Vattenfall has installed six floating islands in the Dalälven River downstream of the Älvkarleby hydropower station. The initiative is part of the company’s hydropower biodiversity programme and aims to create habitats that support breeding birds and aquatic species.
Hydropower is a key part of Sweden’s electricity mix and its fossil-free transition. However, regulated rivers are subject to fluctuating water levels, which can reduce biodiversity and damage near-shore ecosystems. Vattenfall is testing solutions to mitigate these effects while maintaining hydropower production.
“The floating islands follow the natural variation of the water surface and provide a stable platform for vegetation and wildlife,” said Henrik Viklands, Head of Vattenfall Hydropower’s Biodiversity Programme. “They offer nesting areas for birds and create favourable conditions for plankton, fish, and algae.”
Each artificial island measures about 15 square metres. The six units are linked to form a single 90-square-metre hexagonal structure. Designed and built at Vattenfall’s R&D laboratory in Älvkarleby, the islands are planted with species typical of local shore and aquatic environments.
“The project supports global sustainability goals and contributes to Vattenfall’s target of implementing its biodiversity plan by 2030,” said Choudhury Maidul, biologist at Vattenfall Research and Development.
Artificial regulation of water levels can cause erosion and loss of shallow-water habitats. Floating islands are being tested as a potential mitigation measure that enhances biodiversity without reducing energy output. This is the first time islands of this scale have been tested in Sweden, and the project will help identify effective design and construction methods for northern environments where ice cover, low temperatures, and short growing seasons pose challenges.
