Energy and water are very closely linked, but those links are often overlooked, according to Stacy Tellinghuisen, Western Resource Advocates' senior energy and water policy analyst. Tellinghuisen works to promote energy policies that reduce the energy sector's impact on water resources.
Most forms of electricity require water, Tellinghuisen says, and thermal electric power plants use a fuel to heat water and generate steam, which is then used to turn a turbine and generate electricity. She says most of those power plants use cooling systems, which require water, to cool and condense that steam.
"A typical western coal plant would consume 500 to 600 gallons of water per megawatt-hour of electricity generated. On an annual basis, a typical large, western coal plant would consume around 25,000 acre-feet of water. To put that in perspective, it's enough water to meet the needs of between 100 and 200,000 people over the span of a year. So these are not inconsequential volumes of water. Wind power, in contrast, consumes no water in the electricity-generation phase. Water is also used to mine fuels to construct power plants and for other purposes. But even including these phases, wind consumes much much less water than conventional power plants."
Last year, Tellinghuisen wrote a report titled A Powerful Thirst: Managing the Electricity Sector's Water Needs and the Risk of Drought. In that report, she looked at how drought can and has affected the electricity sector in the past.
"In 2012, drought affected large swaths of the United States, including power plants around the country. In 2011 and 2012, the impacts in Texas are particularly severe, with the potential for brownouts and very high electricity prices. In the report, we also highlight several key recommendations for mitigating the impacts of future droughts. First, for electricity utilities to quantify and report water use. Second, for those utilities and regulators to value that water over the life of a power plant, for 30 or 40 years that a plant would be operating. And third, for utilities and regulators to recognize the risk of drought and to at least qualitatively describe how a portfolio of resources may mitigate that risk."
Tellinghuisen says that evaluation should reflect the risk of current droughts and potentially more severe droughts in the future, which are predicted through climate change.
In her report, Tellinghuisen cited two issues in a Texas case study.
"Parts of the state follow a prior appropriations system of allocating water rights. Under that system, the earliest water rights are the more senior water rights, regardless of the use. In the Texas drought, the state basically threw that system out the window in favor of preserving water for cities and power plants. So, in effect, the state curtailed water to some of these senior agricultural water users."
The other issue covered in this case study is how Texas' wind generation may have mitigated some of the impacts of the drought on the power sector, according to Tellinghuisen.
"Texas had over 10,000 megawatts of wind capacity in the ground. And a portion of that was generating electricity in the summer of 2011 when there were these water shortages at many of the state's thermal electric power plants. I think it's hard to quantify, but wind has probably served some role to mitigate the impact of drought by reducing the water used from aquifers or surface storage for energy generation."
Tellinghuisen says that's a long-term and short-term benefit when drought occurs.
Clean energy policies lead to greater investments in wind power and efficient use of water resources, and Tellinghuisen says those are important factors for state and federal regulators to recognize.