Energy Generation’s Water Demands a Huge ‘Hidden Cost’
Huge demands on increasingly scarce water are a major hidden cost of a “business as usual” approach to American electricity generation that needs to be more fully understood by policymakers and the public, according to research by Synapse Energy Economics.
For example, nuclear power has critical cooling requirements that require enormous amounts of water, according to The Hidden Costs of Electricity: Comparing the Hidden Costs of Power Generation Fuels, which was prepared by Synapse for nonprofits the Civil Society Institute and the Environmental Working Group. Roughly 62 percent of US nuclear plants have closed-loop cooling systems. Such reactors withdraw between 700-1,100 gallons of water per MWh and lose most of that water to evaporation. Water withdrawals are even higher at open-loop cooled nuclear plants, which need between 25,000-60,000 gallons per MWh. Most of this water is returned, but at a higher temperature and lower quality, the report says.
A similar story is true of coal-fired power, which also relies heavily on water for cooling, according to the report. Coal power stations with closed-loop cooling systems withdraw between 500 and 600 gallons of water per MWh and lose most of this via evaporation. Withdrawals for open-looped cooled coal-fired power plants are between 20,000-50,000 gallons per MWh. As with nuclear, most of the water is returned, but at a higher temperature and lower quality.
In 2010, the EPA estimated that the hydraulic fracturing of shale wells can use anywhere from two to 10 million gallons of water per well, Synapse says. Even green power sources such as biomass plants are water intensive, the report says. A typical 50 MW biomass plant could withdraw roughly 242 million gallons of water per year and lose most of this, the report says.
By contrast, wind and solar photovoltaic power requires little water in the electricity generation process. Concentrating solar power requires water for cooling purposes, but new technologies are placing greater emphasis on dry cooling. Solar power plants with dry cooling use only around 80 gallons per MWh – about a tenth of the low-end estimate for nuclear power and one-sixth of the low-end estimate for coal-fired power generation, the report says.
In July the EPA announced it would delay finalizing standards for cooling water intake structures at industrial facilities, giving power plants and factories almost a full additional year before they have to comply with a rule staunchly opposed by utilities. The rule, under section 316(b) of the Clean Water Act, requires the location, design, construction and capacity of cooling water intake structures to reflect the best technology available for minimizing adverse environmental impact. The regulations would require permits for facilities that use large volumes of cooling water from lakes, rivers, estuaries or oceans to cool their plants.
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