Between 1975 and 2019, photovoltaics dropped in price some 500 times – to under 23 cents per watt of power.3 The bulk of that change has come in the last decade. Even in 2010, it cost 30–40 cents (about 20–30 pence) to produce a kilowatt-hour of electricity using solar panels, making it 10–20 times more expensive than fossil fuels.4 But the cost of solar power has been declining at exponential rates – about 40 per cent per annum for large commercial contracts.
