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Rivers flowing into the sea offer vast potential as electricity source

Date:
April 18, 2012
Source:
American Chemical Society
Summary:
A new genre of electric power-generating stations could supply electricity for more than a half billion people by tapping just one-tenth of the global potential of a little-known energy source that exists where rivers flow into the ocean, a new analysis has concluded. The process requires no fuel, is sustainable and releases no carbon dioxide (the main greenhouse gas).
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Coastline where a river meets the sea near Belfast, in Northern Ireland.
Credit: © marcel / Fotolia

A new genre of electric power-generating stations could supply electricity for more than a half billion people by tapping just one-tenth of the global potential of a little-known energy source that exists where rivers flow into the ocean, a new analysis has concluded. A report on the process -- which requires no fuel, is sustainable and releases no carbon dioxide (the main greenhouse gas) -- appears in ACS' journal Environmental Science & Technology.

Menachem Elimelech and Ngai Yin Yip explain that the little-known process, called pressure-retarded osmosis (PRO), exploits the so-called salinity gradient -- or difference in saltiness -- between freshwater and seawater. In PRO, freshwater flows naturally by osmosis through a special membrane to dilute seawater on the other side. The pressure from the flow spins a turbine generator and produces electricity. The world's first PRO prototype power plant was inaugurated in Norway in 2009. With PRO appearing to have great potential, the scientists set out to make better calculations on how much it actually could contribute to future energy needs under real-world conditions.

Elimelech and Yip concluded that PRO power-generating stations using just one-tenth of the global river water flow into the oceans could generate enough power to meet the electricity needs of 520 million people, without emitting carbon dioxide. The same amount of electricity, if produced by a coal-fired power plant, would release over one billion metric tons of greenhouse gases each year.

The researchers acknowledge funding from the Environment and Water Industrial Development Council of Singapore for Ngai Yin Yip's fellowship.


Story Source:

The above post is reprinted from materials provided by American Chemical Society. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ngai Yin Yip, Menachem Elimelech. Thermodynamic and Energy Efficiency Analysis of Power Generation from Natural Salinity Gradients by Pressure Retarded Osmosis. Environmental Science & Technology, 2012; 120413085012007 DOI: 10.1021/es300060m

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American Chemical Society. "Rivers flowing into the sea offer vast potential as electricity source." ScienceDaily. ScienceDaily, 18 April 2012. <www.sciencedaily.com/releases/2012/04/120418135134.htm>.
American Chemical Society. (2012, April 18). Rivers flowing into the sea offer vast potential as electricity source. ScienceDaily. Retrieved July 4, 2015 from www.sciencedaily.com/releases/2012/04/120418135134.htm
American Chemical Society. "Rivers flowing into the sea offer vast potential as electricity source." ScienceDaily. www.sciencedaily.com/releases/2012/04/120418135134.htm (accessed July 4, 2015).

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