The Electricity System Operator (ESO) has awarded contracts to three offshore wind farms to provide an intertrip service to help manage constraints across the EC5 transmission boundary in East Anglia.
The service will avoid the need to pre-emptively curtail generators when a constraint emerges by allowing the ESO to rapidly disconnect, or reduce output from, the contracted wind farms if a network fault occurs.
The “early-start” contracts have been awarded as part of the ESO’s Interim Constraint Management Intertrip Service (CMIS) for the EC5 boundary, which encloses large parts of East Anglia and multiple offshore wind farms. The ESO has procured 918MW of intertrip capacity across 10 units from Orsted’s Gunfleet Sands offshore wind farm, RWE’s Galloper and Equinor’s Dudgeon. The generators will receive fees for both arming when a relevant constraint emerges and tripping when a fault occurs.
The interim service, which will begin this month and run until March 2025, is expected to save £20 million through reduced curtailment costs. In November, the ESO launched an enduring intertrip service for the EC5 boundary, which is due to begin in April 2025 and is forecast to save hundreds of millions of pounds.
The ESO has been using an intertrip service to manage constraints across the B6 boundary between Scotland and England since April 2022. It says that service has already saved more than £95 million for consumers and enabled 367GWh of extra renewable generation.
Julian Leslie, director of strategic energy planning and chief engineer at National Grid ESO, said: “The constraint management intertrip service is fundamental towards solving a heavily constrained area of the grid, reducing balancing costs.
“The ESO is driving forward innovative solutions to manage constraints on the system, whilst maximising our ability to utilise renewable generation, supporting the journey to 100% zero carbon operations by 2035.”