Fortum Launches 25 MW Floating Solar Farm on Lake Saimaa

In a significant step forward for renewable energy in the Nordics, Finnish energy giant Fortum has announced the launch of a pioneering 25 MW floating solar photovoltaic (PV) farm on Lake Saimaa, Finland’s largest lake. Set for full commissioning in the first quarter of 2026, this project is not only one of the largest of its kind in Northern Europe but also a showcase of innovative engineering designed to harness clean energy while coexisting with a sensitive natural environment.

A Landmark Project: The Floating solar farm on Finland’s Largest Lake

The new solar farm represents a major milestone in utilizing water surfaces for power generation, a crucial strategy in a country where land is a precious resource. Located on Lake Saimaa, within the Saimaa Ringed Seal National Park area, the project has been meticulously planned to minimize its environmental footprint.

Here are the key details of this ambitious installation:

• Capacity and Generation: With a capacity of 25 MW, the farm is expected to generate approximately 25 GWh of clean electricity annually. This is enough to power around 5,000 average Finnish households, making a tangible contribution to the region’s energy needs.
• Scale and Technology: The facility spans roughly 50 hectares and features approximately 60,000 high-efficiency bifacial solar panels. These panels are mounted on robust high-density polyethylene (HDPE) floating structures, which are securely anchored to the lakebed. The design is built to withstand the harsh Nordic climate, including ice formation during the winter months.
• Timeline and Investment: Construction began in late 2024, with a total investment from Fortum estimated between €25-30 million, supported by green energy grants from the European Union.

Environmental and Technical Advantages of the Floating solar farm

Floating solar, or ‘floatovoltaics’, offers several unique benefits over traditional ground-mounted systems, many of which are being leveraged by the Lake Saimaa project.

Enhanced Efficiency Through Natural Cooling for the Floating solar farm

One of the most significant advantages is the natural cooling effect provided by the water. The proximity to the lake keeps the solar panels 5-10°C cooler than their land-based counterparts. This seemingly small temperature difference can boost energy efficiency by a remarkable 10-15%, maximizing output from each panel. Early performance data from Fortum’s monitoring has already shown an uptime of 98% and a yield 12% higher than comparable ground-based systems.

A Symbiotic Relationship with the Ecosystem and the Floating solar farm

Fortum has placed a strong emphasis on ecological sustainability. The project is designed to protect local biodiversity, including the critically endangered Saimaa ringed seals. By shading the water, the panels help reduce algae growth, and extensive studies have indicated minimal disruption to water quality or local fish populations. Furthermore, by using the lake’s surface, the project avoids deforestation and land-use conflicts associated with large-scale ground installations.

Supporting Finland’s Carbon Neutrality Goals with the Floating solar farm

The electricity generated will be fed directly into Fortum’s grid, supporting Finland’s ambitious goal of achieving carbon neutrality by 2035. The solar farm’s output, which peaks during the long summer days, perfectly complements other renewable sources like wind and hydropower, contributing to a more stable and resilient energy system.

A Glimpse into the Future of Energy with the Floating solar farm

This 25 MW installation is not Fortum’s first venture into floating solar on Lake Saimaa; it builds upon the success of a 1 MW pilot project launched in 2022. The project’s scale has garnered international attention, with industry reports from Reuters and SolarPower Europe noting it as Europe’s fifth-largest floating PV project.

The global capacity of floating solar reached 13 GW by 2025, according to data from IRENA, and Finland is increasingly embracing this technology as a solution to land scarcity. For Fortum, the Lake Saimaa farm is a key part of its strategy to transition to a 100% renewable portfolio by 2040.

As this innovative project comes online, it stands as a powerful example of how technology can be harnessed to generate clean energy in harmony with nature.

For further details and ongoing updates, you can refer to official announcements on Fortum’s website and reports from the Finnish Energy Authority.