UK Grid Operator to Tighten Power Interconnector Controls as Balancing Costs Rise
Britain's electricity system operator said on Thursday it will increase its use of day-ahead restrictions on cross-border power flows from next week as it seeks to protect grid stability amid changing supply patterns and rising balancing costs.The National Energy System Operator said it will begin using Day Ahead Net Transfer Capacity restrictions more regularly from the operational day starting July 24, with the measures designed to ensure sufficient system security when intraday options cannot provide enough certainty.The restrictions allow NESO to reduce the amount of electricity that can flow across certain interconnectors before the trading day begins.The mechanism will initially apply to four links where DA NTC controls are available, including North Sea Link that links with Norway, Viking Link with Denmark, NEMO with Belgium and ElecLink with France.The move comes as Britain's power system faces growing operational complexity from increased renewable generation, higher levels of embedded generation and volatile weather-driven demand.NESO said that DA NTC restrictions may be required to guarantee the security of the GB system, should available intraday options not provide this certainty.The operator said restrictions will be calculated using day-ahead forecasts and planned system conditions, with any unused capacity released later through intraday markets if conditions improve.The company said it will reassess restrictions to ensure capacity reductions are distributed fairly across eligible interconnectors, as additional mechanisms become available closer to real time, including Intraday Trading Limits on IFA, IFA2 and BritNed.NESO said restrictions will be applied equitably based on each interconnector's declared capability, while details of all restrictions will be published through the operator's public data portal.Britain's electricity balancing costs climbed to 302 million British pounds ($402 million) in June, up 64 million British pounds from May but down 28 million British pounds compared with the same month last year.The increase from May was driven by higher wind curtailment, warmer temperatures during the second half of the month and increased system requirements as demand patterns shifted.Constraint costs remained the largest component of spending, with thermal constraint costs reaching 181.3 million British pounds, while voltage-related costs totaled 34.3 million British pounds and inertia costs were 8 million British pounds.Non-constraint costs rose by 8 million British pounds, reflecting higher spending on operating reserves and restoration services, as well as a greater volume of balancing actions.The most expensive day of the month was June 28, when balancing costs reached 23.4 million British pounds. Constraint payments accounted for 19.8 million British pounds, representing about 85% of total daily spending.Average daily balancing costs increased to 10.1 million British pounds, about 2.4 million British pounds higher than May, as the absolute volume of balancing actions rose by 450 gigawatt-hours.Constraint costs increased 34%, while non-constraint costs rose 11% compared with the previous month. Action volumes increased 17% for constraints and 15% for non-constraint actions.