The annual cost of curtailment could rise to more than £3 billion by the end of the decade, before falling when major infrastructure projects unlock bottlenecks on the grid. The Electricity System Operator (ESO) has warned that delays to National Grid’s so-called ‘Electricity Superhighways’ could see these costs rise even further. The figures are revealed within the ESO’s inaugural Balancing Costs assessment, which forecasts a steep rise in the total cost of balancing the grid until 2030.