Juktan

History

When Juktan Power Station was opened in 1978, it had several unusual features. It used different lakes at different altitudes as water sources and the lakes were connected by tunnels and water pumps. It transferred water from one reservoir, Lake Storjuktan in Juktån, a tributary of the Ume Älv River, to another, Lake Storuman in the main Ume Älv River. From Storjuktan the water was pumped to a third reservoir, Lake Blaiksjön, at an elevation more than 210 metres higher. Upon power generation, the water was discharged to Storuman giving a net head (drop) of about 270 metres. The station thus utilised three reservoirs. Due to the difference in elevation of about 60 metres between the lakes Storjuktan and Storuman, the power consumption for pumping water from Storjuktan to Blaiksjön equalled the amount possible to generate between Blaiksjön and Storuman. However, the diversion of the Juktån River to the main river at a higher elevation than that of the natural outflow of the tributary also allowed the water to be used in three existing stations on the Ume Älv River. This yielded generation of an additional 140 GWh per year.

Construction

Construction work started in the spring of 1973 and was completed in the autumn of 1978. The work was dominated by the large amount of rock blasting, totalling an excavated volume of 1.8 million m3. The total amount of earth excavation and dam fill was 1.4 million m3.

Conversion to a pumped storage plant

To meet the increasing demand for new fossil-free electricity, Vattenfall is investigating the possibility of converting Juktan back into a pumped storage power plant.