Britain's electricity system will be capable of being powered solely by zero carbon sources of power by 2025 for periods at a time, National Grid ESO has said.
Ahead of the COP26 climate summit in November, the operator has released new analysis that shows the system will be capable of running free of fossil fuels in four years. This will be a key milestone for a zero carbon electricity system by 2035, the target laid out in the sixth carbon budget.
Currently, National Grid ESO’s control room does still need to draw on fossil fuels to deliver system reliability, managing properties such as voltage and frequency. This was particularly evident at the beginning of 2021, when cold weather and low winds led to the grid relying more heavily on gas and coal than usual, and power prices in the day ahead market and the Balancing Mechanism skyrocketing.
But generally the last couple of years have been a record period of growth for renewable energy, including coal staying off the grid for 68 days in 2020, the longest period since the Industrial Revolution.
In 2019, zero carbon electricity generation outstripped that derived from fossil fuels for the first time, and on 17 August that year, at 1:30pm clean generation hit the highest share ever seen at 85.1% (wind 39%, solar 25%, nuclear 20% and hydro 1%). A further record was broken on 12 February when zero carbon generators produced their highest ever output, hitting 28.8GW.
Beyond this, records have been set for the lowest carbon intensity on Easter Monday 2021, dropping to 39gCO2/kWh, and peak wind generation of 17.7GW on Friday 21 May 2021, as well as 2020 going down as the greenest year on record.
The UK is “leading the world in cleaning up our energy system”, said energy minister Anne-Marie Trevelyan, claiming that National Grid ESO’s new report shows that Britain is “on the cusp of achieving periods of 100% zero carbon electricity generation with no fossil fuels used".
"There’s still some way to go, which is why we are powering forward with our ambitious commitments to increase renewable power across the UK and invest in new, green technologies so that we build back greener from the pandemic and tackle climate change," she added.
National Grid ESO pointed to May 23 2020 as an example of how the ESO must transform to make the system ready for net zero, as the electricity market provided a near 100% zero carbon solution on that day, but to ensure system stability the operator had to pull back some wind and hydro and replace it with gas and biomass to provide sufficient inertia. As such, the fuel mix for the day was 83% .
It is running a Stability Pathfinder project to find new ways to source inertia, using technologies such as synchronous compensators, hydroelectric power stations or repurposed gas turbines.
Five companies have received contracts worth £328 million as part of the pathfinder, including Drax which successfully started providing inertia to National Grid ESO in July as part of the initiative. It is using the Cruachan hydroelectric pumped storage plant to provide the service without generating electricity.
“Our engineers are deploying innovative, world first approaches to transform how the power system operates, such as removing the need to draw on fossil fuel based generation for critical stabilizing properties,” added Fintan Slye, National Grid ESO's executive director.
“There’s still plenty of hard work ahead but it’s an exciting time and getting to this position has been a huge team effort from everyone across the entire energy industry.”