ENERGY: THE WATER FACTOR

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.

(From the Energy-Water Nexus - click to enlarge)

Analysis: Energy’s water demands Worrisome
Rosalie Westenskow, April 24, 2008 (UPI)

WHO
Rachelle Hill and Tamim Younos, study co-authors; Eric Evenson, U.S. Geological Survey; Mike Hightower, member, Energy-Water Nexus National Lab Team/technical staff member, Sandia National Laboratories; Kerry McCalman, power manager, Bureau of Reclamation/U.S. Department of Interior; Tony Pietrangelo, vice president of regulatory affairs, Nuclear Energy Institute

Choosing the right New Energy will determine if the answer turns out to be good news. (From the Energy-Water Nexus - click to enlarge)

WHAT
The Water Cooler; The intertwined tale of energy and water rates major sources of energy production and power generation according to their water use and consumption.

WHEN
Presently, droughts appear to be sporadic phenomena. If predictions about global climate change are accurate, drought will be an ongoing problem and having an energy infrastructure with lower water requirements in place will be a great advantage.

We CAN get there from here. (From the Energy-Water Nexus - click to enlarge)

WHERE
The U.S. Southeast, Australia and the Amazon region of South America are all currently struggling with drought.

WHY
- U.S. thermoelectric power plants consume 136 billion gallons of water per day, averaging out to 25 gallons for every kilowatt-hour produced. Uses: cooling and cleaning of machinery, steam to turn turbines.
From The Water Cooler:
- Energy Production Technologies:
Fuel – low range efficiency (gallons/million BTU)
Natural gas – 3 (gallons/million BTU)
Synfuel - Coal gasification – 11 (gallons/million BTU)
Tar sands -- 15 (gallons/million BTU)
Oil shale – 20 (gallons/million BTU)
Synfuel - Fisher Tropsch – 41 (gallons/million BTU)
Coal – 41 (gallons/million BTU)
Hydrogen – 143 (gallons/million BTU)
Liquid natural gas – 145 (gallons/million BTU)
Petroleum/Oil-electric sector – 1200 (gallons/million BTU)
Fuel ethanol – 2510 (gallons/million BTU)
Biodiesel – 14,000 (gallons/million BTU)
- Power generation techonologies:
Fuel – low range efficiency (gallons/million BTU)
Hydroelectric – 20 (gallons/million BTU)
Geothermal – 130 (gallons/million BTU)
Solar thermoelectric – 230 (gallons/million BTU)
Fossil fuel thermoelectric – 1,100 (gallons/million BTU)
Nuclear – 2,400 (gallons/million BTU)

(From the Energy-Water Nexus - click to enlarge)

QUOTES
- Rachelle Hill, co-author: "We need to do more research and really study what goes into energy production, not just what comes out…"
- Eric Evenson, U.S. Geological Survey: "Any one factor, like water needs for energy, or for public supply, or for agriculture … bears on the quantity of overall water availability…"
- Mike Hightower, Energy-Water Nexus National Lab Team: "In the United States on a daily basis, about 40 percent of our fresh water withdrawals are for energy production…Even if you don't consume a lot of water, if you use it, you need it day in and day out to operate…[If a drought occurs] then water levels lower, you can't withdraw any more and that's going to impact your energy supply."
- Kerry McCalman, power manager, Bureau of Reclamation/U.S. Department of Interior: "Hydropower generated by the Bureau of Reclamation as a whole offsets 31 million tons of CO2 emissions per year, on average…"
- Tony Pietrangelo, vice president of regulatory affairs, Nuclear Energy Institute: "Power production is not a significant consumer of water, especially compared to agriculture…"