The message
from David Hansen contains these words:

The average wind farm in the UK will pay back the energy used in its
manufacture within six to eight months, this compares favourably
with coal or nuclear power stations, which take about six months.

I've no doubt said it before but I for one have no confidence in the
judgement or indeed the probity of anyone who would claim that 6 to 8
months compares favourably to about 6 months unless of course the
favourable outcome was 8 months.

--
Roger Chapman