National Grid PLC has called on Britain's energy regulator to review the amount of backup generating capacity that is kept in reserve to prevent widespread power cuts such as those that hit parts of the country in early August.
The company, which operates the transmission network and is also responsible for balancing supply and demand, urged the Office of Gas and Electricity Markets, or Ofgem, to determine whether it needs to provide for "higher levels of resilience in the electricity system."
The suggestion came as part of a detailed report into the Aug. 9 cuts, which saw more than a million customers lose power after a lightning strike on the electricity network caused an offshore wind farm, a gas-fired power plant and a host of smaller renewable generators to disconnect from the system. The resulting drop in frequency triggered cuts to rail services, a hospital and Newcastle International Airport.
"While the processes and procedures in place ... generally worked well to protect the vast majority of consumers, there was however significant disruption," National Grid wrote in the report. "Therefore, reflecting on the scale of disruption caused to the public, there are some areas where we believe a wider review of policy, processes or procedures may be appropriate."
Ofgem is investigating the actions of National Grid in connection with the power cuts, along with Britain's 12 distribution network companies and utilities Ørsted A/S and RWE AG, operators of the wind farm and gas plant, respectively. All of the companies could face a fine of up to 10% of their regulated U.K. revenue if they are found to have violated their license conditions.
National Grid is also under investigation by the government over its role in the incident, which has raised pressure on the company as it faces broader threats to its business model in the U.K. After the power cuts, Britain's energy minister even suggested stripping the company of its role as system operator.
Batteries and other flexible generation, which get paid for providing frequency response services, jumped into action after the generators tripped offline. But Ofgem's current standards mean that National Grid only needs to have sufficient backup power in reserve to provide for the loss of the largest generator connected to its network on any given day — at approximately 1 GW, this was far less than the nearly 1.7 GW of capacity that disconnected after the lightning strike.
In its report, National Grid also recommended a review of the list of critical infrastructure, such as hospitals and transport networks, that risk being disconnected when network frequency drops below manageable levels.
It also suggested speeding up the ongoing overhaul of protective systems at smaller generators connected to the distribution system to ensure the plants don't trip as easily in the future. Richard Black, director of the Energy and Climate Intelligence Unit, a London-based climate change think tank, noted that fixing oversensitive sensors more quickly would be a logical step.
"The industry has been aware of this for at least 10 years, and yet under current plans it won't be fixed until 2022, which the report suggests is inadequate," he said.
