Introduction

Wholesale electricity market transparency refers to legal and regulatory duties requiring market operators, generators, traders, transmission entities and regulators to disclose sufficient information about electricity prices, bids, available capacity, dispatch, congestion, outages and settlement outcomes. Transparency reduces information asymmetry, supports competition and assists regulators in detecting manipulation, discriminatory conduct and abuse of market power.

In South Africa, these obligations have become particularly important following the Electricity Regulation Amendment Act 38 of 2024, which commenced on 1 January 2025 and establishes the legislative basis for an open competitive electricity market.

Electricity Regulation Amendment Act and Market Transparency

The amended Electricity Regulation Act requires the electricity market operator to provide a transparent and non-discriminatory trading platform, approved by NERSA, through which power-market participants may trade electricity. The market operator must also develop a Market Code and Market Rules, including qualifying requirements for participants.

Transparency therefore extends beyond publishing prices. The regulatory framework may require disclosure or reporting concerning:

bids and offers submitted into the wholesale market;

scheduled and actual electricity generation;

transmission-network availability;

planned and unplanned outages;

congestion and network constraints;

electricity prices and settlement information;

balancing and ancillary-service transactions; and

conduct potentially indicating market manipulation.

Such information enables participants to understand market conditions while allowing NERSA to supervise market integrity.

SAWEM Market Surveillance

NERSA has established a Market Surveillance Unit (MSU) for oversight of the South African Wholesale Electricity Market (SAWEM). The MSU monitors trading activity, bidding behaviour, dispatch outcomes and settlement results and may investigate conduct indicating breaches of the Market Code or Market Rules. NERSA also identifies transparency and reporting as a core surveillance function, including publication of market assessments and surveillance reports.

Market transparency is therefore closely connected to enforcement. Access to reliable trading information allows the regulator to identify withholding of generation capacity, discriminatory network access, abnormal bidding patterns and other potentially abusive conduct.

Non-Discriminatory Network Information

Transparency also applies to transmission access. The amended legislation requires the transmitter to provide non-discriminatory access to the transmission power system.

Effective non-discrimination depends upon participants receiving reasonably equivalent information about available transmission capacity, connection restrictions, outages and congestion. Preferential access to commercially significant network information could distort competition and undermine confidence in wholesale trading.

Public Participation and Regulatory Disclosure

Electricity regulation also constitutes administrative action subject to constitutional principles of legality, accountability and procedural fairness. Where NERSA determines or approves tariffs, adequate information must be available to affected parties so that consultation and public participation are meaningful.

CASE LAW

1. Afriforum NPC v National Energy Regulator of South Africa [2025] ZAGPPHC 1176

Facts: AfriForum challenged NERSA's public-participation process relating to municipal electricity tariff approvals.

Legal Issue: Whether NERSA had provided sufficient information and a lawful opportunity for meaningful participation.

Judgment: The High Court declared NERSA's public-participation process invalid. It directed NERSA, among other things, to give municipalities timely notice of applicable bulk wholesale tariffs and to publish municipal tariff applications together with their cost-of-supply studies.

Legal Principle/Ratio: Regulatory participation must be supported by disclosure of material information necessary for affected persons to understand and respond to proposed electricity charges.

Significance: The judgment demonstrates that transparency in electricity regulation is a substantive requirement rather than merely publication of a final decision.

2. Casting, Forging and Machining Cluster of South Africa v NERSA [2022] ZAGPPHC 927

Facts: Industrial electricity consumers challenged NERSA's approval of City Power tariffs, arguing that the regulator had not properly considered cost-of-supply information.

Legal Issue: Whether a tariff determination made without adequate economic cost information was lawful and rational.

Judgment: The High Court found the tariff determination unlawful and invalid because NERSA had failed properly to consider relevant cost-of-supply information.

Legal Principle/Ratio: Material economic information must form part of a rational regulatory decision-making process.

Significance: The case reinforces the broader principle that transparent access to reliable market and cost information is essential for accountable electricity regulation.

Conclusion

Wholesale electricity market transparency is fundamental to South Africa's transition toward competitive electricity trading. Disclosure of prices, bids, capacity, congestion, dispatch and settlement information supports informed participation, non-discrimination and market surveillance. Combined with NERSA's oversight and administrative-law requirements, transparency provides an important safeguard against information asymmetry, market manipulation and arbitrary regulatory decision-making.