06 August 2012

The Energy-Water Collision

It struck me this weekend that I've seen a great number of fairly accurate infographics about water that have been produced in the past few years, so maybe these will become a weekend thing here... The graphic below from the Union of Concerned Scientists was recently posted by Twitter friend @_ColinS_ at his new gig for Smithsonian.com. Make sure to see my NOTEs at the bottom here as well.

NOTE 1: While thermoelectric (coal, natural gas, and nuclear) power plants in the US account for 41% of our national freshwater withdrawals, only approximately 2.5% of that cooling water is "consumed" by conversion to steam. The remainder is discharged from the plant to receiving waters, where thermal pollution (as shown in the graphic) is one of the principal impacts of thermoelectric energy generation on surface water resources in the US. See also the 2003 National Renewable Energy Laboratory Technical Report No. 550-33905, "Consumptive Water Use for U.S. Power Production" (pdf).

NOTE 2: While wind turbines and photovoltaic solar panels do not require water for operation, their manufacture/construction process requires much water and energy. Ultra-pure water, used for silicon-based PV panels, is generated by an energy-intensive process. Both technologies use heavy metals and rare-earth elements in their manufacture; metals-laced mining and manufacturing wastes remain a water quality issue in the US. Wind turbines also require mechanical lubricants and other dielectric materials that necessitate proper disposal practices.

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