Curtailment, Derating and Small Generators: What Ofgem’s Framework Means for Project Revenues

Curtailment occurs when system operators or network companies instruct generators to reduce output for system security or network constraints. For small distributed assets, repeated curtailment or so‑called derating (where a generator cannot be relied upon for full capacity) reduces expected energy volumes and therefore merchant revenue. Ofgem’s frameworks for distributed generation set the principles that govern who bears curtailment costs and how compensation mechanisms operate.

Ofgem has long emphasised economic signals and efficient use of the network: locational constraints, network charging methods, and the design of balancing and constraint payments all shape the marginal economic return for small projects. Generators can sometimes access network reinforcement or negotiate commercial arrangements, but the costs and timelines for securing more permissive access can be material for smaller projects.

For retail investors in fractional renewable projects, clarity on curtailment exposure and contract terms is essential. Investment documents should explain how curtailment is managed, whether compensation or prioritisation clauses exist, and how expected revenues are stress‑tested under different network scenarios. When fractional ownership is underpinned by transparent modelling of curtailment and derating risk, individual savers can better assess the trade‑off between higher yields on decentralised projects and potentially greater volume volatility.