The line graph illustrates how much electricity the UK generated from coal, gas and wind between 1990 and 2020, measured in terawatt-hours.
Overall, coal went from being the dominant source to a negligible one, while wind power grew from almost nothing to a significant contributor. Gas rose over the period as a whole, although it fluctuated along the way.
Coal output stood at 200 TWh in 1990 and fell steadily to 120 TWh in 2000. After a small recovery to 125 TWh in 2005, it dropped sharply, reaching just 6 TWh in 2020. Gas followed a very different course. Starting at a mere 2 TWh, it climbed to 125 TWh in 2000 and peaked at 150 TWh in 2005. It then declined to 60 TWh in 2015 before recovering to 125 TWh by the end of the period.
Wind generation was virtually non-existent for the first fifteen years, at no more than 3 TWh in 2005. From 2010 onwards, however, it expanded rapidly, rising from 10 TWh to 40 TWh in 2015 and then to 75 TWh in 2020, which meant that wind output was by then far higher than that of coal.