Uppsala University has developed a directly driven generator for tidal/instream applications. The turbine in operation is a vertical axis turbine with five blades (could be three/four bladed) and a radius of ca 3m and a height of ca 3.5m. On its tripod the turbine reaches 4m above the river bed. Rotation speed: 15 (max 20) rpm at velocities of 2 m/s.
In the municipality of Söderfors, in the river Dal, 50 km north of Uppsala. The turbine is placed in a tributary part of the river, at 7m depth, and 200m downstream a hydropower dam. This enables experimental approaches including the possibility of controlling and changing velocity. The turbine is connected to a measuring station by a feeding cable located on the shore, 50m away. The facility is prepared for grid connection.
Early discussions in 2011-2012 with regional authorities resulted in the decision that the project, due to its small scale and only including one turbine, would be considered as a “small project”. Thus it would not need a formal permit, only consent from the regional authority, the county of Uppsala. A small project description was produced and consultations were held with a limited number of stakeholder (e.g. the local municipality, land and fishing right holders, and the utility company Vattenfall, owner of the nearby and upstream hydropower station). The current consent became affective in 2013, when the turbine was launched, and lasts for five years. A new consent will be applied for during 2018. The consent was conditioned with fish studies, mainly with focus on Salmonidae.
Although the project was not considered to cause environmental problems, by authorities or other stakeholders, Uppsala University had early plans of performing environmental studies, especially concerning eventual effect of the rotating turbine on fish.
No long term environmental monitoring was required by consenting authority, partly because the part of the river is regulated, the above hydropower station and absence of fish (Salmonidae) migration. However, effect studies, scuh as turbine fish interactions, was required. In 2015 Uppsala University performed test fishing in order to establish fish species assemblage in the waters. In 2017 the research group at Uppsala University, together with researchers from Chalmers University of Technology and in cooperation with the Swedish University of Agricultural Sciences (SLU), started to plan a number of fish-turbine interaction studies. In September 2017 the first study was initiated, release of salmons nearby the turbine in order to study behaviour – turbine passes, avoidance, deterrence. Observations are recorded with the help of a sonar system. The project has ethical and other necessary approvals for this study. In 2018 a laboratory study is planned at nearby fishery, at Älvkarleby, operated by SLU. In a small scale indoor brook aquarium two model turbines (one vertical axis and one horizontal axis) will be used for similar studies on Salmonidae smolt. Ethical and other necessary approvals is currently applied for.