Norsk Hydro has announced it will invest approximately NOK 850M over the next four years to upgrade the Rjukan hydropower system in Telemark, southeast Norway, modernizing the major hydroelectric facility to ensure long-term safe and stable power supplies.

The Rjukan power system comprises five power plants – Frøystul, Vemork, Såheim, Moflåt and Mæl – with a combined normal annual capacity of approximately 3TWh or about 30% of Hydro’s normal annual hydropower production.

The planned work will consist of upgrading the waterways, including building a new dam at Skarfoss, new control systems and power distribution, as well as rehabilitating generators and turbines.

“We need to consistently ensure that our power system is safe and sound. The planned work aims to maintain the plant safety level and reduce the risk of potential production losses due to possible faults and outages,” said Arvid Moss, executive vice president of Hydro’s Energy business area.

The work will start in 2011 and is planned to be completed in 2015. The investments will be distributed over the same four-year period.

Activities requiring total shutdown of all five power plants will be executed in two outage periods of about 16 weeks each, in 2012 and 2014.

“The waterfalls at Rjukan have represented Hydro’s most reliable and predictable source of power through our 105-year history. We remain committed to keeping these assets a core part of Hydro also in the future,” Moss said.