Solar power surge threatens to throw Britain’s grid off balance
Britain’s electricity network is forecast to be swamped with so much solar energy this summer that the system operator may have to issue unprecedented warnings for power stations to switch off.
The National Energy System Operator (Neso) said that an increasing number of solar farms and other power plants that feed electricity directly into regional networks were expected to reduce demand on the national network to a record low, breaking the previous record set during the pandemic in 2020.
The system operator needs to have a certain volume of flexible power sources running on the national network at all times to enable it to balance the system second-by-second and prevent blackouts. If national demand is very low, there may not be enough of these flexible plants operating and Neso said it may have to issue notices of a “negative reserve active power margin”.
These warn the market that “greater flexibility will be required to balance the electricity network” and that there is “the potential for emergency instructions”, which would involve inflexible power plants being ordered to disconnect from the grid. A negative reserve notice has never been used at a national scale before and only a handful of times at regional level.
However, it is looking more likely this year after the installation of more solar panels around Britain has resulted in solar energy repeatedly setting new records for maximum output already this year.
In 2020 electricity demand plummeted because of lockdowns during the coronavirus pandemic and the system operator issued a similar warning that it might have to issue negative reserve notices. It did not ultimately do so, however, instead negotiating a bespoke deal with EDF’s Sizewell B nuclear plant on the Suffolk coast to reduce its output through the summer months, freeing up space for more flexible generation such as gas plants to run.
“Operating at low demands requires careful balancing by Neso’s expert control room engineers, to ensure that supply does not outstrip demand, whilst also ensuring that the national electricity network receives a minimum continual flow of electricity to maintain its optimal operation,” Neso said.
It said it had been working on new ways of securing the flexibility it needs from low-carbon plants and “has a greater ability now than in previous years to operate the national network at new record low demand levels”.