ZONAL VS NODAL PRICING SYSTEM DESIGN

Introduction

Zonal and nodal pricing are alternative methods of incorporating transmission congestion and geographical constraints into wholesale electricity prices. They are particularly important in systems with large volumes of renewable generation located far from major demand centres. In Great Britain, electricity continues to operate under a single national wholesale pricing model. Following the Review of Electricity Market Arrangements (REMA), the UK Government decided in July 2025 not to introduce zonal pricing and instead proceeded with a Reformed National Pricing programme.

Zonal Pricing

Under zonal pricing, the transmission network is divided into a limited number of geographical bidding zones. Electricity normally has one wholesale price within each zone, while prices between zones diverge when transmission capacity becomes constrained. Zone boundaries are generally designed around significant and recurring transmission bottlenecks.

The principal advantage is that zonal prices provide stronger geographical signals than a single national price without creating the operational complexity associated with thousands of individual nodes. They can encourage generators, storage operators and flexible demand to locate where their output or consumption provides greater system value.

However, zonal design creates difficult legal and regulatory questions concerning zone boundaries, boundary revision, congestion allocation, investment protection and distributional effects between regions.

Nodal Pricing

Nodal pricing, also known as Locational Marginal Pricing (LMP), establishes a separate wholesale price at individual network nodes. The price represents the marginal cost of supplying one additional unit of electricity at that specific location, taking account of generation costs, transmission congestion and, depending upon market design, electrical losses.

Nodal systems can therefore generate hundreds or thousands of simultaneously different prices. NESO explains that markets such as New Zealand, Singapore and parts of the United States use nodal pricing, while zonal systems operate in countries including Italy, Sweden, Norway and Denmark.

Zonal Versus Nodal Design

Nodal pricing offers greater geographical precision. Because congestion is reflected directly in individual nodal prices, generators and consumers receive detailed signals regarding where electricity is relatively valuable or costly.

Zonal pricing sacrifices some precision in return for greater simplicity. Internal congestion within a zone must still be managed through redispatch or balancing mechanisms because all participants within that zone generally face the same wholesale price.

Nodal pricing can therefore reduce reliance on out-of-market redispatch but may create greater price volatility, complexity and investment uncertainty. Zonal pricing can provide a compromise between national pricing and fully granular LMP.

Position in Great Britain

During REMA, the Government examined both approaches. Nodal pricing was removed from further consideration during the earlier stages of the review because the Government considered that its additional complexity and risks were not justified by sufficient additional benefits. Zonal pricing remained under consideration for longer.

In July 2025, however, the Government decided to retain a single GB-wide wholesale market. It considered that zonal pricing could potentially address congestion problems but raised concerns about changing zone boundaries, locational volume risk and uncertainty for investment.

The subsequent Reformed National Pricing programme instead focuses on measures including stronger locational network charges and strategic siting incentives. Ofgem was consulting on locational charging reforms during 2026.

Case Name/Citation – Bundesnetzagentur v ACER, Cases T-600/23 and T-612/23, EU:T:2025:927

Facts: The dispute concerned methodologies governing cross-zonal electricity capacity in the European Core capacity-calculation region, including whether internal network elements could be considered when calculating cross-border capacity.

Legal Issue: Whether ACER's approach to capacity calculation and internal critical network elements complied with EU electricity-market legislation.

Judgment: The General Court annulled the contested regulatory determination in the proceedings.

Legal Principle/Ratio: Cross-zonal capacity and congestion-management methodologies must comply strictly with the allocation of regulatory powers and the substantive requirements established by EU electricity-market legislation.

Significance: The case demonstrates that geographical electricity-market design is not merely economic modelling; bidding zones, congestion calculations and network constraints are subject to enforceable regulatory rules.

Case Name/Citation – Bursa Română de Mărfuri SA, Case C-394/21, EU:C:2022:527

Facts: Romanian legislation maintained monopoly arrangements concerning electricity-market intermediation.

Legal Issue: Whether those arrangements were compatible with EU electricity-market legislation governing day-ahead and intraday trading.

Judgment: The Court held that certain pre-existing monopoly arrangements were not automatically prohibited, subject to the requirements of the applicable EU framework.

Legal Principle/Ratio: Wholesale electricity-market architecture remains subject to statutory rules governing market organisation, competition and trading arrangements.

Significance: The judgment reinforces the principle that wholesale pricing structures must operate within legally authorised market institutions.

Conclusion

Zonal pricing provides regional congestion signals through a manageable number of bidding areas, while nodal pricing reflects system conditions at much finer geographical resolution. Nodal markets can improve dispatch precision but introduce greater complexity and locational price exposure. Zonal systems provide an intermediate solution but depend critically upon defensible zone boundaries and congestion-management rules. Great Britain has ultimately retained national wholesale pricing while developing stronger locational signals through network charging and wider market reform.