Magnus Hall, chief executive of Swedish utility and renewables giant Vattenfall, has resigned after six years at the helm.

Hall will leave before the end of January 2021, making him at least the third high-profile CEO to resign in a month within Europe's clean energy sector, following similar shifts at Ørsted and Siemens Gamesa.

Hall told an analyst conference call that he was leaving for personal reasons after six “quite intensive” years and is now looking to slow down. During his tenure, he instigated Vattenfall's goal of enabling "fossil-free living" within a generation. By 2023, the state-owned company expects to have 7 gigawatts of wind and solar in operation and a pipeline of 3 to 5 gigawatts in development.

The announcement came in tandem with the release of a disappointing set of quarterly results, with lower power prices and depressed generation across Vattenfall's fleet taking a toll on the company and requiring substantial asset write-downs.

Net sales for April to June fell 10 percent to SEK 31.3 billion ($3.5 billion) compared to the same period last year. Vattenfall swallowed a quarterly loss of SEK 7 billion compared to a profit of SEK 2.8 billion at this time in 2019.

Vattenfall wrote down the value of its Moorburg coal power plant in Germany by SEK 9.1 billion ($1.02 billion). The 1.6-gigawatt facility in Hamburg is the company’s last condensing coal power plant in continental Europe. It also has 650 megawatts of district heating output.

Hall said Vattenfall doesn't know what the future holds for Moorburg. “We are looking at the different options. One option is to bid into Germany’s [capacity] auctions, one option is to sell it, another is to convert it to other fuels." The company could also continue running it as usual, he said.

Vattenfall also wrote down the value of some of its wind assets by SEK 1.5 billion, mainly onshore projects in Sweden and Denmark, as a result of cheaper power prices and lower values for the renewable energy certificates the projects generate.

The projects in question tend to be older assets with a much higher levelized cost of electricity, said CFO Anna Borg.

Electricity futures prices in 2020 are down more than 30 percent in the Nordics and 20 percent in continental Europe compared to last year, according to Vattenfall. The certificate-based subsidy program in Sweden is market-driven, so as prices for power have fallen, so too has the value of the certificates.

Borg said Vattenfall considers its adjustment for power pricing to be a long-term one.

EDP's CEO "suspended" from duties

Europe's clean-energy sector has seen considerable management upheaval in recent weeks. Last month Henrik Poulsen announced he will leave global offshore wind leader Ørsted, while a few days later wind turbine manufacturer Siemens Gamesa replaced Markus Tacke with Andreas Nauen as it looks to bolster its onshore business.

Elsewhere, a lengthy corruption investigation in Portugal saw the CEOs of EDP and EDPR removed by a magistrate. António Mexia and João Manso Neto remain suspended from their duties but have not been formally charged. The case was instigated in 2012 and also involves a former Portuguese energy minister, Artur Trindade. It centers around allegations that the companies were awarded hydropower concessions unfairly that ultimately benefited the company to the tune of €1.2 billion.

EDP denies any wrongdoing and said in a statement that the allegations “lack substance.”