Norway plan to build world’s first osmosis based power plant

Even a calm sea contains a large amount of energy. Where fresh water and salt water meet this potential can be exploited through osmosis, for example where a river runs into the ocean. With a membrane dividing fresh and salt water, osmosis will make the fresh water mix with the salt water creating a surplus of water on the salty side. This flow of water can be used to produce power. The force of osmosis can raise the water 120 metres which is comparable to a huge waterfall.

Osmotic power could contribute around 1,600 TWh on a global basis annually. In Norway alone, osmotic power has the potential to cover 10 percent of the total power consumption.

Natural process

Osmotic power is based on the natural process of osmosis. In an osmotic power plant, seawater and fresh water are separated by a membrane. The seawater draws the fresh water through the membrane, thereby increasing the pressure on the seawater side. The increased pressure is used to produce power.

Supply of fresh and salt water

The Statkraft prototype plant is built at the paper pulp manufacturer Sodra
Cell Tofte's plant at Hurum in Buskerud, Norway. The location will provide the osmotic plant with a good supply of fresh water and seawater, along with access to the established infrastructure.

Large investment

When Statkraft started the establishment of an osmotic power plant prototype, the company had invested more than NOK 100 million to develop a new, renewable energy technology. The research work was supported by The Research Council of Norway, the prototype is also being supported by the the public enterprise Enova SF. Enova SF is owned by the Royal Norwegian Ministry of Petroleum and Energy and its main mission is to contribute to environmentally sound and the rational use and production of energy. The prototype is meant to provide Statkraft with a better understanding of the challenges involved in developing osmotic power technology. StatoilHydro says the prototype built at Tofte is a necessary platform for the further development of the technology.

1970s idea

The idea to generate power through osmosis originates from the 1970s. But back then the membranes were not sufficiently effective and the apower prices were too low to enable anyone to profitably invest in such projects. Scientists at the research organisation SINTEF brought the idea to Statkraft in the 1990s.

Can be built out of sight

Around the world, rivers flow out into the sea in urban and industrial areas where it will be possible to construct osmotic power plants. A power plant the size of a football stadium could supply around 10,000 households with electricity. These power plants can be built underground, e.g. in the basement of an industrial building or under a park, minimising their visual impact. Statkraft points out that osmotic power plants give off no polluting discharges to the atmosphere or water, and that they do not affect the fauna or flora of rivers or the seafloor.