UK ENERGY LAW AND ELECTRICITY SYSTEM: POWER PURCHASE AGREEMENTS (PPAs)

1. Concept and Legal Function

A Power Purchase Agreement (PPA) is a long-term contractual arrangement under which an electricity generator agrees to sell, and an offtaker agrees to purchase, electricity produced by a specified generating asset or portfolio. In the UK, PPAs are particularly important for renewable generation because they provide a route to market, revenue certainty and, frequently, access to balancing, settlement and certificate-related services. The UK Government describes corporate PPAs as long-term agreements between generators and buyers such as suppliers, traders or businesses consuming electricity themselves.

A PPA must therefore be distinguished from a Contracts for Difference (CfD). A CfD is a separate statutory-policy mechanism implemented through a private-law contract with the Low Carbon Contracts Company, providing price stabilisation through payments against a reference price. A generator may have both a CfD and a PPA, with the PPA providing the physical/market route through which electricity is sold.

2. Principal UK Legal Framework

The legal architecture of PPAs intersects with the Electricity Act 1989, electricity-generation and supply licensing, the Balancing and Settlement Code (BSC), Ofgem regulation, REMIT/market-abuse rules, environmental regulation, planning and grid-connection arrangements. Contractual terms also operate against ordinary English contract law.

Key PPA provisions normally address contract duration, price, volume, forecasting, imbalance responsibility, metering, dispatch, curtailment, renewable certificates, guarantees of origin, change in law, force majeure, credit support, termination, liability and dispute resolution.

Long-term PPAs can transfer substantial market risk. A fixed-price PPA may protect a generator from wholesale-price volatility but expose the buyer to declining market prices. A floating-price or market-indexed PPA does the opposite. UK public-sector guidance recognises this distinction between shorter arrangements with greater market exposure and longer contracts capable of providing greater price protection.

3. Corporate PPAs and Renewable Investment

Corporate PPAs have become increasingly significant because businesses can contract for renewable electricity directly from projects. The UK Government's 2026 Corporate PPA policy work specifically considers how CPPAs can support business competitiveness, energy security and investment in low-carbon generation.

For project finance, the PPA may function as a principal revenue-supporting document. Lenders examine the creditworthiness of the offtaker, tenor, termination compensation, pricing formula, volume risk and change-in-law provisions before determining whether contracted revenues provide sufficient bankability.

4. Offtaker of Last Resort

The UK developed the Offtaker of Last Resort (OLR) mechanism because independent renewable generators could experience difficulty obtaining commercially acceptable PPAs. Introduced in 2015, it provides eligible renewable generators holding qualifying investment/CfD arrangements with access to a backstop PPA through a licensed supplier. The backstop arrangement can last no longer than 12 months.

Thus, UK law does not treat the PPA merely as an ordinary private contract: market-design legislation can intervene to preserve a route-to-market where financing and electricity-market participation would otherwise be impaired.

5. Case Law

Case 1: URE Energy Ltd v Notting Hill Genesis [2024] EWHC 2537 (Comm)

Facts: URE proposed a 25-year energy arrangement combining renewable electricity supply, energy-efficiency investment and power-sharing arrangements. The commercial model depended on a long contractual period so that URE could recover its investment.

Legal Issue: The litigation concerned the contractual and commercial consequences of the proposed long-term energy arrangement.

Judgment: The Commercial Court examined the parties' contractual relationship and the commercial structure surrounding the proposed long-term energy supply.

Legal Principle/Ratio: Long-duration energy contracts must be interpreted according to their actual contractual architecture and commercial context rather than being treated as simple commodity-sale arrangements.

Significance: The case demonstrates why UK PPAs must carefully allocate long-term investment, pricing and termination risks.

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

Facts: The dispute concerned photovoltaic projects involving renewable-energy accreditation, tariffs and PPAs. The contractual arrangements contemplated grid connection, commercial operation and the execution of a PPA.

Legal Issue: The court had to consider contractual obligations surrounding development and commercial operation of the renewable projects.

Judgment: The court analysed the detailed contractual obligations governing project development and implementation.

Legal Principle/Ratio: Renewable-energy projects depend upon interconnected contractual obligations; failure to obtain or implement required project rights can have significant contractual consequences.

Significance: The case illustrates the interaction between EPC contracts, grid access, renewable incentives and PPAs.

Case 3: Star Hydro Power Ltd v National Transmission and Despatch Company Ltd [2025] EWCA Civ 928

Facts: A 30-year hydroelectric PPA contained tariff-adjustment provisions and London-seated arbitration. The dispute concerned tariff adjustment and regulatory authority. The Court of Appeal granted an anti-suit injunction concerning foreign proceedings.

Legal Principle/Ratio: Carefully drafted arbitration and jurisdiction clauses in PPAs can have substantial procedural significance, including the English courts' supervisory jurisdiction over London-seated arbitration.

Significance: Although governed by Pakistani substantive law, the case is highly relevant to international PPA drafting and English arbitration practice.

6. Conclusion

UK PPAs occupy a hybrid position between private contract and electricity-market governance. Their importance extends beyond the sale of electricity: they allocate price, volume, balancing, regulatory, credit and project risks. The modern UK PPA is consequently a central legal instrument connecting renewable investment, corporate procurement, electricity-market liquidity, project finance and the UK's wider transition toward a low-carbon electricity system.