Saturday, October 20, 2012

Guide to osmotic energy

Some renewable energy sources are very familiar to large number of people such as wind and solar energy. This however, isn't the case with osmotic energy, and there aren't that many people who know great deal about this energy source. 

If we were to categorize osmotic energy we would have to put it in marine renewable energy sources because osmotic energy results as an encounter between freshwater and seawater.

The main advantage that osmotic energy has over other energy sources is its predictability. The predictability gives osmotic energy a major edge over solar and wind in terms of reliability, making it a stable source for generating electricity. Osmotic energy also doesn't depend as much on weather conditions like solar and wind energy do.

The main premise on which osmotic energy works is nature's balance, and its operating principle is based on the different concentration of liquids. The working principle of osmotic energy is not that complicated – in the moment when freshwater and seawater meet on either side of a membrane (a thin layer that is able to retain salt but lets the water through) freshwater is drawn towards the seawater side. Afterwards, the power of the flow moves pressure on the seawater side, and that pressure is what drives turbine, and this is how electricity is generated.

The name osmotic energy comes from the word osmosis, a well known term in the science of biology. In biology, osmosis is the process that allows plants to take water through their leaves. The process of osmosis is also used in modern industry, in water desalination facilities.

Norway was the first country that showed the world how osmotic power works in practice with the prototype of an osmotic power plant built on the banks of the Oslo fjord. Norwegian state-owned Statkraft company plans to create commercial-size osmotic power plant fully operating by 2015. This facility should have an output of 25 MW, enough to satisfy electricity demands of about 10,000 homes.

This is only a small-scale pilot project but osmotic energy has great potential for future clean energy projects. According to Statkraft osmotic power has potential to produce 1,700 terawatt hour (TWh) annually, which is around half of the current power production in Europe.

The global energy market accepts only efficient and cheap renewable energy technologies and osmotic energy still has plenty to improve in this sense. The first thing that needs to be improved is the energy efficiency of membranes. Membranes used in this project have an efficiency level of less than 1 watt per square meter, which is five times less of level needed to make osmotic power profitable (5 watt per square meter).

We are talking here about the renewable energy technology that has just started developing, so it's really no surprise that there is lot of work that still needs to be done. Osmotic energy certainly deserves a chance, if not for anything else than because of its excellent potential.