POWER PURCHASE AGREEMENTS (PPAs): STRUCTURING AND REGULATION IN UK ELECTRICITY LAW

1. Introduction

A Power Purchase Agreement (PPA) is a long-term contractual arrangement under which an electricity generator agrees to sell electricity, and an offtaker—usually a licensed supplier, trader, corporate consumer, or utility—agrees to purchase it. PPAs are particularly important for renewable projects because they provide revenue certainty, facilitate project financing, allocate operational risks, and establish the commercial route to market.

In the UK, PPAs operate within the wider framework of the Electricity Act 1989, electricity licensing requirements, the Balancing and Settlement Code (BSC), grid and connection arrangements, competition law, and renewable-support mechanisms such as Contracts for Difference (CfDs). Licensed participants must comply with applicable industry codes governing activities such as supplying and moving electricity.

2. Principal Elements of PPA Structuring

A carefully structured PPA normally addresses:

1. Contracted Capacity and Quantity – specifies the generating capacity, delivery profile, minimum volumes, and treatment of excess or shortfall electricity.
2. Pricing Mechanism – may provide a fixed price, indexed price, market-linked price, floor price, or a hybrid structure.
3. Term and Commencement – renewable PPAs frequently correspond with the project's financing period and operational life.
4. Metering and Settlement – establishes the measurement methodology and responsibility for imbalance and settlement costs.
5. Balancing Risk – determines whether the generator, offtaker, or intermediary bears costs arising from deviations between forecast and actual generation.
6. Renewable Attributes – contractual treatment of Renewable Energy Guarantees of Origin (REGOs) and other environmental attributes must be expressly addressed.
7. Curtailment and Grid Constraints – determines payment consequences when electricity cannot be exported because of network limitations.
8. Force Majeure and Change in Law – protects parties against specified events beyond their reasonable control and regulatory changes.
9. Default and Termination – includes payment default, insolvency, prolonged force majeure, licence loss, and material breach provisions.
10. Dispute Resolution – may provide for negotiation, expert determination, arbitration, or court proceedings.

The increasing sophistication of electricity markets also means that PPA structures must interact with BSC arrangements. Recent Ofgem decisions demonstrate continuing regulatory adjustment of settlement and trading arrangements.

3. Regulatory Architecture

The UK does not generally impose one standard statutory PPA form for ordinary commercial transactions. Instead, contractual freedom operates alongside mandatory electricity regulation. Ofgem/GEMA regulates licensed activities, while industry codes establish important technical and commercial obligations.

For renewable generators holding a CfD, the contractual position is different from an ordinary merchant PPA. The CfD provides a separate government-backed revenue-support mechanism. Ofgem continues to determine disputes concerning CfD allocation and prequalification under the relevant statutory framework.

The Offtaker of Last Resort (OLR) scheme is particularly relevant. It was introduced to promote availability of PPAs for eligible renewable generators unable to obtain ordinary commercial PPAs. It facilitates a backstop PPA with a licensed supplier, normally for a period of no more than 12 months.

4. Important Case Laws

Case 1: Arnold v Britton [2015] UKSC 36

Facts: The dispute concerned interpretation of contractual service-charge provisions in long-term leases.

Legal Issue: How should courts interpret detailed commercial contractual wording?

Judgment: The Supreme Court emphasised the importance of the actual contractual language, while considering the commercial context.

Legal Principle/Ratio Decidendi: Courts should not rewrite an agreement merely because its commercial consequences appear unattractive.

Significance: PPA drafting must therefore state pricing, volume, termination and risk-allocation mechanisms with exceptional precision.

Case 2: Wood v Capita Insurance Services Ltd [2017] UKSC 24

Facts: The case concerned interpretation of an indemnity provision in a commercial acquisition agreement.

Legal Issue: How should apparently difficult contractual language be interpreted?

Judgment: The Supreme Court adopted a balanced approach considering both contractual language and commercial context.

Legal Principle/Ratio Decidendi: Contract interpretation involves identifying the meaning conveyed by the agreement read as a whole, rather than mechanically preferring either literal wording or commercial purpose.

Significance: This is highly relevant to PPAs containing interconnected provisions concerning forecasting, indemnities, imbalance, termination and regulatory risk.

Case 3: Cavendish Square Holding BV v Makdessi [2015] UKSC 67

Facts: The dispute involved contractual provisions imposing financial consequences following breach.

Legal Issue: Whether contractual financial consequences constituted unenforceable penalties.

Judgment: The Supreme Court reformulated the modern approach to contractual penalties.

Legal Principle/Ratio Decidendi: The court examines whether the relevant provision protects a legitimate contractual interest and whether the consequence imposed is unconscionable or disproportionate.

Significance: PPA termination payments, liquidated damages, performance security and imbalance-related charges should therefore be carefully proportioned to legitimate commercial interests.

5. Conclusion

UK PPA regulation is therefore a hybrid framework: commercial contractual freedom operates within mandatory electricity-market rules, licensing requirements, industry codes, renewable-support mechanisms and general contract law. Effective PPA structuring requires precise allocation of price, volume, balancing, curtailment, environmental attributes, regulatory change, default and termination risks. The continuing evolution of the BSC further demonstrates that PPAs must be drafted as part of the wider electricity-market architecture rather than as isolated commercial contracts.