POWER PURCHASE AGREEMENTS (PPAs) IN UK ELECTRICITY LAW

1. Introduction

A Power Purchase Agreement (PPA) is a contractual arrangement under which an electricity generator agrees to sell electricity, and a buyer agrees to purchase it, usually for an agreed period and under specified commercial conditions. In the UK, PPAs are important for renewable-energy financing, electricity-market participation, price management and securing routes to market. A buyer may be a licensed supplier, utility, trader or corporate consumer. UK Government policy recognises PPAs as an important mechanism for connecting independent generators with electricity markets.

PPAs are generally private-law contracts, but they operate within the wider statutory framework of the Electricity Act 1989, electricity-market rules, supplier licensing requirements, network codes and support mechanisms such as Contracts for Difference (CfDs).

2. Legal Structure of a PPA

A typical UK PPA addresses:

term and commencement;

quantity and delivery of electricity;

pricing and payment;

forecasting and imbalance risks;

metering and settlement;

renewable-energy certificates and guarantees of origin;

curtailment;

force majeure;

change in law;

termination and default;

credit support and security;

warranties and representations; and

dispute resolution.

The precise structure depends upon whether the PPA is a utility PPA, corporate PPA, sleeved PPA, onsite/private-wire arrangement or financial/virtual PPA. Government material distinguishes physical arrangements from virtual PPAs, which operate principally as financial hedging instruments.

3. PPAs and Project Finance

For renewable projects, a long-term PPA can provide predictable revenue and therefore improve bankability. Lenders may assess the purchaser's creditworthiness, payment obligations, termination provisions and price mechanism when evaluating project-finance risk.

However, the PPA does not eliminate electricity-market risks. Depending upon the contractual structure, the generator may remain exposed to imbalance prices, volume risk, negative pricing, curtailment, market-price movements and regulatory change.

The UK Government's Offtaker of Last Resort (OLR) mechanism was introduced to encourage competition in the PPA market. For eligible CfD generators, it provides a backstop route to market through a one-year PPA when commercial arrangements cannot otherwise be secured.

4. Interaction with Contracts for Difference

PPAs and CfDs are legally distinct. A CfD provides a public-support mechanism based on a reference price and strike price, while the PPA establishes the generator's commercial route to market.

The transition from the Renewables Obligation (RO) toward CfDs changed the contractual environment for renewable generators. The Court of Appeal considered this transition in Drax Power Ltd v Secretary of State for Energy and Climate Change [2014] EWCA Civ 1153. The case concerned the Government's renewable-support framework and the movement from the RO system toward CfDs.

The case demonstrates that private electricity contracts operate within a broader statutory energy-support architecture established by Parliament.

5. Case Law

Case 1: Star Hydro Power Ltd v National Transmission and Despatch Company Ltd [2025] EWCA Civ 928

Facts: A hydroelectric generator entered into a 30-year PPA with Pakistan's central electricity purchaser. A dispute subsequently arose concerning tariff adjustment and project costs. The PPA contained an arbitration agreement providing for London-seated arbitration in specified circumstances.

Legal Issue: The dispute principally concerned the interpretation and enforceability of contractual and arbitration arrangements surrounding the PPA.

Judgment: The Court of Appeal granted an injunction concerning foreign proceedings connected with enforcement of the arbitral award. The matter is now before the UK Supreme Court, where judgment is awaited.

Legal Principle/Ratio Decidendi: A PPA is capable of creating sophisticated contractual rights concerning tariffs, performance obligations, dispute resolution and arbitration. Its interpretation depends upon ordinary contractual principles together with the applicable statutory and regulatory framework.

Significance: Although the underlying electricity project was outside the UK, the case is particularly relevant to UK-law PPA drafting because it demonstrates the importance of arbitration clauses, tariff mechanisms and jurisdiction provisions.

Case 2: GPP Big Field LLP v Solar EPC Solutions SL [2018] EWHC 2866 (Comm)

Facts: The dispute arose from contractual arrangements relating to a photovoltaic project. The project documentation referred to a long-term tariff arrangement and a power purchase agreement as part of the project's commercial structure.

Legal Issue: The Commercial Court considered contractual obligations arising from the project documentation.

Judgment: The Court applied ordinary principles of contractual interpretation to the interconnected project agreements.

Legal Principle/Ratio Decidendi: Renewable-energy projects commonly operate through interconnected PPA, EPC, O&M and financing arrangements, requiring courts to examine contractual language and the commercial structure carefully.

Significance: The case illustrates the importance of ensuring that a PPA operates consistently with other project contracts.

6. Regulatory and Competition Considerations

PPAs must comply with applicable electricity-market and licensing rules. Where suppliers or traders purchase electricity, their regulatory obligations may affect settlement, balancing and route-to-market arrangements. Competition law may also become relevant where contractual arrangements restrict market access or create anti-competitive effects.

Consequently, PPA drafting requires coordination between contract law, energy regulation, competition law, financing requirements and market-settlement rules.

7. Conclusion

PPAs occupy an important position in UK electricity law because they connect electricity generation with commercial markets and project finance. They are primarily contractual instruments, but their operation is shaped by the Electricity Act 1989, licensing arrangements, market rules and government support mechanisms. Effective PPA governance therefore requires careful allocation of price, volume, balancing, curtailment, credit, regulatory and termination risks. As renewable generation expands, PPAs remain an important mechanism for providing generators with routes to market while enabling suppliers and corporate buyers to manage electricity procurement and price exposure.