Jul 21, 2009

Water is Missing from Renewable Energy Equation

The latest report from Lux Research, "Global Energy: Unshackling Carbon from Water," observes that while new energy sources and extraction methods may reduce carbon intensity, they often impose increased water usage.

"On a planet where only 0.008 percent of the water is renewable, such tradeoffs will become an increasingly important consideration for executives and policymakers," said Michael LoCascio, a senior analyst at Lux Research and the report's lead author. "Fortunately, many of the technologies and approaches needed to reduce water intensity are here today, or on the horizon."

The report, according to the company's press release, provides the most comprehensive analysis to date of how all the major conventional and alternative fuel and electricity sources balance their carbon dioxide and water intensity, as well as other important factors like cost and scalability. It also analyzes how alternative energy sources, improved extraction and efficiency, water recycling technologies, and improved energy distribution could help increase the environmental and economic viability for given energy technologies.

The report finds that:

  • Retrofits and upgrades will make coal and natural gas electricity sources more water and/or energy efficient. Representative solutions include boiler water treatments, like electrocoagulation, advanced ion exchange and membrane electrolysis, as well as dry condensers and cooling tower water recapture.
  • New and improved extraction technologies will be employed. Exploitation of oil sands and improved deep sea extraction will continue to make oil the cheapest, if dirtiest, source of energy for automotive drivetrains. But water recycling technologies like desalination and hydrocarbon recovery could reduce the water- and carbon-intensity of oil extraction from new sources like the tar sands.
  • The slow roll-out of transcontinental high-voltage DC transmission lines will hinder low-carbon, low-water energy sources like solar and wind. Biofuels use far too much water and are capable of providing too little energy to make up more than a few percent of global needs.
  • Nuclear is the only low-carbon, low-cost energy source that can reliably meet future electricity needs, but water is its Achilles' heel. However, advanced designs promise to increase efficiency and reduce water intensity, while placing plants on the coasts decouples them from increasingly scarce fresh water sources.
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