Monday, July 23, 2012

Energy & Water are Closely Related

While we are always reminded in the media about the questions of energy security, water resources are equally important and increasingly linked to energy in what became known as the energy water nexus, or how much of each is needed to make the other available.

For the greater part of energy production water comes in as a very important input. It is necessary for oil fields development not only for drilling but to maintain production later and more is needed when enhanced oil recovery is practised. The World Energy Council (WEC) estimates an average of 40 barrels of water needed for the production of one barrel of oil. In today’s increasingly practised shale oil and gas development and oil extraction from tar sands or what is known as unconventional oil and gas, WEC estimates 90 to 150 barrels of water for each barrel of oil. The list goes on as four cubic metres of water are needed for every tonne of coal produced and in biofuel production the ratio is staggering at 1,100 litres of water for a litre of ethanol.

In electricity generation, thermal power stations in the US use 143 billion gallons of water every day, three times more than that used in public water supply and even more than irrigation use. Even hydroelectric power plants “consume” water due to the evaporation in the reservoirs that feed them. Therefore a shortage of water can inhibit the production of electricity or more energy is needed to bring water from far away sources. More


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