Renewables more water friendly than carbon capture, report said

Replacing old power plants with renewable energy could help ease both the carbon and water footprint, according to a study released Tuesday morning by the Union of Concerned Scientists.

The study recommends focusing on renewable energy rather than natural gas and nuclear power as a means for addressing both water and carbon concerns, as the country begins to replace many of its aging coal plants.

The major sources of electric generation – coal, natural gas and nuclear power – all require large amounts of water to create power. For example, more than 40 percent of U.S. freshwater withdrawals are used for power plant cooling, although more than 90 percent of this water is recycled.

“We set electricity and water on a collision course years ago,” said Peter Frumhoff, director of science and policy for the Union of Concerned Scientists, at a press conference on the report. “Now we must build a power system hard-wired not for risk, but for resilience.”

The discussion comes as Texas is facing the third year of what some say will be a drought more severe than the 1950s drought of record, making water supply reliability increasingly critical for electric generation.

Texas regulators are also reviewing generation capacity, in response to concerns about whether generation will be sufficient to meet growing peak demand.

More than 20 states have begun requiring utilities to submit water source plans in order to receive approval for new utilities, according to the report. In Texas, regulators denied developers of the proposed 1,320-megawatt White Stallion coal plant in Matagorda County a permit to withdraw 8.3 billion gallons of water annually from the state’s Lower Colorado River, because of competing water supply concerns.

While utilities are moving to natural gas, which uses less water than coal-fired generation, the water need could still harm water-strained areas, according to the report.

New carbon capture systems for coal and natural gas plants are being developed to reduce the carbon footprint, but the report notes that many of these solutions are still water intensive.

“Electricity mixes that emphasize carbon capture and storage for coal plants, nuclear energy, or even water-cooled renewables such as some geothermal, biomass, or concentrating solar could worsen rather than lessen the sector’s effects on water,” the report wrote.

Significant investment in renewables and energy efficiency would greatly reduce power generation’s water use and carbon emission, reducing water withdrawals by about 97 percent by 2050. Carbon emissions would also be reduced about 90 percent from current levels, according to the report.