In conjunction with the SINTEF research institute, Statkraft is conducting a project at Follsjø lake in Møre og Romsdal to measure greenhouse gas emissions.

Background
Hydropower reservoirs release carbon dioxide and methane into the atmosphere. How extensive these emissions are and whether they are man-made are subject to international debate. The IPCC (International Panel of Climate Change) has issued national emission guidelines which describe how hydropower reservoir emissions should be calculated.

The debate was prompted partly by reports of greenhouse gas emissions from a reservoir in the Amazon region in Brazil. This is an area which is very different to Norway with respect to temperature, amount of organic material and depth. In tropical areas dams are often shallow, forest and vegetation not cleared and the biomass not removed before damming.

Norwegian reservoirs are often high up in the mountains, with a rock base, and it is therefore assumed that the conditions needed for the production of significant amounts of methane are not present to the same extent.

There are few reliable measurements of such emissions, and even fewer calculations of net emissions. The IPCC has pointed out the need for more knowledge and more measurements.

The formation of carbon dioxide and methane is a natural process. The key issue is whether emission levels rise after damming, and whether this depends on where in the world reservoirs are located.

Implementation
In conjunction with the SINTEF research institute, Statkraft is conducting a project at Follsjø lake in Møre og Romsdal to measure greenhouse gas emissions. Follsjø contains 179 million m3 of water and covers an area of 6.5 km2. The dam was built in 1968 and its height above sea level varies from 375 m to 420 m. Measurement will take place in the period 2004-2008. 

Results

• Increased knowledge about greenhouse gas emissions from our reservoirs
• Local measurements