COLLUSION RISKS IN ELECTRICITY AUCTION SYSTEMS

1. Introduction

Collusion risks in electricity auction systems arise when generators, traders, suppliers, or other market participants coordinate their bidding behaviour instead of competing independently. Electricity auctions are used in day-ahead markets, balancing markets, capacity mechanisms, renewable-energy procurement, transmission projects, and other competitive allocation processes. Their effectiveness depends upon genuine rivalry between bidders.

Collusion can distort price discovery, increase electricity costs, reduce market efficiency, and undermine confidence in energy regulation. Because electricity markets may contain relatively few major participants that repeatedly interact, they can present structural conditions in which coordinated conduct becomes particularly important for competition authorities to monitor.

2. Forms of Collusion

Collusive behaviour may take several forms. Competitors may agree which participant will submit the winning bid while others submit deliberately unattractive offers. This is commonly known as bid rigging or cover bidding. Firms may also coordinate minimum bid prices, divide customers or geographic markets, rotate successful bidders, restrict available capacity, or exchange commercially sensitive bidding information.

The CMA explains that cover bidding involves competitors secretly arranging for one or more firms to submit deliberately high or otherwise uncompetitive bids so that a designated bidder is more likely to succeed. Such conduct removes genuine competitive pressure and can lead to higher prices.

3. Why Electricity Auctions Are Vulnerable

Electricity markets can present several characteristics associated with coordination risk. These include market concentration, repeated interaction between the same generators, relatively homogeneous products, transparent market information, capacity constraints, and predictable demand patterns.

Repeated auctions can allow participants to observe competitors' bidding strategies and potentially identify departures from coordinated behaviour. UK government analysis of bid-rigging risks similarly identifies concentrated markets, repeated participation, stable market positions, and standardised products as factors capable of facilitating coordination.

However, similar prices or parallel bidding do not automatically establish unlawful collusion. Competition authorities normally require evidence demonstrating an agreement, concerted practice, information exchange, or other legally relevant coordination.

4. Competition-Law Framework

In the United Kingdom, Chapter I of the Competition Act 1998 prohibits agreements and concerted practices that have the object or effect of preventing, restricting, or distorting competition within the United Kingdom. Comparable conduct affecting EU trade may fall within Article 101 TFEU where EU law applies.

Electricity-market regulators therefore need surveillance systems capable of identifying abnormal bidding patterns, strategic capacity withholding, coordinated price movements, unusual communications, and repeated bid rotation.

Auction design can also reduce risk through anonymous bidding, appropriate disclosure rules, effective monitoring, penalties, independent market surveillance, and restrictions on exchanging commercially sensitive information.

5. Case Law

Nexans France SAS and Another v London Array Ltd and Others [2026] EWCA Civ 887

Facts: The proceedings arose from the European Commission's findings concerning a worldwide high-voltage power-cable cartel. Cable suppliers had allocated projects and exchanged commercially sensitive information. In relation to the London Array wind-farm project, the evidence included contacts concerning the price levels to be used in competing bids.

Legal Issue: Among the issues before the Court of Appeal was the legal effect of the Commission's cartel findings and allegations concerning collusive bidding connected with the London Array tender.

Judgment: The Court recognised that relevant findings in the Commission decision concerning Nexans were binding on the Competition Appeal Tribunal. The underlying decision established that Nexans participated in cartel conduct extending to project allocation and bid coordination.

Legal Principle/Ratio Decidendi: Competitors who secretly coordinate tender prices, allocate projects, or structure supporting bids can infringe competition law even though the procurement process outwardly appears competitive.

Significance: The case is particularly relevant to electricity-sector auctions because the cartel concerned high-voltage electricity infrastructure, demonstrating how coordinated bidding can directly distort energy-related procurement.

National Grid Electricity Transmission Plc v ABB Ltd and Others

Facts: National Grid pursued damages arising from the European Commission's power-cables cartel decision. The cartel involved allocation of projects, manipulation of tenders, supporting bids, exchange of confidential information, and mechanisms designed to prevent genuine price competition.

Legal Issue: Whether losses allegedly suffered through cartelised electricity-infrastructure procurement could support private competition-law damages claims.

Judgment: The litigation proceeded on the basis of the Commission's established cartel infringement and addressed consequences flowing from the anti-competitive conduct.

Legal Principle/Ratio Decidendi: Competition-law infringements involving bid manipulation can expose participating undertakings not only to regulatory penalties but also to private damages liability.

Significance: The case illustrates the financial and legal consequences of collusion in electricity-related procurement and reinforces the need for effective auction monitoring.

6. Conclusion

Collusion threatens the fundamental purpose of electricity auctions: competitive and transparent price discovery. Effective regulation therefore requires strong competition law, market surveillance, carefully designed auction rules, controls on sensitive information exchange, and meaningful sanctions. Preventing collusion ultimately protects consumers, infrastructure investors, and the integrity of electricity markets.