Regulators rule rapid water flow adjustments legal at Isohaara hydropower plant

A Finnish licensing authority has dismissed calls from environmental groups to halt short-term water flow regulation at the Isohaara hydropower plant on the Kemijoki River, ruling the practice compliant with existing permits, Yle reports.

The Regional State Administrative Agency (LVV) rejected an emergency application filed by the Finnish Association for Nature Conservation, its Lapland branch, and the Wild Salmon Association, which argued that the rapid adjustments—where water flow is sharply increased or decreased in short intervals—violated the plant’s operational permits.

In its decision, the LVV stated that short-term regulation was accounted for when the plant’s water management permits were originally issued. The agency cited prior rulings by the Water Court and the Supreme Administrative Court (1964–1992), which determined that daily fluctuations in water levels did not constitute “significant harmful changes to natural conditions” and that permit terms referred only to 24-hour average flow rates, not instantaneous variations.

PVO-Vesivoima Oy, the plant’s operator, welcomed the ruling. “The application claimed we were engaging in unpermitted short-term regulation. We’re satisfied that the LVV confirmed this is not the case,” said CEO Jani Pulli. The company argues that such regulation is necessary to stabilise the grid amid growing intermittent renewable energy from wind and solar, particularly during high-demand periods with low wind.

Environmental groups countered that the practice severely disrupts the river ecosystem and recreational use upstream of the plant. The Finnish Association for Nature Conservation announced plans to appeal the decision in administrative court, insisting the plant’s permits never explicitly covered short-term regulation.

“We interpret the water management permit differently than PVO and now the LVV,” said environmental law expert Hannes Koljonen. “In our view, short-term regulation was never applied for or approved.”

The dispute echoes a 2005 Supreme Administrative Court precedent requiring explicit permits for short-term regulation, including thorough impact assessments. In 2025, the LVV applied this ruling to revoke Fortum’s claimed right to short-term adjustments at its Tainionkoski plant, where permits lacked specific provisions for the practice.

PVO-Vesivoima stated it would monitor the appeal process but hoped for a resolution to focus on electricity production. Environmental groups maintain the rapid flow changes harm the Kemijoki River’s natural state and public accessibility.