Hydropower is the most important form of renewable energy in the Nordic countries.

It is virtually emissions-free and thus a key asset in mitigating climate change. Hydropower is reliable and flexible, so it plays an important role in balancing the increasing amount of intermittent renewable energy - such as solar and wind - in the system.

Hydropower plants regulate the water levels in lakes and reservoirs, storing water so that electricity production can be matched with the demand during peak hours. Hydropower is needed to keep the electricity system in balance and the grid technically well-functioning as well as to bring stability to prices.

Hydropower accounts for about one third of Fortum’s annual power production. 



The production of hydropower is based on the natural cycle of water. Hydropower plants utilise the difference in height between the dammed water and the water’s outflow. The dammed water is released through the power plant to the outflow. The energy harnessed from the water flow rotates a turbine that drives a generator. The generator converts the water’s energy into electricity. The same water can then be utilised again in the next plant downstream.

Fortum’s hydropower production in Finland and Sweden

In 2016, Fortum generated 20.7 terawatt-hours (TWh) of hydropower in the Nordic countries. Hydropower accounted for 28% of our total electricity production. The share fluctuates every year depending on the hydrological situation.

Our hydropower production capacity totals 4650 megawatts (MW). A significant share of the capacity is generated by 127 hydropower plants in central Sweden. The biggest plants are on the Ljusnan, Indalsälven and Dalälven rivers.

In Finland , we fully own and operate 13 hydropower plants on the Oulujoki and Vuoksi waterways, and co-own and operate an additional 20 hydropower plants through our stake in Kemijoki Oy.