Osmotic Power Generation

Published on 02 Jul 2021. Written by Dineshkumar E

Energy consumption is an important aspect in our day to day life and it is increasing very rapidly if this continues as such then the world will one day face a shortage of energy. Osmosis is a natural process used to generate power. The mixing of freshwater and seawater delivers massive amounts of energy that can be utilized for power production.

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Osmotic power produces energy without the emission of CO2. The major source of low cost, conventional energy is fossil fuels. However, fossil fuels are non-renewable energy sources and CO2 emissions are also more compared to renewable energy sources.

Project Description

This project works on the principle of Osmosis. Osmosis is the passage of solvent molecules through a selectively permeable membrane from an area of lower concentration to an area of a higher concentration, intending to balance the concentrations on both sides. In Osmotic Power generation the energy is available from the variation in salt concentration in seawater and river water. Freshwater moves through the membrane to seawater by osmosis. Thus, osmotic powerplants are built where freshwater flows into the sea.

Membrane: It is used to separate the saltwater from freshwater so that the osmosis process will occur. The membrane should own properties like great water permeability, low salt permeability and low resistance in the assisting layer of the membrane.

Pressure Retarded Osmosis: This is the technique employed to produce power from salinity gradient energy resulting from the variation in salt concentration between saltwater and freshwater. It contains two chambers separated by a semi-permeable membrane to store freshwater and saltwater. The freshwater will flow through the membrane towards the seawater. The pressure in the seawater container is raised as the salt in the seawater brings the fresh water through the membrane. Thus, the pressure is produced by transferring water into the membrane. This pressure is used for two purposes: One part of the pressure is used to rotate the turbine to generate power and the other part is used to pressurize the incoming seawater.

Pre-treatment of the water is done depending on the water qualities to prevent clogging and gradual degradation of the membrane.

Advantages

1. These powerplants are steady and we can get predictable output.
2. Adaptable for small or large generating stations.
3. Modular design (membrane modules added as required) making it possible to increase the installed capacity.

Conclusion

Osmotic power is one of the several encouraging renewable ocean power sources. The estimated energy cost is comparable and competitive with other renewable energy sources. The osmotic power plant will not release any pollutants to the environment and not affect the seafloor or the river habitat.

Kit required to develop Osmotic Power Generation:

• turbine
• membrane

Technologies you will learn by working on Osmotic Power Generation:

• osmosis

Any Questions?