These nine power stations are; Suldal I, Suldal II, Røldal, Novle, Kvanndal, Svandalsflona, Middyr, Vasstøl and Midtlæger.
The fall rights in Røldal and Suldalsdraget were bought by Hydro already in the 1950s, with the aim to acquire power for a new aluminum plant at Karmøy. The hydropower plants Suldal I, Røldal, Suldal II, Kvanndal and Novle were expanded one by one and completed in 1968. Later, the power stations Svandalsflona, Middyr, Vasstøl and Midtlæger were added.
At the same time as the main development of the power plants took place, Hydro's aluminum plant on Karmøy was built. Thanks to new technology, it was now possible to transport the power on its own lines, and thus the hydropower plants in Røldal and Suldal could become the main suppliers of power to the aluminum production on Karmøy.
The power plants in the “Western watercourse” utilize a fall from the highest reservoir Nupstjørn 1302 meters above sea level (masl) down to Suldalsvatn 68 masl. The power stations are located one after the other in the watercourse, so energy can be used several times. The water from Nupstjørn, for example, flows through five power stations before reaching Suldalsvatnet. In the "Eastern watercourse" one utilizes the fall from Holmevatn 1058 masl and down to Suldalsvatn 68 masl.
Here, the water passes through two power stations, where the highest utilized single case is about 560. The plant consists of 17 regulation reservoirs and 21 stream intakes. The main reservoirs are Votna, Valldalen, Røldalsvatn, Sandvatn and Holmevatn.
Lyse Kraft DA
The Røldal-Suldal facilities are owned by the hydropower company Lyse Kraft DA. Hydro and Lyse have merged parts of hydropower production in southern Norway into a joint hydropower company, Lyse Kraft DA, which is Norway's third largest hydropower player.
The transaction was completed on 31 December 2020, and you can read more about the hydropower agreement here.
Lyse Kraft DA has a normal annual power production capacity of 9.5 TWh, of which Hydro owns 25.6 per cent and Lyse 74.4 per cent. As part of the agreement, Hydro will remain the operator of RSK and will now also take over the operatorship of Lyses' hitherto wholly owned hydropower plant. Lyse will be responsible for marketing activities and water disposal.
As a result of the agreement, Hydro is Norway's third largest operator of renewable power production, with a total production of 13.6 TWh in a normal year. Adjusted for ownership, Hydro's annual power production is 9.4 TWh in a normal year.