CurveBlock
The National Grid Electricity System Operator (ESO) manages system balance across transmission and, through coordination with distribution network operators, influences when and how generators are asked to reduce output. Curtailment arises when local or system‑wide constraints mean generation must be reduced to protect network stability. For intermittent renewables, curtailment reduces expected output and can increase revenue volatility, particularly for assets without firm price support.
The ESO’s scheduling and balancing actions interact with settlement arrangements in the wholesale, imbalance and constraint markets. Payments to curtailed generators depend on contractual arrangements—some projects hold firm contracts such as Contracts for Difference (CfDs) or Power Purchase Agreements (PPAs) that mitigate merchant exposure, while others receive limited compensation when curtailed. Investors should note whether a project’s revenue model anticipates frequent curtailment and how flexibility services or storage are deployed to capture otherwise lost value.
Network investment and connection agreements also play a role: reinforcement decisions and the prioritisation of connections affect future curtailment risk for clusters of generators. For projects intending to deliver stable cashflows, secured offtake agreements and access to flexibility markets are key mitigants.
For retail investors considering fractional exposure to renewable assets, assessing a project’s vulnerability to balancing actions and the presence of contractual protections is as important as the headline generation capacity. Clear disclosure of curtailment risk and the arrangements for compensation or flexibility integration helps savers compare offerings on an apples‑to‑apples basis.