National regulators and the future of electricity transmission networks: new CEER report reveals gaps and inconsistencies in the oversight on network investments

With the publication of its new report, “NRA Oversight on Electricity Transmission Grid Development and Investment“ (C25-RBL-08-03), the Council of European Energy Regulators (CEER) puts the spotlight on the role of national regulatory authorities (NRAs) in the development of electricity transmission networks in Europe. The document, prepared by CEER’s Regulatory Benchmarking and Law Working Group, is based on an in-depth survey of 19 regulators and outlines both the progress and systemic weaknesses in the oversight of network investments that are critical to the success of the European green transition.

Context and purpose

Europe’s energy transformation depends on the rapid and efficient development of electricity transmission infrastructure to integrate growing shares of renewable energy and ensure system reliability. NRAs play a key role in this process by supervising transmission investments, ensuring cost-effectiveness, and ensuring consistency with EU policy objectives.

The report analyzes the role of regulators in the three main stages of network planning:

1. Planning and approval of national network development plans (NDPs) and assessment processes;
2. Implementation of investments and instruments to ensure their implementation in accordance with the plans;
3. Monitoring and control of costs – the extent to which regulators monitor progress, cost efficiency, and their impact on tariffs.

The study provides information on the distribution of responsibilities between NRAs, transmission system operators (TSOs), and public authorities, identifying regulatory gaps, best practices, and key challenges in managing transmission network development.

Key findings

The report highlights the fragmented regulatory environment in Europe. Although EU legislation provides a common framework, national implementation and the competences of NRAs vary considerably:

• Content of NRAs: All countries include cost estimates in their NRAs, but few provide detailed explanations of cost evolution or tariff impacts. The scope and depth of cost-benefit and risk analyses vary considerably, and some key investment topics remain optional or absent.
• Fragmented regulatory environment: The report finds significant differences between Member States in how network investments are assessed, approved, and monitored. Although European legislation (in particular Article 51 of Directive (EU) 2019/944) sets the framework, national transposition remains uneven – only 14 out of 19 countries have fully implemented its requirements, often regardless of the unbundling model (OU/ITO/ISO).
• Insufficient cost transparency: All analyzed national plans include forecast values, but only 6 out of 19 regulators indicate that sufficient explanation is provided on the dynamics of costs over time, and only 7 out of 19 indicate that the tariff impact on consumers has been assessed. Detailed CAPEX/OPEX estimates are published in only a few countries (e.g., Spain, France), while in others (Belgium, Luxembourg) the information is limited or aggregated.
• Limited regulatory powers: About half of NRAs do not have the power to unilaterally change network development plans, even when they identify gaps. In most countries, approved plans are legally binding on the transmission system operator (TSO), but control over actual implementation and costs is often weaker than control in the planning phase.
• Uneven access to resources and expertise: There are large differences between NRAs in terms of staffing and technical expertise, ranging from more than 10 full-time experts in Portugal and Germany to less than one expert in some Eastern European regulators. Most NRAs rely on data and models provided by the operators themselves, leading to information asymmetry and dependence on TSO analysis. Recurring obstacles include limited resources, data asymmetry between NRAs and TSOs, and the difficulty of planning in a rapidly evolving energy system with tight deadlines.
• Limited monitoring and reporting: Although most regulators monitor project progress, only two countries systematically assess the impact on end-user bills. In 11 countries, there is no obligation to publicly disclose updated investment costs.

Key challenges

CEER has identified several systemic problems:

• Limited resources and capacity of NRAs vis-à-vis operators;
• Information asymmetry and lack of standardized methodologies for cost and risk analysis;
• Excessively high frequency of plan updates (every two years), which requires disproportionate administrative resources;
• Insufficient integration of new topics – digitalisation, climate resilience, renewal and cybersecurity.

Examples and good practices

• Germany (BNetzA) applies the most detailed technical verification of network projects – simulations of 8,760 hours of load flows per scenario for each year and each project.
• Spain (CNMC) requires an explicit Cost-Benefit Analysis (CBA) by law and publishes complete data on investment costs.
• France (CRE) combines CBA and environmental criteria, including compatibility with climate targets, when assessing RTE’s annual investment programs.
• Portugal (ERSE) develops incentives for technical efficiency and power quality linked to the implementation of the NDP.

Recommendations

The report aims to assist European and national stakeholders in identifying areas where regulatory practices can be strengthened to increase transparency, accountability, and efficiency in electricity network development. It calls for improved access to data and NRO modeling capacity, clearer guidance on NDP content requirements, and more balanced powers at all stages of electricity network development. These key measures would help to ensure the efficiency of investments in the transmission network and compliance with Europe’s long-term energy and climate goals:

1. Strengthening the powers of regulators – including the right to amend plans where gaps are identified and stricter enforcement mechanisms in the event of non-compliance with investments.
2. Increase the transparency of TSOs – more detailed explanations of the costs, benefits, and tariff implications of projects at an early stage.
3. Share best practices between NRAs through CEER and ACER to create more uniform supervisory standards.
4. Closer coordination between sectors – joint planning of electricity, gas, and hydrogen through integrated scenarios.
5. Investment in the analytical capacity of regulators – development of internal models for technical and economic analysis.

Regulatory oversight as a guarantee for an effective transition

The report clearly shows that regulatory consistency is a prerequisite for investment security in the new energy paradigm. Uneven enforcement of rules and dependence on operator data risk delaying the implementation of key projects, especially those related to cross-border connectivity and RES integration.

CEER emphasizes that strengthening the analytical and institutional capacity of regulators is a strategic investment, not an administrative expense. Only with equal access to information and tools can oversight ensure that every euro invested in the grid actually serves the goals of the green transition and European consumers.