Via Coyote Gulch, a look back at a recent report by the Union of Concerned Scientists and a more recent editorial from the Denver Post:
Here’s a guest commentary about the report, running in The Denver Post (Alice Madden/Peter C. Frumhoff). Here’s an excerpt:
Electricity generation from coal and nuclear plants requires water — a lot of water compared to other fuel sources — to cool the steam they produce to make electricity. In Colorado, coal plants consumed some 80,000 acre-feet of water for cooling in 2008. That’s enough water to supply the city of Boulder for four years, or Denver for four months.
Colorado’s water consumption rates in energy production were highlighted in a recent report of the Energy and Water in a Warming World Initiative, a research collaboration between the Union of Concerned Scientists and a team of more than a dozen national scientists, including local experts at the University of Colorado, National Renewable Energy Laboratory and Western Resource Advocates.
For most conventional coal plants, the bottom line is this: To keep the lights on, keep the water coming. It’s easy to ignore this dependence when there’s plenty of water. But in a water-constrained future, is heavy reliance on coal the best choice when we have smart water energy choices?
Although extracting natural gas via hydraulic fracturing is placing growing demands on water resources, an efficient natural gas plant consumes far less water than a coal plant. And some, like the Front Range plant in Colorado Springs, cool with air instead of water.
By contrast, wind and solar photovoltaics use virtually no water, making them smart energy choices for water-constrained states. Fortunately, Colorado has had impressive growth in both. That’s thanks in part to the Renewable Portfolio Standard law that requires investor-owned utilities Xcel Energy and Black Hills to produce at least 30 percent of the energy they generate from renewable sources by 2020, a goal both companies will meet easily. The remaining utilities, which provide about 40 percent of the state’s energy, must only meet a 10 percent RPS and rely heavily on coal.
Here’s the link to the report: Freshwater Use by U.S. Power Plants: Electricity’s Thirst for a Precious Resource (2011). Here’s the executive summary:
Across the country, water demand from power plants is combining with pressure from growing populations and other needs and straining water resources—especially during droughts and heat waves:
• The 2011 drought in Texas created tension among farmers, cities, and power plants across the state. At least one plant had to cut its output, and some plants had to pipe in water from new sources. The state power authority warned that several thousand megawatts of electrical capacity might go offline if the drought persists into 2012.
• As drought hit the Southeast in 2007, water providers from Atlanta to Raleigh urged residents to cut their water use. Power plants felt the heat as well. In North Carolina, customers faced blackouts as water woes forced Duke Energy to cut output at its G.G. Allen and Riverbend coal plants on the Catawba River. Meanwhile the utility was scrambling to keep the water intake system for its McGuire nuclear plant underwater. In Alabama, the Browns Ferry nuclear plant had to drastically cut its output (as it has in three of the last five years) to avoid exceeding the temperature limit on discharge water and killing fish in the Tennessee River.
• A 2006 heat wave forced nuclear plants in the Midwest to reduce their output when customers needed power most. At the Prairie Island plant in Minnesota, for example, the high temperature of the Mississippi River forced the plant to cut electricity generation by more than half.
• In the arid Southwest, power plants have been contributing to the depletion of aquifers, in some cases without even reporting their water use.
• On New York’s Hudson River, the cooling water intakes of the Indian Point nuclear plant kill millions of fish annually, including endangered shortnose sturgeon. This hazard to aquatic life now threatens the plant as well. Because operators have not built a new cooling system to protect fish, state regulators have not yet approved the licenses the operators need to keep the plant’s two reactors running past 2013 and 2015.
• Proposed power plants have also taken hits over water needs. Local concerns about water use have scuttled planned facilities in Arizona, Idaho, Virginia, and elsewhere. Developers of proposed water-cooled concentrating solar plants in California and Nevada have run into opposition, driving them toward dry cooling instead.
This report—the first on power plant water use and related water stress from the Energy and Water in a Warming World initiative—is the first systematic assessment of both the effects of power plant cooling on water resources across the United States and the quality of information available to help public- and private-sector decision makers make water-smart energy choices.
Our analysis starts by profiling the water use characteristics of virtually every electricity generator in the United States. Then, applying new analytical approaches, we conservatively estimate the water use of those generators in 2008, looking across the range of fuels, power plant technologies, and cooling systems. We then use those results to assess the stress that power plant water use placed on water systems across the country. We also compare our results with those reported by power plant operators to the U.S. Energy Information Administration (EIA) for 2008.
We examine both the withdrawal and consumptionof freshwater. Withdrawal is the total amount of water a power plant takes in from a source such as a river, lake, or aquifer, some of which is returned. Consumption is the amount lost to evaporation during the cooling process. Withdrawal is important for several reasons. Water intake systems can trap fish and other aquatic wildlife.
Water withdrawn for cooling but not consumed returns to the environment at a higher temperature, potentially harming fish and other wildlife. And when power plants tap groundwater for cooling, they can deplete aquifers critical for meeting many different needs. Consumption is important because it too reduces the amount of water available for other uses, including sustaining ecosystems.
While our analysis focuses on the effects of water use by power plants today, we also consider how conditions are likely to change in the future. In the short run, our choices for what kind of power plants we build can contribute to freshwater-supply stress (by consigning an imbalanced share of the available water to power plant use) and can affect water quality (by increasing water temperatures to levels that harm local ecosystems, for example). Over a longer time frame, those choices can fuel climate change, which in turn may also affect water quantity (through drought and other extreme weather events) and quality (by raising the temperature of lakes, streams, and rivers). Population growth and rising demand for water also promise to worsen water stress in many regions of the country already under stress from power plant use and other uses.
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