Statkraft osmotic power prototype is the world's first

osmotic power Osmotic power, salinity gradient power or blue energy is the energy available from the difference in the salt concentration between seawater and river water. Two practical methods for this are reverse electrodialysis (RED) and pressure retarded ...

plant, based on the energy of

osmosis Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of ...

. The power plant is run by

Statkraft Statkraft AS is a hydropower company, fully owned by the Norwegian state. The Statkraft Group is a generator of renewable energy, as well as Norway’s largest and the Nordic region's third largest energy producer. Statkraft develops and generates ...

. The power plant is located at Tofte in

Hurum Hurum was a municipality in Buskerud county, Norway. As of 1 January 2020 Hurum has merged with the municipalities of Røyken and Asker to form the new Asker Municipality located in the newly formed Viken county. The administrative centre of the ...

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

, with rooms at the factory area at

Södra Cell Tofte Södra Cell Tofte is a pulp mill located at Tofte in Buskerud, Norway. The plant dates back to 1897 when Tofte Cellulosefabrik was founded at the initiative of industrialist Anthon B. Nilsen. The raw material used at the plant is from euca ...

cellulose factory. The power plant uses the osmotic gradient that occurs when fresh water and salt water meet, separated by a permeable membrane. The salt water pulls fresh water through the membrane and the pressure increases on the salt water side; this pressure increase can be used to produce

electrical power Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of ...

with the use of a normal hydroelectric turbine/generator setup. The plant is a prototype developed together with

Sintef SINTEF ( no, Stiftelsen for industriell og teknisk forskning), headquartered in Trondheim, Norway, is an independent research organization founded in 1950 that conducts contract research and development projects. SINTEF has 2000 employees from 7 ...

and began test power production on 24 November 2009.

Mette-Marit, Crown Princess of Norway Mette-Marit, Crown Princess of Norway (born Mette-Marit Tjessem Høiby, , on 19 August 1973) is the wife of Crown Prince Haakon. Haakon is the heir apparent to the throne, which means that should he ascend to the throne, she will automaticall ...

, officially opened the plant. This plant had been planned since the summer of 2008, with a water usage of 10 litres of fresh water and 20 litres of salt water per second. It is expected to give a power output of between 2-4 kW. With better membranes it is assumed that the power for a similar plant can be increased to about 10 kW. A commercial plant is expected to be built between 2012 and 2015. In 2013, Statkraft announced that is discontinuing its work to develop osmotic power technology. The larger planned pilot facility, and the future commercial plant, will not be built.
Statkraft halts osmotic power investments

Advantages

This type of power generation is very reliable, consisting of only slightly more moving parts than a conventional hydroelectric power plant; in this case the addition of a pair of small pumps to move the fresh and salt water to the membrane surfaces. It is very quiet when operating and requires minimal supervision. In addition, it is expected the plant could respond very quickly as an emergency power source, using the membranes to 'store' power ready in the form of high pressure water; this water could be very quickly fed to the hydroelectric turbine to generate electricity. The expected lifetime of this plant is large; with almost no moving parts (those that do move are very simple and reliable), there will be little wear occurring. The availability of spare parts and upgrade components is also good, meaning that an installed osmotic power plant could be run for many years cost-effectively.

Disadvantages

Whilst highly reliable, simple and cheap to run/maintain, this plant is very expensive to install. The permeable membrane is currently an expensive resource, and to have any meaningful output, a very large membrane area is required. The plant described in this article could reach a power output of 4 kW in ideal conditions. By comparison, an open cycle gas turbine a fraction of the size (such as the Rolls-Royce or GE aero-derivative gas turbines) could easily produce greater than 15MW for a fraction of the installation costs, although fuel and maintenance costs would be greater. This is an increase in power output 3750 times greater, with a land usage that is much smaller. Comparing the ideal power output of this plant to the rough average household consumption of a modern home detailed in the article

domestic energy consumption Domestic energy consumption is the total amount of energy used in a house for household work. The amount of energy used per household varies widely depending on the standard of living of the country, the climate, and the age and type of residence. ...

, it can be seen that this is a very limited technology - working back the figures, it equates that the average home requires 2 kW of power. Bear in mind however that advances in materials technology will likely greatly increase the power output per plant volume over time and thus make this a more useful form of power generation, particularly in remote locations where reliability is key and spare parts are difficult to come by (e.g. difficult-to-access coastal locations with a small stream or river nearby that can provide the fresh water required).

References

External links

Statkraft
- «Saltkraft», presentasjon oktober 2009.
Statkraft
- «Verdens første saltkraftverk åpnet!», 24. November 2009. {{coord, 59, 32, 52, N, 10, 33, 56, E, region:FR_type:city_source:kolossus-frwiki, display=title Sustainable technologies Sustainable energy Water power Renewable energy power stations in Norway Statkraft Membrane technology Hurum