Hannah Hunt contributed to the analysis included in this report.
Wind energy saved 2.5 billion gallons of water in California in 2014 by displacing water consumption at the state’s thirsty fossil-fired power plants, playing a valuable role in alleviating the state’s record drought. Wind energy’s annual water savings work out to around 65 gallons per person in the state (200 gallons per household), or the equivalent of 20 billion bottles of water.
The executive order announced yesterday by Governor Jerry Brown is designed to reduce household water consumption by 25 percent, from about 140 gallons per day per household to 105 gallons per day. Wind energy’s water savings are therefore equivalent to what would be saved by nearly one week’s worth of the required reductions for a typical household.
Update: Replacing California’s entire remaining fossil fuel fleet would save an additional 18 billion gallons of water, bringing this to a total of roughly 45 days worth of the required household reductions.
One of wind energy’s most overlooked benefits is that it requires virtually no water to produce electricity, while almost all other electricity sources evaporate tremendous amounts of water. In 2008, the nation’s thermal power plants withdrew 22 to 62 trillion gallons of freshwater from rivers, lakes, streams, and aquifers, and consumed 1 to 2 trillion gallons. By displacing generation from these conventional power plants, U.S. wind energy currently saves around 35 billion gallons of water per year, the equivalent of 120 gallons per person or 285 billion bottles of water.
The 2.5 billion gallons of water savings for California were calculated using EPA’s AVERT tool, which AWEA used to determine which fossil-fired power plants in California are displaced by wind energy produced in California or delivered to the California power system. That power plant displacement information was then multiplied by the power plant-specific water consumption rates in the Union of Concerned Scientists database, to arrive at total water savings at the state’s power plants.
Drought is also affecting electricity production at California’s power plants, but wind energy is helping to keep the lights on
California is currently facing a record drought, and unfortunately scientists say it is being worsened by climate change. In addition to saving valuable water, wind energy is helping to guard against threats the drought poses to electric reliability as well. This is an even less frequently discussed aspect of the complex interrelationships in the energy-water nexus.
The drought has taken a toll on California’s hydroelectric generation, but wind energy is helping to pick up the slack. Last year, California’s hydroelectric generation was down 7,366 GWh from its 2013 levels. California-based wind generation more than made up for that shortfall, providing 13,776 GWh in 2014.
While the drought is imposing major costs on the state’s agriculture and Californians in general, it also poses challenges for electric reliability because the electricity system is so heavily dependent on water. Last summer, the California grid operator expected 18-22 percent of the state’s hydroelectric power plants to be unavailable to provide energy to meet peak system demands. That same summer, the grid operator noted that 1,150 MW of the state’s thermal power plants were at risk of having cooling water supply curtailments. The grid operator has not yet released its assessment for this summer, but given the worsening drought, the situation may be even more dire.
In addition to directly offsetting freshwater consumption at thermal power plants, wind energy helps combat the impacts of drought by allowing grid operators to save hydroelectric energy (in the form of water behind dams) until they need it to meet grid reliability needs. Wind energy almost always displaces energy that would have been produced by a fossil-fired power plant, though sometimes grid operators use wind energy to store additional water behind dams where it can be used later to displace fossil fuel generation. While a number of complex factors affect how dams use their water resources, the abundant supply of wind energy this spring has likely alleviated pressure on the operators’ need to use water to produce electricity, helping them maintain reservoir levels so they can continue producing power and providing grid reliability services through the summer. In addition, in most regions the variability of the wind energy resource from year-to-year is much lower than that of the hydroelectric resource, so adding wind energy improves the reliability and resilience of the electricity system.
The Union of Concerned Scientists’ large body of work on the energy-water nexus also illustrates that wind energy plays a vital role in diversifying our energy mix away from water-intensive sources, making our energy system more resilient in the face of worsening droughts from climate change. One UCS report highlights how severe droughts in various parts of the country have forced conventional generators offline by restricting cooling water resources during periods of peak electricity demand.
These events further underscore that the power system is most reliable with a diverse mix of energy resources, and that adding zero fuel use and virtually zero water use wind energy to the mix makes the system more reliable while protecting consumers from unexpected scarcity events.
Across the country, wind energy is ideally suited to help alleviate the impacts of drought. Through sheer coincidence, much of the nation’s wind generation happens to be located in regions that are most prone to drought, as indicated in the following map. In particular, the agricultural Midwest is home to most of the nation’s wind generation, which has helped reduce consumption of valuable water at the region’s power plants, saving it for use on the region’s vast farmland. Wind’s benefit in the Midwest is particularly large, as the region’s fossil-fired power plants use even more water than those in California and other regions, given the greater use of water-intensive steam-based coal power plants instead of gas combined cycle power plants.