Renewable energy is GREAT - it's zero-carbon and provided free of charge by Mother Nature! However, the UK - contrary to some press reporting e.g. the coal free fortnight - doesn't produce very much of it … which can be explained as follows: although the media tend to use the term 'energy' and 'electricity' interchangeably, they're not.
"On 14 May, Britain generated a quarter of its energy from the sun - the largest proportion yet." gushed the BBC
BBC News Website
31 May 2019
Electricity is the smallest of three broad categories of energy production/supply and renewables contribute around 25% to electricity generation - as shown in the latest (2018) official figures published by the Department for Business, Energy & Industrial Strategy
Here's the breakdown:
- Gas - largely used for heating - 44 units
- Electricity - many uses - 30 units, of which
- 7 units from hydro, wind and solar PV
- Bio-fuels (4 units)
- Balance from gas, nuclear, coal
- Petroleum products - largely used for transport - 77 units
Electricity can be used for heating (e.g. heat pumps) and electricity can be used for transport (electric trains, electric cars); the figures above show there is a huge shortfall perhaps by an order of magnitude which not only would cost a great deal to build, but also create logistical problems with the stability of the grid, if it were.
Presently our National (electricity) Grid compensates for renewables' intermittency to balance supply and demand by managing output from Combined Cycle Gas Turbine power stations (the work-horses of UK electricity generation) and the relatively few still operating coal-fired power stations. When these all close in 2025 grid stabilisation will become harder and power shortages are a real possibility.
Without fossil-fuelled power generation to prop-up renewables, some other measure is needed to shave the peaks and fill the troughs of supply - storage is one possibility, but it is incredibly difficult and costly even at renewables' present day 25% contribution. Could you devise a storage strategy to balance variations in wind and solar PV to within +/- 1000 MW of the average 6700 MW (actual 2019 figures)?
Have a go!