Further climatic changes attributed to greenhouse gases and global warming has focused a great deal of that development effort toward "green" and renewable resources.
Osmotic Power, a concept very well defined for almost 50 years has been greatly enabled by the recent developments in the pressure exchanger. This technology which can create clean energy by taking advantage of the natural force of osmosis between water bodies with different salinities separated by a semi-permeable membrane is very close to being viable with 2-3 of the major equipment components presently commercially available at or very near the levels required for production, including the ERI Pressure Exchanger™ device (PX).
The basics of osmotic power can be described as a technology that utilizes the power released when freshwater mixes with saltwater. Hence it is somewhat of a reverse process of desalination. Pressure retarded osmosis, or the PRO concept harnesses the energy in this process to run turbines.
As freshwater passes through a semi-permeable membrane to a saltwater chamber with limited volume, pressure will theoretically rise to a maximum of 26 bars. The operating pressure in a power plant will be in the range of 11 to 15 bars, an equivalent to a water head of 100 to 145 meters in a hydropower plant, generating about 1 MW/m3s freshwater.
Osmotic power plants can be designed for installation in a number of coastal sites. A sea level PRO power plant can be designed as a run-of-the-river hydropower plant, as it takes freshwater in from a river outlet. Another is a combined conventional SHP and membrane plant that is buried in appropriate geological sites near the coastline, utilizing gravity for extra pressure. Many other flexible applications are possible.
Osmotic power is highly efficient and can operate at full capacity for more than 7000 hours a year. As it is an environmentally safe technology that exploits natural power in an area that has not been fully explored yet, there is great potential in the future for expanding its use, especially in countries with narrow land mass or those that needs alternative renewable energy sources.
Source: http://osmoticpower.com/
