ENERGY: THE WATER FACTOR
Submitted by New Energy News Blog
Water is a big deal. Even the few climate change deniers left can’t deny droughts are becoming more common.
40% of the daily water used in the U.S. is for energy. It only makes sense to build the kind of energy infrastructure that least impacts water supply.
When cities use water to generate power, the water table drops. Eventually, the water table comes back up as the water is recycled. But it is possible for severe shortages and serious consequences to occur in the process.
Jaques Cousteau: “…sometimes we forget that the water cycle and the life cycle are the same.”
In The Water Cooler; The intertwined tale of energy and water, a new study from Virginia Tech researchers Rachelle Hill and Tamim Younos, hydropower, which requires lots of water but doesn’t consume any and doesn’t take any out of the cycle at all, is rated much more highly (only 20 gallons/million BTUs) than nuclear power, which uses the most water of any power generation process (2,400 gallons/million BTUs).
Wind energy’s water consumption is so negligible it wasn’t even considered.
A nuclear energy industry spokesman was quick to point out that, overall, energy production uses 3% of water consumed while agriculture uses 81%. Tony Pietrangelo, vice president of regulatory affairs, Nuclear Energy Institute: “In the overall scheme of things, 3 percent is a small fraction…But, from the carbon standpoint, CO2 emissions (from power generation) can be a major contributor to greenhouse gas levels.”
The study focuses on water but includes observations about greenhouse gas (GhG) emissions, pointing out that both must be considered in choosing what energy infrastructure to build. From the GhG standpoint, nuclear is probably better than coal. But – all things considered – a solar power plant (230 gallons/million BTUs) is a vastly superior choice than a coal-fired power plant (1,100 gallons/million BTUs) or a nuclear plant ( say it again! – 2,400 gallons/million BTUs).
Tamim Younos, Virginia Tech research professor/ study co-author: “Ten to 15 years down the road, if we keep doing what we’re doing (with water and energy), it will not be sustainable…”
In keeping with the rising tide of evidence against the value of biofuels for transportation, ethanol and biodiesel are much worse than any fossil fuel in terms of water consumption though biodiesel might warrant consideration in light of its possibly favorable GhG emissions. Ethanol gets an especially bad rap because the water used to grow crops may be contaminated by fertilizers and do special harm to the water supply.
More information is available from the Energy-Water Nexus, a study from a consortium of U.S. Dept. of Energy labs, from which the illustrations below were borrowed.
