Power waterfall, (in Norwegian Strømsfoss). Strømsfoss power station is a hydroelectric power plant in Halden watercourse in Aremark municipality in Østfold county. Production started in 1920 and the plant was modified in 1994. The work is a river plant. The total average annual production is 2.5 GWh and installed capacity is 0.5 MW. The plant has a Francis turbine and Kaplan turbine.