The ACER Regulation grants ACER the authority to make individual decisions and establishes a Board of Appeal to handle appeals against specific decisions, outlined in Article 2(d). These include decisions related to:

• requests for information;
• approval of methodologies;
• terms and conditions;
• infrastructure; and
• some aspects of wholesale market integrity and transparency.

Any natural or legal person may appeal an ACER decision that is addressed to them or is of direct and individual concern to them.

The Board of Appeal operates as an independent body to address complaints lodged against ACER decisions. It examines whether the appeal is valid and can either confirm ACER’s decision or remit the case back to the competent ACER body for further action. 

Decisions taken by the Board of Appeal may as well be appealed before the Court of Justice of the European Union.

The Board of Appeal is part of ACER but at the same time independent from its administrative and regulatory structure. It is essential that members and alternates act independently and in the public interest.

The Board of Appeal is composed by six members and six alternates for a mandate of 5 years (renewable once).

Members and alternates are selected among current or former senior staff of the national regulatory authorities (NRAs), competition authorities or other national or EU institutions with relevant experience in the energy sector.​

The Board designates its Chair and Vice-Chair from among its members. The Chair is responsible for presiding and allocating appeal proceedings, while the Vice-Chair steps in for the Chair in case of unavailability.

To ensure the Board of Appeal operates smoothly and efficiently, a Registry has been established. The Registry supports the Board by managing the appeal process, handling correspondence and maintaining case files.

For more information on the Registry’s responsibilities, please refer to the Instructions to the Registrar.

For questions on the appeal procedure, you can contact the Registry via email at:

European Union Agency for the Cooperation of Energy Regulators
Trg republike 3
1000 Ljubljana
Slovenia

A word from Volker on his appointment as ACER Director ad interim (from 16 October 2025):

“I am honoured to be entrusted with leading ACER through this interim period from 16 October 2025 until the new Director is recruited. My main goal in the coming months is to ensure that the Agency continues to deliver on its mandate so that this transition is a time of consolidation - steadying the ship and preparing a solid foundation for the future.”

 - Volker Zuleger ​-

ACER is managed and represented by its Director. 

The Director’s term of office is five years. It may be prolonged by the Administrative Board once only, for a further five years.

Mr Volker Zuleger was appointed Director ad interim of ACER, following a decision by the Agency’s Administrative Board on 12 September. He took over as Director ad interim from 16 October 2025, ensuring the continuity of the service and the proper running of the Agency. He succeeds Mr Christian Zinglersen, who vacated the ACER Director post on 15 October to take up a new position elsewhere.

The Director represents the Agency vis-à-vis external stakeholders and ensures its internal functioning.

He adopts and publishes the official acts (opinions, recommendations and decisions), receiving a favourable opinion from the Board of Regulators.

He is responsible for drafting the annual work programme of the Agency and implementing it under the guidance of the Board of Regulators and the administrative control of the Administrative Board. The Director also draws up a preliminary draft budget and implements the Agency's approved budget. ​

Download high resolution photos of the ACER Director ad interim, Volker Zuleger:

• Official portrait
• Official portrait with ACER logo

Download Mr Zuleger's bio.

​You can contact Mr. Zuleger at:

The Annual Work programme contains ACER's multi-annual outlook, priorities and strategies. 

It is prepared by the Director and adopted by the Administrative Board.

​Before its adoption, the Administrative Board consults the European Commission and must receive a favourable opinion from the Board of Regulators on the ​​regulatory outline.
 

After the adoption, the Administrative Board transmits the Work programme to the European Parliament, the Council of the European Union and the Commission. 

The Work pr​​ogramme is then made public.​

​Have a look at the latest edition:

Every year ACER produces a Consolidated Annual Activity Report (CAAR) describing the activities performed and the objectives achieved during the year, as indicated in the Wo​rk Programme.

​Have a look at the latest edition:​

This section outlines why we in ACER collect energy data (our legal mandate), what energy data we collect, how we do it (data reporting) and how we ensure high data quality (through rigorous checking procedures) and confidentiality.

Two key features distinguish ACER from other energy data sources: 

1. our legal standing as an EU Agency; and 
2. our mandate in monitoring and assessing trading activities and in building trust in the integrity of EU energy markets.

REMIT is the EU-wide framework that protects wholesale energy markets from abuse, ensuring open and fair competition. Under the REMIT Regulation, ACER is mandated to collect data to monitor and assess trading activities on wholesale energy markets across the EU.

This EU-wide oversight of every trade in energy wholesale markets is unique to ACER. Working closely with national regulatory authorities (NRAs), we detect potential market abuse (such as insider trading and market manipulation). This supports market integrity, transparency and fair price formation.

Beyond its REMIT mandate, ACER also collects other data on wholesale and retail energy markets (e.g. under the electricity Capacity Allocation and Congestion Management (CACM) Regulation) to support its broader monitoring.

ACER and national regulatory authorities (NRAs) work closely together to protect energy markets from abuse. Increased transparency and monitoring build confidence that energy markets work well for EU businesses and citizens and that prices are determined in a fair way.

The rules for reporting energy market data to ACER are set out in the REMIT Implementing Regulation. Following the 2024 revision of REMIT, the Implementing Regulation has been updated in 2026 to include:

• new quarterly ‘exposure’ reporting, which requires market participants to report their trading positions (i.e. showing how exposed they are to future energy price movements over the next 18 months);
• new reporting elements for algorithmic trading and Direct Electronic Access (DEA);
• a clarified definition of obligations for ‘organised market places’ (OMPs) and other reporting parties; 
• extended reporting obligations for Liquified Natural Gas (LNG) and hydrogen transactions; and
• the introduction of ‘periodic data reporting’ (e.g. for balancing processes).

Based on these rules, ACER sets the procedures, standards and electronic formats (including reporting manuals such as the Transaction Reporting User Manual) that market participants must follow when submitting data. This centralised and structured system supports consistent data collection and effective market monitoring.

A full list of relevant documents is available on the REMIT Documents page.

To fulfil its mandate, ACER collects several types of data, including: 

• Transaction data: Records of trades and orders to trade relating to wholesale energy products, either traded on 'organised market places' (OMPs) or bilaterally. The wholesale energy product definition encompasses supply, transportation capacity allocation and storage of electricity, natural gas and hydrogen. This includes information on product type, quantity, price, delivery date, counterparty and beneficiary.
• LNG market data: Information about LNG transactions, used for both market monitoring activities and related ACER’s functions (including publication of its daily LNG price assessment and benchmark).
• Inside information: Market-sensitive information that must be publicly disclosed under REMIT, so that all market participants receive it transparently and at the same time. This concerns events that may affect wholesale energy prices (such as planned outages, unavailability, reduced capacity, maintenance delays or other events affecting production, storage or transmission). 
• Fundamental data: Information about energy assets, such as capacity and use of facilities for the production and storage of electricity, gas, LNG and hydrogen, including storage levels, consumption, transmission and generation outputs, as well as planned or unplanned outages.

ACER may request additional information or clarifications from market participants and reporting parties if the data submitted is incomplete or unclear. Reporting parties are responsible for submitting complete, accurate and timely data in line with the legal requirements and reporting arrangements.