Dutch researchers are seeking to add a new, largely untapped renewable energy source to the world's energy mix with the opening of a "Blue Energy" test facility on Wednesday.

Blue energy takes advantage of the difference in salt concentration between sea water and fresh water to produce electricity. A similar test plant was launched in Norway in 2009.

One reason to try the system in the Netherlands is geography: the Rhine and Meuse rivers both meet the sea here. The plant is strategically located on the Afsluitdijk — the huge dike that turned part of the North Sea into a freshwater lake in the 1930s.

The multiyear project, funded by a mix of government and corporate sponsors, seeks to improve the system's efficiency until it is a profitable electricity source.