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Tuesday, March 2, 2010

Energy From Osmosis

From our friend Madhava Ghosh's blog "View From A New Vrindaban Ridge"

The Norwegian company Statkraft opens the world’s first facility for osmotic power generation. Statkraft says a full-scale commercial osmotic power plant could be ready by 2015.

Salt is good for you. When salt and fresh water mix, you can  generate clean energy. (Photo: Statkraft)

Salt is good for you. When salt and fresh water mix, you can generate clean energy. (Photo: Statkraft)

Osmotic power could contribute around 1,600 TWh on a global basis annually. Only in Norway 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 SodraCell 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 power 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.

About Statkraft:

The Statkraft Group generates hydropower, wind power and district heating and constructs gas power plants in Norway and Germany. Statkraft is a major player on the European energy exchanges. In Norway the company supplies electricity and heat to around 600,000 customers through its shareholdings in other companies.

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