In 1923 Bergenshalvøens Kommunale Kraftselskap (BKK) expropriated large areas for power plants and development of hydropower started soon afterwards. Dale power station with the two first aggregates, each of 14 MW was put into operation on 17 November 1927. In the supply reservoir in Storefossen 5152 cubic metres of concrete were cast, and a modern and well-equipped power station was built.
Water discharge at the outlet of the Ekso into Eidsfjord was halved after the big hydropower development in the mountainous area between Modalen and Eksingedalen and further southward toward Evanger in the 1960s, 70s and 80s. In an attempt to amend the changed environmental conditions in the waterway the developer built 35 small dams in the river.
If you enter the farmyard at Rekve, some kilometres from Bulken, where the road departs to Giljarhus, you no longer meet “the miller”, Knut Hernes, in his old rural mill. But some years ago he would wish you welcome, friendly and hospitable, and show you around his mill, which had been his workplace for a generation. As light-footed as a youth he climbed in steep ladders high up into the waterfall, to let the water down on to the waterwheel.
Today Tyssedal appears like a classical industrial community, a picture of modern Norway from the turn of the former century until today. A/S Tyssefaldene was established in 1906, and on 1 May 1908 Tyssedal power station was put into operation. The work on the first stage of the facility was completed in a short time, with a work force of 500 men. They built water tunnels, regulation reservoirs, power station, penstocks, harbour, cableways, office buildings, houses and 6 km of power lines in the wild mountains above Odda to provide the new melting plant with power.
The 28th November 1914 was a day to remember for the Os inhabitants. This was the day they could turn the switch on the wall and have electric light in their houses. It was like opening the door on the future when the power station at Gåssand was put into operation.