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2020 Greenest Year Ever for UK Electricity Grid


The carbon intensity of the UK’s power grid reached a new low last year, continuing a trend that has seen emissions from the electricity system fall by 66% since 2013.

The carbon intensity of the grid—the emissions associated with every kilowatt-hour of electricity consumed—averaged 181gCO2/kWh across 2020, according to data released by the National Grid Electricity System Operator (ESO). That’s compared to an average of 215g in 2019 and 248g in 2018.

The low carbon intensity of the grid was driven by bumper year for renewable generation, with wind and solar power installations benefitting from new capacity, favourable weather conditions and electricity demand dampened by the pandemic.

Wind power broke records for its highest level of generation several times during the year, most recently on 18 December, contributing 17.2GW of electricity. On 26 August, as the UK was lashed by Storm Ellen, wind power achieved its largest-ever share of the electricity mix—59.9%.

Solar power also set records, for its highest level of generation, 9.7GW on 20 April and its highest share of the electricity mix (34%) on 30 May. Solar power provided more than a third of the country’s electricity on several occasions in May, taking advantage of clear air during the spring lockdown.

With renewables generating so much power, the UK’s remaining coal power plants were offline for a record 1630 continuous hours, or nearly 68 days between 10 April and 16 June. 

This coal-free stretch contributed to making May the greenest month ever for the UK's electricity grid, with carbon intensity averaging 143 gCO2/kWh throughout the month. On 24 May the carbon intensity of the system dropped to the lowest level ever seen: 46 gCO2/kWh.

In total, the UK was powered without coal for more than 5,147 hours in 2020, including the first-ever coal-free Christmas Day. In comparison, there were just to 3,666 coal-free hours in 2019, 1,856 in 2018 and 624 in 2017. 

Overall, coal made up just 1.6% of the electricity mix last year, compared to nearly a quarter five years ago.

Rob Rome, interim head of national control at National Grid ESO, said: “2020 has been a record-breaking year for Great Britain’s electricity system. The grid continues to transform at an astonishing rate as we move away from fossil fuel generation and harness the growth of renewable power sources."

He suggested that last year’s milestones place the electricity grid on track to meet its goal of achieving carbon-free hours—without either coal or natural gas generation—by 2025.

“That 2025 ambition is a stretching target. Last year gave us a flavour of some of the challenges ahead, as our control room worked 24/7 to operate the electricity system in unprecedented conditions.

“But I’m proud to say every action we’ve taken has delivered safe, secure and reliable low carbon electricity at the same time as minimising costs for consumers.”

Lauren Smith
Lauren Smith

Lauren Smith has worked as a journalist and copywriter for most of the last decade, covering technology, energy, and consumer rights, in the US and UK.

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