CurveBlock
A PPA is a commercial contract under which a generator sells electricity to a buyer at an agreed price and duration. For small-scale UK solar projects common structures include sleeved PPAs via a supplier or aggregator, corporate offtaker agreements with a private buyer, and short-term merchant arrangements using supplier-backed products. Contract length, indexation clauses and gate clauses that link payment to metered delivery shape revenue predictability.
Price mechanisms vary from fixed-price long-term deals to formulas indexed to wholesale power, seasonal differentials or market price benchmarks. Fixed-price PPAs give predictable cashflows but may include step-up/down clauses and exposure to supplier credit. Index-linked arrangements protect generators from inflation but expose them to wholesale volatility. Small projects often rely on intermediary counterparties — aggregators and suppliers — which introduces counterparty concentration and insolvency risk if a supplier fails.
Counterparty creditworthiness is a central underwriting factor. Long-term offtakers with strong credit profiles reduce revenue risk, while shorter duration or merchant sales increase exposure to price and balancing costs. Contractual provisions such as collateral, parent company guarantees and termination compensation also alter expected outcomes.
For retail investors considering fractional exposure to solar projects, the PPA terms are a primary driver of income reliability. Understanding whether a project has long-term offtake, who the counterparty is, and how pricing is calculated helps investors assess cashflow stability and the potential need for reserve funding when revenues underperform.