Dave Elliott: UK power demand, according to National Grid, has a typical summer daytime peak of around 30 GW, but at night can fall to 17 GW. At present there is around 42 GW of renewable capacity installed, supplying nearly 32% of UK electricity, and more is on the way; by 2020 there should be 46 GW and by around 2027 maybe 60 GW, on current plans. Not all this renewable capacity will deliver full power all the time, or at any one time. Over the last year, the average load factor for onshore wind turbines was 30%. For offshore projects it was 50%, while for PV solar it was just 10%. Even so, during summer nights there may soon, at times, be more output than is needed. Solar will, of course, be zero at night but it will peak in the daytime, so that renewables may soon sometimes supply a large part of daytime summer demand. Certainly by 2027, which is when the Hinkley Point C nuclear plant may start up, it is hard to see what will be done with the output from its 3.2 GW capacity at times, especially since demand for electricity is falling (by about 2% in 2016-17 and 15% in the last decade) and could fall even more if energy efficiency were taken seriously.
Physics World 31st Oct 2018 read more »