There are two things you are paying for when you buy electricity - the electricity itself and the guarantee that when you flip a switch you get power. Differen

There are two things you are paying for when you buy electricity - the electricity itself and the guarantee that when you flip a switch you get power. Different energy sources contribute unequally to that second important factor - the stability of the grid - and that has to be factored in somehow. Nuclear, gas, hydro-electric storage and buying from abroad provide that stability in the UK. How it's done - I've no idea - but it's not just a question of units of electricity. One way is to bring in more surge pricing however people like the predictability of stable prices.