National Grid ESO reflect on the greenest ever day on the electricity grid

Julian Leslie, Head of Networks at National Grid ESO

For those interested in how electricity in Great Britain is changing there was some good news to round off the Easter holiday. At lunchtime on Easter Monday the carbon intensity of electricity – the measure of CO2 emissions per unit of electricity consumed – dropped to 39 gCO2, the lowest figure on record.

It’s a trend we’ve seen coming, carbon intensity of electricity has dropped by almost 66% in the last seven years, but nevertheless it’s exciting to see new milestones such as this.

Last Monday the sunny spells and blustery conditions, coupled with low demand driven by the Easter holiday, meant renewable sources of power dominated the electricity mix. At 1pm wind power made up 39%, solar 21%, and nuclear 16% – meaning zero carbon sources made up almost 80% of the nation’s electricity.

"Getting to this position has been a huge team effort from everyone across the entire energy industry. It’s proved that you can take an energy system with little renewable generation and transform it into a cleaner and greener system with deliverable plans for zero carbon operation."

The previous carbon intensity record of 46 gCO2/kWh was set on May 24 2020 - part of what was a record-breaking year for GB electricity. When I first joined National Grid in 1989, we were still reliant on large coal-fired power stations to generate electricity for the country. That was simply how electricity was generated. During spring 2020 Britain saw its longest run since the industrial revolution generating electricity without using coal, stretching almost 68 days (1,630 hours) between April 10 and June 16. In total coal generated only 1.6% of the electricity mix in 2020, compared with almost 25% five years ago.

The last 18 months has also been record-breaking for renewable power sources. The record for the highest ever level of wind generation was broken on 13^th February 21 (17.5GW) – while August 26 last year saw wind contributing its highest ever share to the electricity mix (59.9%).

Solar power, too, set new records for its highest ever level of generation (9.7GW) and its highest share in the mix (34%) – comfortably providing a third of Britain’s electricity supplies on several occasions in May 2020. These milestones are important as we look towards 2025 and our ambition (when there is enough zero carbon generation available in the market) of being able to operate the electricity system from entirely zero carbon sources.

The UK has been at the forefront of change, and as part of the journey to COP 26, we’ll be working with partners across the world to discuss how we can all accelerate decarbonisation and learn from each other’s experiences.