Q4 2020: Renewables overtake fossil fuels

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Dr Iain Staffell, Professor Richard Green, Professor Tim Green, Professor Rob Gross and Dr Malte Jansen -Imperial College London

Ten years ago, fossil fuels provided three quarters of Britain’s electricity, some 20 times more than renewables. 

 In 2020 their roles reversed, and renewables overtook fossil fuels for the first time to become Britain’s biggest source of electricity over the whole year.  Together wind, solar, hydro and biomass provided 104 TWh of electricity, or 39% of all consumed.

The pace of change has been dramatic. Renewable output has increased ten-fold since 2010, while fossil-fuelled output has fallen 60%.  In 2020, supply from coal, gas and oil fell to below 100 TWh for the first time since 1960.

The demise of fossil fuels for generating electricity in Britain

Meanwhile, 2020 saw the fastest year-on-year rise in electricity generation from renewables, boosted by growth in the offshore wind fleet and ‘good weather’ for energy generation (sunny and wind).  With demand falling due to COVID, the share of renewables in the grid mix rose by 5 percentage points, mirroring the 6 point fall from fossil fuels.

Fossil fuels were overtaken by low-carbon electricity sources in Britain (nuclear plus renewables) back in 2017. The milestone of renewables alone outperforming fossil fuels was bound to happen at some point, but it likely arrived 1–2 years early because of the coronavirus pandemic. Over the last decade demand has fallen by 1–2% each year. With the 5.5% drop seen in 2020, around 15 TWh of demand was ‘missing’ because of lockdowns. That is like the whole of Wales going without power for the year.[^1] With only 4 TWh separating the output of renewables from fossil, this reduced activity made all the difference.

The growth of renewable electricity generation in Britain, showing the share of electricity generation over the year [left] and the number of days per year that renewables produced more than fossil fuels [right]

The first time that renewables supplied more electricity than fossil fuels over a single day was back in the summer of 2015. Last year, this was the case for over 200 days – well over half of the year. The fact this number has almost doubled since 2019 highlights the pace of change. If this pace were to continue, we could naively expect that unabated fossil fuels will be all but eliminated by 2030. This would be no small challenge, as the power system must work equally well when it is sunny and windy as it does on a cold and still winter’s day – or even several of them in a row. But if the last decade has taught us anything, it is that the realms of what is possible are expanding every day.

[1] Wales consumed 15 TWh of electricity in 2019 across all sectors.

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