Something New: Osmotic Power | Green Energy News

November 28, 2009 – Vol.14 No.36

SOMETHING NEW: OSMOTIC POWER.
by Bruce Mulliken, Green Energy News

The following are the overly simplified steps to build a new source of clean, renewable energy for the planet::

1) Take a pressure vessel and divide it into two chambers.

2) Somewhere in the division of the chambers install the same type of semipermeable membrane used in reverse osmosis to make fresh water from sea water.

3) Attach a water pressure-driven turbine generator through piping to the chamber of the vessel that will hold sea water.

4) Fill, but not completely, the turbine-attached chamber with sea water. Fill the other with fresh water to about the same level.

5) Stand back and wait: The salt molecules on the sea water side will pull freshwater through the membrane increasing the pressure on the sea water side as the salinity equalizes (That pressure equals 12 bar or about 175 pounds per square inch (psi), a significant head of water.)

6) Allow the pressurized water to flow through the turbine: let it spin to drive the generator to make electricity.

7) Let the electricity do some work, like light some lights.

8) Give it a name, “Osmotic Power” or its other more scientific name “Pressure Retarded Osmosis (PRO).”

There’s certainly a lot more to Osmotic Power than described above: many vessels and membranes are needed for example. But the technology works. The first prototype osmotic power plant is now operating – in Norway.

Statcraft, Europe's largest renewable energy company, and global partners have been developing osmotic power for a decade and are now introducing it to the world by opening the prototype at Tofte near Oslo, which took about a year to build.

Unlike wind and solar, osmotic power can operate 24/7. Osmotic power plants could be built wherever a fresh water river empties into the ocean. In the U.S., think the Mississippi River, the Hudson River, the Columbia River and many, many others. Statkraft says the global potential of osmotic power is estimated to be 1,600-1,700 terra-watt hours (TWh) per year or about half of the European Union’s total power production.

Statkraft notes that osmotic power plants can be integrated into existing industrial zones, for example, in the basements of industrial buildings.

If there’s an environmental concern it might be that the discharged brackish water from the plant would upset the normal salt/water concentration in the nearby river. However, one would think that if closely monitored and with water discharged at the proper point in the river that the natural concentration would be kept in check.

Cost of a full-sized power plant is unknown at this time.

With the new demonstration prototype unit now operating it’s time to add osmotic power to list of emission-free renewable energy technologies now possible.

statkraftop526

Mixing seawater and fresh water for renewable energy 24/7. The prototype Osmotic Power plant in Norway.

As Statkraft CEO and President, Bard Mikkelsen said, "This new technology generates electricity simply by mixing water. New solutions to meet the climate challenges might be closer than we expect, which makes me confident that the future looks bright."

A commercial osmotic power plant is a few years away according to Statkraft. The innovative Norwegian energy group develops and generates hydropower, wind power, marine energy, solar energy, gas power and district heating, and is a major player on the European power exchanges.

Links:

Statkraft
http://www.statkraft.com

http://www.statkraft.com/energy-sources/osmotic-power/