An additional generator will be installed at Grunnåi Power Plant, which will increase its annual production by 20 per cent. This work will be carried out in the period from November 2018 to September 2019.
Grunnåi Power Plant was completed in 2006, and despite its small intake dam, can virtually be regarded as a run-of-the-river power plant. With large amounts of precipitation and during snow melting, a lot of water will flow past the station.
Utilising flood waters
To reduce the loss of flood waters, the owners, consisting of local landowners, Vest-Telemark Kraftlag and Skagerak Kraft, have decided to expand the station by one additional generator. There is plenty of space inside the station for another generator, and the supply tunnel also has sufficient capacity to supply an additional generator with water.
Skansa is the building contractor for the project, and will start setting up inside the station in mid-November 2018. Aside from some construction traffic, the work will not affect the surrounding area to any significant degree.
Andritz Hydro is the supplier of the generator, transformer and electrical work and will start up in March/April when Skansa have finished their construction work.
Construction to begin November 2018
The power station is located 500 metres inside Mælefjell mountain, and blasting will take place from December to February. Since this work will occur deep inside the mountain, it will not normally be noticeable in the surrounding area. Sensors will be installed to measure tremors caused by the work.
There will be some construction traffic in connection with the work. The blasted rock mass will be temporarily stored near the tunnel entrance to the power plant and will reduce the need for heavy transport on the road up to the plant. This road is private, and ordinary use of the road will be regulated with signage during the construction period.
Lowered water level
The Norwegian Water Resources and Energy Directorate (NVE) has granted Grunnåi kraftverk AS permission to lower the water level in the intake reservoir below the minimum regulated water level (LRV) at contour line 572, and to let the Grunnåi river flow freely through the bottom outlet in the period from 10 December 2018 to 1 April 2019.
Increase in annual production by 20 per cent
The power station will be out of operation from around Christmas until 1 April. On 1 September 2019, the refurbished power station will be put into full operation. The average annual production will then have increased by 11 GWh to 61 GWh. The development costs are estimated to be NOK 35 million.