This week ACER, the pan-EU energy regulator, confirmed the appointment of its new permanent Director (click here). The new Director will succeed Volker Zuleger, a long-serving senior manager at ACER, who has been serving as an ad interim head since October 2025. He was appointed to the post after Christian Zinglersen stepped down as Director on 15 October 2025, around nine months into his second five-year term, to become Deputy Secretary General at the European Investment Bank (EIB) Group.
Most in the market had anticipated that Zuleger's (internal) appointment would remain temporary as an external candidate for the role was sought. ACER's Administrative Board selected the candidate following an "open recruitment process" and after receiving a favourable opinion from the ACER Board of Regulators, with the EU Parliament's Committee on Industry, Research and Energy (ITRE) holding a hearing with the candidate on 10 September as a further step in the process.
Appointed to the permanent Director role is Dr Christof Lessenich, a German national who has spent most of his career within the EU Commission in Brussels. He joined the Commission's DG Competition (DG COMP) in 2007, spending roughly 14 years there, including as Policy Assistant to the Director-General (2011 - 2016) and then as Head of Unit for State Aid in the energy sector (2016 - 2021), before moving to DG Energy (DG ENER) in June 2021. Dr Lessenich was appointed as Head of the Internal Energy Market Unit (ENER C3) at DG ENER, a role he has held for just over five years. In this role, he oversaw EU electricity and gas market policy.
Earlier in his career, Dr Lessenich practised law in the private sector at a major law firm. While it is not entirely clear what sort of policy direction the new head of ACER is likely to pursue (and the announcement itself is silent on the point), his focus on EU electricity and gas market functioning at the DG ENER augurs well for continuity on topics such as market integration. His many years at DG COMP might also play a role in informing his position on topics like state subsidies and market intervention although this remains to be seen.
A change in leadership at any regulator is usually accompanied by a shift in focus, potentially presenting new and emerging risks for firms in the process. While such change is unlikely to be rapid, firms active in EU wholesale energy markets should nonetheless remain cognisant of this development.
