The Global View

How are water and energy linked?

Most forms of energy we produce also require us to use water, often lots of water.

Think of all the water needed to cool nuclear reactors, for example, or to generate steam to drive turbines in coal-fired power plants. Hydropower, obviously, couldn’t exist without water. Nor could biofuels … unless J. Craig Venter develops some really outrageous type of artificial algae.

So how much water goes into generating the energy we use? The Water Footprint Network gave these figures in its 2008 report on “Water Footprint of Bio-Energy and Other Primary Energy Carriers”:

  • Surface mining of coal: An average of 4 cubic meters (m3) of water per 1,000 gigajoules (GJ) of energy produced
  • Deep mining of coal: 12 m3 of water per 1,000 GJ
  • Coal plant operations: 90 m3 of water per 1,000 GJ
  • Total for all coal-related operations: 164 m3 of water per 1,000 GJ
  • Open-pit uranium mining: 20 m3 of water per 1,000 GJ
  • Uranium enrichment (gas centrifuge): 2 m3 of water per 1,000 GJ
  • Uranium enrichment (gaseous diffusion): 12 m3 of water per 1,000 GJ
  • Nuclear fuel processing: 50 m3 of water per 1,000 GJ
  • Total for all nuclear power-related operations: 86 m3 of water per 1,000 GJ
  • Onshore oil extraction and production: 6 m3 of water per 1,000 GJ
  • Enhanced oil recovery: 120 m3 of water per 1,000 GJ
  • Thermal steam injection for oil recovery: 140 m3 of water per 1,000 GJ
  • Traditional oil refining: 45 m3 of water per 1,000 GJ
  • Oil refining using reforming and hydrogenation: 90 m3 of water per 1,000 GJ
  • Total for all crude oil-related operations: 1,058 m3 of water per 1,000 GJ
  • Natural gas processing: 6 m3 of water per 1,000 GJ
  • Natural gas plant operations: 100 m3 of water per 1,000 GJ
  • Total for all natural gas-related operations: 109 m3 of water per 1,000 GJ
  • Electricity from hydropower: 22,300 m3 of water per 1,000 GJ
  • Electricity from solar thermal power: 265 m3 of water per 1,000 GJ
  • Electricity from wind energy: 0 m3 of water per 1,000 GJ

2 thoughts on “How are water and energy linked?”

  1. Good question: The Water Footprint Network report doesn’t address recycling, but a 1987 study by the Pacific Institute on “Corporate Reporting on Water” found that — at that time — only 1 out of 10 companies reporting on their water use addressed recycling.

    Some interesting findings from the Pacific Institute report:

    * The mining sector had the highest rates of reporting on water recycling
    * Just one out of nine refining companies reported on water recycling
    * Just one out of 13 utility companies reported on water recycling

    While this is an old study, it does explain why historical data on industry water recycling is hard to come by. Of course, ultimately, all water is recycled: there’s no escaping the hydrologic cycle. The question is, how long does that water take to re-enter oceans, streams and aquifers, and how much pollution does it carry with it when it does?

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