This revolution is driven not by green ambitions but by falling prices. The best solar offered “the cheapest electricity in history”, said the IEA in 2020, and it’s much cheaper now. Prices of panels have dropped 99.3 per cent since 1975, and by 95 per cent just since 2007, reports Our World in Data. And prices continue to fall, as China exports surplus panels — often older, simpler models — to Africa in particular.