come 2030. 




It is reasonable to assume that nuclear will provide the baseload. Quite apart from the technical and operational problems of switching nuclear on and off, it will not be economic to build nuclear power stations if they are only to operate intermittently. 

Indeed the contract for Hinkley Point contains this provision:

Arrangements whereby Hinkley Point C would be protected from being curtailed without appropriate compensation. If export of power from Hinkley Point C is curtailed by the operator of the national transmission system and NNBG receives less compensation than is available under current market arrangements it will be able to claim compensation for this difference in respect of any power it has sold on the Season Ahead market.

Put simply, if the Govt or National Grid give preferential treatment to power from wind farms, Hinkley would be entitled to compensation.


So if nuclear is supplying 14GW out of a total demand of 30GW, only 16GW would be needed from renewables. (Assuming gas and CCS are for standby). It may be that the interconnector could export another 10GW of renewables, although when the wind is blowing it is unlikely France or the other countries at the end of the cable will be needing our surplus electricity.

We could therefore be faced with as much as 38GW of surplus power from renewables, even assuming 10GW of export, when they are working at 100% of capacity. Most of the time, of course, wind farms and the other renewables will be running at much less than full capacity. Nevertheless, there will inevitably be an awful lot of surplus power kicking around the system.

Whether the current system of constraint payments continues, and what it will end up costing, I have no idea. But one way or another, there huge problems lie ahead.

  1. Joe Public permalink
    May 31, 2015 1:40 pm

    As Philip Bratby rightly pointed out, I did not allow for the cost of constraint payments. Currently, wind farms are paid to switch off their turbines when it is windy and they are producing more power than the Grid can cope with.

    Let’s not forget that when the windmills are constrained-off, they’re not creating ROCs either.

    As with any other commodity, when there are fewer available, their price rises.

    So on extra-windy days, they win twice-over.

  2. May 31, 2015 1:52 pm

    Good post.

    The really critical issue will arrive before 2020 at planned, expected rates of wind growth. Balancing wind power requires CCGTs to start, ramp and stop times in a manner far outside their design spec.

    In turn, these will need to much higher specific fuel consumption (and CO2 emissions) and greatly increased operational damage (and therefore cost) than has been acknowledged by economist-dominated, engineering weak, DECC.

    So yes, this is also a great business opportunity for some!

  3. chazzone permalink
    May 31, 2015 3:21 pm

    Paying wind farms to switch off in windy conditions is absurd, and just another example of the scam aspect of this boondoggle.
    Since the problem is “storage” of the energy produced, then they should be producing hydrogen when the supply exceeds demand load.

  4. auralay permalink
    May 31, 2015 4:03 pm

    Via Judith Curry,, this site argues that there is an upper limit to the amount of any variable energy.
    “We think there are clear reasons to expect the share of VRE in system-wide electricity mixes to be constrained. Indeed, we offer a rough rule of thumb that is supported by a growing body of power systems research: it is increasingly difficult for the market share of variable renewable energy sources at the system-wide level to exceed the capacity factor of the energy source.”

  5. tom0mason permalink
    June 1, 2015 2:00 am

    Oh Paul really!
    Stop frightening the sheeple!
    DECC knows best…
    There is no need to worry as in a few years most of the UK households will have clever ‘smart’ metering that will limit consumer demand to the required system level.

    Surely you understand that by 2030 the utopian dream of restricting individuals ability to just demand electricity, by mere whim or fancy, will be removed as the ‘smart’ automated systems regulates user demand to the correct requirement, and to a price all producers can live with.

    Remember that with ideas from the Middle Ages being recycled with wind power —

    The future is Green
    — The technology is expensively medieval.

  6. RockySpears permalink
    June 1, 2015 7:40 am

    You can safely remove all “subsidies” for renewables. The BBC today report:

    “Johan Rockstrom, of the Stockholm Resilience Centre in Sweden, told me in April that the world had moved on since Copenhagen, and was now better informed.

    “We have so much more evidence compared to 2009 on the opportunities to succeed in the transformation towards a low carbon world economy, and secondly we have much more science to support the necessity of urgent action,” he said.

    “Solar and wind technology in particular is now at grid parity – or is competitive compared to fossil fuels.” ”

    So everything is fine and cheap.

    The same story also re-enforces the 2 degree break point (which is now most likely broken already).

    And this time the science is even more settled!

    Source: (if that is what you call it)

  7. June 1, 2015 9:08 am

    As I said before, I don’t think that we are ready for offshore or onshore energy, that we’ve analysed all the risks and all the benefits that come from this kind of energy. For example, here are the plans for offshore wind energy in the North Sea: Those offshore facilities influence tides and currents and are stirring the water, making it warmer. In this way, they seem to influence even the climate, which is not ok.

  8. June 1, 2015 10:35 am

    The document Paul found is a real eye opener. The policy is first to use gas to fill the gap left by coal and to load follow wind. Then to reduce gas generation as nuclear generation increases (from 2024). So nuclear base load, intermittent wind, continuing gas to fill the gaps.

    The problem is that the capacity factor for CCGT has been declining monotonically from about 60% in 2009 to about 23% in 2014. So how can it be economic to run a CCGT if you can’t sell electricity? Capacity payments – so we have to subsidise gas and renewables.

    Is that crazy? What you think about that depends on what you think about Climate Change, and for a politician what his/her voters think about it.

    The biggest problem is building Hinkley ‘C’. Areva have not managed to build one yet. And the cost is becoming ridiculous. I doubt that it will happen.

  9. Crustacean permalink
    June 1, 2015 4:34 pm

    One must admit there is a certain, ironic appropriateness about paying wind farms to do what they do best, i.e., not generate electricity.

    • David A permalink
      June 3, 2015 5:01 am

      So wind receives payment when they do not operate, and when they do operate conventional must throttle back, thus reduce efficiency, and be ever ready to throttle up if needed, thus wind, 100 percent of the time increases the cost of energy, not even considering true subsides.

      • AndyG55 permalink
        June 3, 2015 6:19 am

        All power suppliers should have a “contract to supply” whereby they say how much energy they will supply, at what time of the day and at what cost. Bidding starts at say 3am each day, closes at 4am for the day.

        Distributors can then get the best deal for their customers from which ever source they want. No priorities or mandates.

        Over-production is not the distributors problem to solve.
        If a supplier does not meet , say, 90% of their contract, they should be fined or loose the contract for the next day.

        The renewable wonks say wind and solar are on parity with traditional supplies like coal gas and hydro

        Let it be so, an even playing field…… I dare them. 😉

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