Energy Sector Impacts and Opportunities

The power sector is the largest user of freshwater in the U.S. The dominant use of water in power plants is for steam cycle cooling. The current portfolio of electricity generating technologies in the U.S. has highly regionalized and technology-specific requirements for water. Certain areas employ once-through cooling technologies with high withdrawals and low consumptive uses, whereas other areas employ recirculating cooling technologies with relatively low withdrawals but high consumptive uses. As water availability differs widely throughout the nation, assessments of water withdrawal and consumption impacts from the power sector must have a high geographic resolution and consider regional differences. The U.S. electricity portfolio is likely to evolve in coming years, shaped by various energy policies and economic drivers on both the national and regional level, which will impact power sector water demands. It is likely that the U.S. will continue to decarbonize its electricity industry, leading to more low-carbon technologies. However, many low-carbon technologies, such as coal with carbon capture and storage, nuclear, and concentrated solar power, can use more water than the current electricity portfolio average. National- and state-level water policies have been proposed (and enacted) that affect cooling system choices for power plants, with resulting implications for water use as well as power plant installed and operating costs and reliability. Energy policy analyses that do not consider power plant cooling system impacts may miss an important component power plant siting decisions. Similarly, water policies that do not take into consideration potential impacts on power plant operations or comprehensive regional water budget impacts may have deleterious effects on the energy industry. Analysis of future energy scenarios that incorporate technology options and constraints as well as different policies can provide useful insights about likely changes to both the technology mix and the nation's water resources. Utilizing the Regional Energy Deployment System (ReEDS) model, a national electricity-sector capacity expansion model with high geographical resolution, we explore the potential development of the U.S. electric sector under different energy, water, and integrated energy-water policies and examine the associated impacts at the regional level.