Solar PV versus Other Energy Sources
Solar PV (Solar Photovoltaics) only generates a small fraction of quoted design output in UK conditions over the course of a yearly cycle.
The chart below is a comparison of various energy generation systems over time, comparing actual performance with designed capability.
The key facts about Solar PV efficiency are:
Solar PV will be available whenever it has power to sell. Solar PV output is very low in the winter months, with the average daily output being around 10% of the peak summer output.
Off-shore and on-shore wind will be available when the wind blows. It blows more at sea so the available wind to be captured is greater off-shore and the generators are better.
Nuclear will provide some of the baseload, but its output cannot be readily raised and lowered to compensate for changes to output from wind and solar.
Gas powered power stations therefore have to be used fill in when solar and wind power output is insufficient to meet the demands of the national grid.
Over investment in Solar will result in more gas fired power stations having to be run in the winter when Solar output is consistently low.
Data shows this as a consistent factor over 5 years of monitoring. See this link for full details.