I DON’T understand why the household has become the unit of choice for
measuring renewable electricity production when households account for less
than half of electricity consumption in Scotland (“Winds of change for
renewable energy use “, The Herald January 3).
I assume it’s a PR device to make the figures seem more impressive than
they actually are.
Another way of making “per household” figures more sound impressive is to
underestimate electricity consumption per household. WWF’s figures, which
the article quotes, are derived from a theoretical model which assumes
average annual UK household electricity consumption to be 3,790 kWh. This
is a mistake, confusing meters with households. A single household can have
more than one meter. Official statistics for 2013 show a Great Britain
household average of 4,065 kWh and a Scotland average of 4,435 kWh. The
model overstates the number of households supplied by 17 per cent.
But it gets worse. The model assumes equal electricity consumption in each
month. In December, domestic consumption is more than 20 per cent higher
than a notional average month.
The combined effect of these errors is to overstate the number of
households theoretically supplied by wind-generated electricity by nearly
40 per cent. The model assumes the average household uses around 320KWh in
December but the reality is more than 440.
I doubt if WWF intends to be deliberately misleading but nor do I think it
cares so long as it gets column-inches for its campaigning.
(Dr) Dave Gordon,
60 Bonhard Road,
Scone, Perthshire.
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