I am surprised to see Paul Moore trying to revive the idea that every wind turbine needs a fossil fuel back-up to be kept running at full capacity (29 August, page 28) when research into intermittent generation by the UK Energy Research Council is easily accessible.

Running at about a quarter of capacity, the government's proposed 35GW of wind, equates to 9GW, about 20% of electricity supply. There is already reserve generation capacity to cope with nuclear plant failures and similar events, so the additional reserve required is under 10% of the wind generation. Costs for grid balancing and maintainance would be under 1p/kWh.

It seems that taking into account carbon prices, price volatility, pollution and lack of fossil and nuclear fuel availability, adding 35GW of wind capacity and paying for the small backup required is a sound economic decision and good risk management.

Simon Reynolds