Letter: Questions about back-up for renewable energies answered

He asks several questions and mistakenly suggests I was berating power plants for failing when I was emphasising the reality that unexpected power failures are largely confined to non-renewable capacity whereas renewable generation is much more easily anticipated and planned for.

Chris appears to try to confuse the issue by referring to metallurgy (here metal aging) when many of the documented shutdowns I identified are unrelated to metallurgy. Even Owen Paterson MP has warned of the risk posed by big plants falling off the grid rising further if EDF build it 3.2GW nuclear plant at Hinkley Point.

Chris asks "Where is the National Grid's back-up?", although probably already knowing the answer. Currently it is typically fossil-fuelled as he suggests and will continue to be for some time.

Chris further asks: "It's night and there is no wind and yes we have had times like that, just where does the power come from?" Stating initially the obvious much fossil generation is already in place but there are opportunities to develop further combined heat and power, biogas (anaerobic digestion), biomass, geothermal, hydro, and tidal. There are also opportunities to further develop interconnectors, which already help connect the UK with France, the Netherlands, Northern Ireland and the Republic of Ireland. In this way power can be imported or exported.

One could equally ask the same question of such countries which are already further down the path to greater renewable contributions to their energy supply who don't switch off their supply at night.

In Germany renewable sources accounted for some 31 per cent of the net electricity production in the first half of 2014. Spain has a target of generating 92 per cent of its energy needs from renewable sources.

Chris might find stimulation in reading Sustainable Energy – without the hot air by David MacKay and Zero Carbon Britain: Rethinking the Future.

The latter outlines the zero carbon Britain scenario showing that we could rapidly reduce UK greenhouse gas emissions to net zero by 2030.

Robert Saunders, Apley