Hydropower and environmental impacts

Hydropower's overall environmental impact is limited to the water system.

The construction of hydropower alters the water system and its natural conditions. Hydropower production and regulation change the range and rhythm of the water level and flow rate. Hydropower dams and the use of power plants can hinder the migration of fish.These changes affect the local flora and fauna as well as recreational use of rivers and lakes.

When planning for new plants or upgrades on existing ones, the mitigating of environmental impacts is always a part of the equation. Utilities in Finland and Sweden take an active part in the research and development aiming to reduce local environmental impact.

Actions to moderate the environmental impact

Hydropower companies are obliged to compensate the environmental imact of hydropower production in regulated rivers. Fortum strives to reduce the impact on fishing by planting fish, restoring habitats and mitigating fish migration.
Furthermore, we  go beyond our legal obligations to reduce the environmental impacts of hydropower production through our involvement in voluntary environmental projects.

We cooperate with municipalities, environmental organisations and research institutes in many research projects to study the mitigation of environmental impacts, and we have funded dozens of projects studying the possibilities to improve the habitats of migratory fish and shellfish.


Fortum and other power companies with hydropower operations on major regulated rivers stock fish because it is considered the best way to offset the adverse impacts on the fishing industry. Every year, we plant about 700,000 salmon smolt in the Gulf of Bothnia in Finland and Sweden. Whitefish, zander and lake trout, for example, are planted in the rivers and regulated lakes where hydropower is produced. We have our own fish farms Finland and Sweden.

In Sweden, trap and transport is used in Klarälven with good results.In Finland, a similar pilot has started at Montta in Oulunjoki. In this very effective method migrating fish are trapped downstream and transported upriver to ensure natural breeding.
We continuously develop fisheries mitigation in cooperation with authorities, local fishermen and other stakeholders. We also take part in several mitigation projects and research on migrating fish. Various kinds of fish ways are studied: These can be fish ladders or bio-channels to help the natural migration of aquatic organisms. However, fish ways are far from being a universal solution to migratory fish issues, because research shows that they are often inefficient and not the optimal way to support the migrating fish spieces.

Local cooperation

We collaborate with local residents and municipalities, research institutes and environmental authorities in environmental restoration efforts and in the promotion of recreational use of water systems. The aim is to continuously develop the regulation of the watercourses so that the needs of hydropower production align with the needs of other water purposes. Recreational use has been improved by building boat moorage and launch ramps.

We have funded some of the fish projects in Sweden with revenue from Bra Miljöval-labelled electricity, while some of the proceeds from Ekoenergy-labelled electricity in Finland have been allocated to Fortum and The Finnish Association for Nature Conservation’s joint fund for use in the Vuoksi restoration project. We spent about EUR 745,000 in Finland and Sweden in 2015 on voluntary projects to mitigate and study the environmental impacts of hydropower production.