Govt’s Wind Strategy Ignores Intermittency

By Paul Homewood

I have already looked at this, but let’s focus more closely on wind power:


Central to the strategy is an ambition to build offshore wind from 12GW to 50GW, along with an increase in solar power. Indeed these were really the only concrete promises; most of the rest of the strategy is little more than flimflam.



Technically, if you assume average outputs throughout the year, it should be possible to get to 95% of low carbon electricity by 2030, or close to it, with suitable assumptions about nuclear capacity:



The total annual generation above comes to 332 TWh, close to likely full demand.

But, of course, intermittent renewables don’t operate at the same rate all year round. I have analysed the daily offshore wind generation data available from the CfD database for last summer. The CfD database covers about 40% of the UK’s total offshore capacity, so should give a fairly accurate picture.



Over the three month period, daily loading ranged from 1% to 68%.

Demand in summer averages 32 GW. Let us assume that we have storage to manage intra-day fluctuations in supply and demand (a very big if!). On a typical summer’s day, with 50 GW of offshore wind, plus extra onshore, we could easily find ourselves with 15GW of surplus power – this will have to be either constrained, or sufficient storage set up to handle it. Even the planned 5GW of electrolyser capacity will only absorb part. (BTW – this 5GW will remain unused most of the year, making it wholly unviable economically).

At the other extreme, when wind power is near zero, we will only have about 13GW of low carbon capacity available. This will presumably mean firing up 20GW or more of gas-fired capacity, unless we plan relying on inter-connectors.

The power shortage on a windless winter day will naturally be far more critical. We can expect average daily demand to peak at at least 60GW, given extra demand for EVs and heating. With average wind speeds, the power mix would look like this, with low carbon sources making up about 35GW, leaving 25GW needed from somewhere else:


However, on the sort of windless days which are common in winter, when offshore wind is generating at less than 5% of capacity, we end up needing 48 GW from “somewhere else”:


We currently only have 30GW at most of gas power capacity, and much of this is due to close in the next few years. Yet there was no mention at all in the government’s new energy strategy of when or how any of this was going to be built.


April 22, 2022 at 09:34AM

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