The power rating of solar panels is derived differently to conventional turbines. A 1 MW (megawatt) turbine delivers 1 MW under full output in real-world conditions.
But the claimed rating of a solar panel is derived by measurements in a lab applied to a mathematical formula and therefore is very theoretical.
Worse still, the output of installations below 30 kW (kilowatts) is estimated and no meters need be read. This includes virtually all domestic rooftop arrays.
So the estimated electric production doesn’t account for reduced output due to incorrectly installed arrays, dust build-up, frost, snow, shade and panels which don’t face south (in my neighbourhood there are north-facing ones).
There are undoubtedly arrays out there which produce nothing but will get the index-linked payments for 20-25 years.
Thus nobody really knows how much energy is produced by Britain’s solar fleet. DECC claims that in 2014 solar produced 1.1 per cent of the UK’s electricity consumption but I take that with a pinch of salt. Energy secretary Amber Rudd is quite right.