By Melissae Fellet
Electricity production is one of the industries that uses the most water in the country each day. Researchers at Sandia are helping the largest power plant in the United States identify the most efficient and cost-effective strategies to reduce water use. They have developed a first-of-its-kind comprehensive system dynamics analysis that can show power plants which wet cooling systems can save them money.
The analysis could eventually be used at other plants as federal regulators begin to reduce the power industry’s allowed water supply. The researchers have also redesigned and patented an air-cooling system to make waterless cooling more energy efficient and possible over a wider range of operating conditions.
The Palo Verde Nuclear Generating Station near Phoenix, Arizona, converts heat from nuclear reactions into electricity. The heat boils water, creating steam that drives turbine generators. Steam leaving a turbine must be cooled and condensed before it is reused.
More than 40% of the country’s water is used for wet cooling at power plants. Typically, large thermoelectric power plants are located near lakes or rivers so that operators can draw a regulated amount of water, run it through a condenser to cool steam leaving the turbines, and discharge roughly the same amount they withdrew.
The Palo Verde plant has limited access to water because it is in the middle of a desert. Its cooling water is treated wastewater, which is becoming increasingly expensive as other customers — who are willing to pay higher prices for water — emerge. To curb rising costs, operators want to reduce the plant’s water use by about 9 million gallons a day.