Assessing carbon pollution standards: Electric power generation pathways and their water impacts

This study evaluates transition pathways in electricity generation and their future water impacts. Scenarios that do or do not comply with the carbon pollution standards - based on the U.S. New Source Performance Standards and Clean Power Plan - are evaluated. Using the Electric Reliability Council of Texas region as an illustration, the scenarios with carbon regulations are shown to have lower CO2 emissions and water use from the power sector than the continuation of the status quo with more electricity generation from coal than natural gas. The benefits are due to increases in electricity generation from renewable sources and natural gas combined cycle (NGCC) plants plus retirements of existing coal-fired plants, which depend on natural gas and CO2 allowance prices. When CO2 is captured and sold for enhanced oil recovery with a price higher than $15 per short ton, water consumption is elevated because of more electricity generation from existing NGCC plants retrofitted with carbon capture and storage (CCS) technology. A stringent constraint on water withdrawals decreases electricity generation from existing power plants with once-through cooling, but increases overall water consumption because of an elevated share of plants with wet recirculating cooling systems in the fleet.