Finnish court rules Fortum lacks permit for rapid flow regulation at Imatra hydro plant

A Finnish administrative court has upheld a regional authority’s decision that energy company Fortum does not hold the right to conduct short-term flow regulation at its Tainionkoski hydroelectric plant on the Vuoksi River in Imatra.

The Vaasa Administrative Court rejected Fortum’s appeal on Thursday, affirming the Regional State Administrative Agency’s earlier ruling that the company’s water permit does not include authorization for rapid, repeated adjustments to water discharge—known as short-term regulation. This practice, which can alter flow rates multiple times daily to match electricity demand and pricing, has been linked to adverse environmental impacts on the waterway and its recreational use.

Fortum has carried out short-term regulation at Tainionkoski since the 1970s but argued in its appeal that the practice was covered under its existing permit. The court found no explicit provision for such operations in the company’s water rights documentation. A 2021 study commissioned by the Finnish Environment Institute’s RiverGo project had previously concluded that the practice required a separate permit.

Katri Hämäläinen, Fortum’s environmental director, told national broadcaster Yle that the company is reviewing the ruling and declined further comment.

The Finnish Association for Nature Conservation welcomed the decision, calling it “simple and clear” in a statement. Environmental law expert Hannes Koljonen noted that “unauthorized activity does not become lawful simply because it has been done for decades.” The group questioned why the Centre for Economic Development, Transport and the Environment (ELY Centre), the oversight body for the plant, had not intervened earlier. It also suggested that similar unpermitted short-term regulation may be occurring at other hydroelectric facilities nationwide.