Osmotic power
November 24, 2009
Osmosis could become the newest addition to the world's array of non-polluting, renewable energy sources. A power plant operated by Norway's Statkraft that generates electricity by harnessing the power of water moving through a membrane began operation on Tuesday.
The small-scale plant, located about an hour south of Oslo, includes two pressurized tanks separated by a polymer membrane filled with varying amounts of either fresh or salt water. Osmosis pulls fresh water into the saltwater tank, which increases the pressure on the saltwater side. The pressure of the moving water is enough to turn the turbine that creates energy.
"It is a form of renewable energy which, unlike solar or wind power, produces a predictable and stable amount of energy regardless of the weather," explained Stein Erik Skilhagen, in charge of the project at state-owned Statkraft.
Limited power
Statkraft said the plant is intended primarily for testing and will have a limited production capacity as the membranes undergo additional development in energy efficiency. Initially, the plant will produce only 2,000 watts to 4,000 watts hours per day - about enough to heat up a single-stove burner.
The membranes tested at the new plant will have an efficiency level of less than 1 watt per square meter. The company said it plans to install membranes that can deliver 2-3 watts per square meter after some time, but an efficiency level of 5 watts per square meter is needed to make osmotic power profitable.
"It is definitely a point to work on," Gerald Pourcelly of the European Membrane Institute told the AFP news agency. He said additional research and development could bring the membranes' efficiency level to 5 to 6 watts per square meter.
Statkraft has estimated the global potential of osmotic power to be between 1,600 and 1,700 terawatt hours per year, which is about 50 percent of the EU's total power production.
The company hopes to have a commercial-size plant up and running by 2015, producing about 25 megawatts (MW) of electricity, or enough for 10,000 homes.
sms/AFP/dpa
Editor: Mark Mattox