The Electricity Network Strategy Group's call for the spending of almost £5 billion to upgrade the UK electricity network (your report, 5 March) seems to ignore the fact that most renewable generation sources are highly variable. So, for much of the time, the upgraded network will not be carrying the extra current.
In the case of wind-powered generation, there will be, on average, no output for about two-thirds of the time. As a result, the "capacity credit" of 11.4GW of installed wind-powered generation is only 3.3GW.
It seems somewhat reckless to spend so much money on making provision for transmitting a highly variable and unpredictable electricity supply, indeed, one that will need to be backed up by thermal generation when it is unavailable.
