Sima Hydroelectric Power Station


Sima power plant is a storage power plant in western Norway in the municipality of Eidfjord. It is by the power plant Kvilldal the second largest power station in Norway and one of the largest hydroelectric power plants in Europe.


The power plant is located at the inner end of the Simadalsfjords, a tributary of the Eidfjords, which in turn is the nordöstlichte foothills of the Hardangerfjord. There are some surface facilities are only to be seen. The largest part is built as underground power station 700 meters into the rock of the northern flank of the Simatals ( norw Simadalen ). The outlet of the power station opens below the water line of a steep cliff directly into the fjord.

In the high-altitude on a about 600 meters on a terrace above the Simadalsfjord homestead Kjeåsen are also caverns in other parts of the plant such as gate valves, water castle and maintenance access to the penstocks. To this end, the once very remote farmstead has been developed by a 2.5 km long access tunnel.


The history of the Sima power plant dates back to the year 1917, when the Osa Fossekompani A / S began in the municipality of Ulvik with the construction of a hydroelectric plant in Osa. The work was, however, set unfinished after eight years.

During the Second World War, the project of the German occupation, was planning an aluminum smelter in Osa was taken up again, but again abandoned after a short time.

In 1962 Statskraftverkene started with a new plan, which should include a much larger area. 1968, the planning application was submitted in 1973 by the Norwegian Storting (parliament ) approved in reduced form.

After seven years of construction with up to 1,200 workers employed at the same time (1977 ) the Sima power plant was put into operation in 1980.

Catchment area

Sima power plant draws its water from two geographically separate drive areas. Both are at very low proposal and snowy western edge of the Hardangervidda and refer the west, south and southeast of the glacier Hardangerjøkul running melt water with a. The water in these basins drives two separate parts of the system, so you just put two power plants requires that they are housed in a common turbine hall: Lang- Sima and Sy - Sima.

Lang- Sima

Lang- Sima gets its water alternatively from the two northern reservoirs Langavatnet, from which the name of this plant part derived, and Rundavatnet on a common 8 km long pressure tunnel. This leads to the shut-off valve at Kjeåsen and has a cross sectional area of ​​30 square meters.

With the help of several transfer tunnel in Langavatnet the upper part of the originally Simatal and the river Austdøla flowing water is collected. This includes flowing down from the west side of the Hardangerjøkul meltwater.

In Rundavatnet the water of the lower part of the Austdøla and through a tunnel from the 6 km north-west lake Skrulsvatnet the river water Norddøla is collected. This also includes the meltwater some snowfields a ( Osaskavlen ).

Sy - Sima

Sy - Sima is mainly fed from the river system of the Bjoreio whose water is diverted into the reservoir Sysenvatnet. Thus, the catchment area extends over 20 km far southeast of the lake into the Hardangervidda. The reservoir, from whose name the name of this part of the plant is derived, is located in a northern tributary of the Bjoreio and even takes numerous meltwater runs of the northern Hardangerjøkuls on. The dam consists of 3.6 million cubic meters of rubble, the length of its dam is 1100 meters. He is one of the largest in Norway. He is right on the leading of Eidfjord over Hardangervidda to Geilo National Highway 7 ( Riksvei 7).

From Sysenvatnet the water is passed through a 14 km long tunnel with a cross sectional area of ​​35 square meters to the north-west at the top of Simatals reservoir Rembesdalsvatnet, which also is fed by meltwater from the eastern glacier tongue Rembesdalskåka and some other from the north coming streams.

From Rembesdalsvatnet the water flows through a 7 km long pressure tunnel with a cross sectional area of ​​52 square meters to the moated castle and the gate valve at Kjeåsen. The balance shaft of the water castle serves to initiate the flowing down from the upper lake Kjeåsvatnet watercourse asana.

Power station

From the slides at Kjeåsen perform two 850 -meter-long steel-clad pressure tunnels with a gradient of 1:1 to the power plant down. The inner diameter of the tube for long - Sima decreases from top to bottom, from 3.4 to 2.75 meters, the. For Sy - Sima from 3.9 to 3.0 meters The steel shell has a thickness of up to 78 or 68 millimeters, there were 7500 tonnes of steel installed for it. At the bottom of the two tubes divide into two branches, each of which serves as an inlet to one of the four turbines.

The machine hall of the power station is located in a 200 meters long, 20 meters wide and 40 meters high cavern. It is located only a few meters above sea level and has a 700 meter long access tunnel from the bottom of Simatals.

The gross head of Lang- Sima, depending on the active inlet 1152 meters from Langvatnet or 1034 meters from Rundavatnet. For two Pelton turbines with vertical shaft position and five nozzles are driven. The two higher than the turbines generators provide a capacity of 250 megawatts.

When Sy - Sima also two Pelton turbines with vertical shaft position and five nozzles are driven with a drop height of 855 meters. The arranged above generators provide 310 megawatts each.

The power plant has an annual working capacity of a total of 2728 GWh, of which provide Sy - Sima 1640 GWh and 1088 GWh long - Sima.

The control and monitoring of the power plant is carried out by the operations center in Sauda about 100 kilometers away.