A Low-Water Energy Future Isn’t Necessarily Low-Carbon

Planning for a low-carbon energy future is not the same as planning for a low-water energy future, according to new research from Massachusetts Institute of Technology (MIT).

There is a lack of Academic research that compares carbon emissions, water use, and cost, according to lead author Mort Webster, an associate professor of engineering systems at MIT. “When we started this work,” he said in a statement, “we assumed that the basic work had been done, and we were going to do something more sophisticated. But then we realized nobody had done the simple, dumb thing.”

Although there may be a dearth of academic research looking at the exact question Webster was asking, there has been plenty of other research and action that shows governments, utilities and environmental groups are increasingly examining the issue and developing policies that address water, energy and climate change simultaneously.

Three years ago, IEEE Spectrum reported extensively on the water-and-energy crisis. The coverage included models that engineers were developing to look at not just the nexus of water, energy, and carbon, but also air, soil and pollutants. The special issue also looked at how regions as diverse as, say, Australia, Singapore, and California are addressing climate, water, and energy issues.

Last year, the Union of Concerned Scientists (UCS) [PDF] included the issue of water use related to energy production as its own section within UCS’s annual report for the first time. Another report from the International Energy Agency found that about 15 percent of the world’s total water withdrawal goes to energy production, and that figure could increase by about 20 percent between 2010 and 2035.

Webster’s research, which appeared in Nature Climate Change, found what others in the industry already know: limiting carbon dioxide emissions and water usage at the same time requires a different balance of technologies than does just doing one or the other.

Nuclear power, for example, is low on the carbon spectrum compared to coal, but uses a lot of water. Even some more energy-efficient fossil fuel power plants can significantly cut CO2 emissions, but use more water as a result. Hydropower is low-carbon, but requires a steady supply of water. Wind and solar photovoltaic are both relatively low-carbon and low-water energy technologies, but concentrating solar power plants use more water than new coal-fired power plants. The UCS report found that the increase in water withdrawal by the power industry would be driven by higher-efficiency power plants and expanding biofuels production.

Water concerns are not necessarily taking a backseat to meeting renewable energy portfolio standards and carbon reduction goals. Black & Veatch has found that power utilities identify water supply issues as a bigger concern than nuclear disposal or carbon regulation.

In the Western United States, some power producers are already planning for a low-water future while trying to keep hydropower as a part of the energy mix. For the first time, India, which has growing power needs and water constraints, has identified water as a scarce natural resource in its most recent five-year plan.

But there is a way forward that can take both carbon and water into account. Energy efficiency throughout the entire power sector, from production, to delivery, to end-use, is one way to curb both water and carbon emissions.

As wind and solar PV come down in price, the renewables are also becoming more cost competitive and could displace some of the older, most water- and energy-intensive fossil fuel plants.

Photo: iStockphoto

 

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