(117b) Water and Energy: Integrated Challenges, Integrated Solutions

Water, once considered a nearly inexhaustible resource, is becoming increasingly limited, and water requirements for electricity production must compete with other demands, such as agriculture and sanitation. The Department of Energy's (DOE) Fossil Energy Program is conducting a considerable R&D effort directed at the nexus between energy and freshwater resources. Much of this work is being conducted through DOE's National Energy Technology Laboratory. Research areas address improved freshwater management for thermoelectric power plants; reducing water impacts associated with carbon capture and sequestration; and reducing water impacts associated with natural gas and oil production.

Thermoelectric power plants (including coal, oil, natural gas, and nuclear), generate about 90% of the electricity in the United States, and require large quantities of cooling water, a resource that is limited in parts of the nation and throughout the world. Although commercially available cooling technology options can reduce or mitigate water consumption, they result in added cost, increased complexity, and reduce the amount of power available from the plant. DOE is developing new technologies that will reduce the cost and complexity of these systems under its Existing Plants R&D program.

Efforts to capture 90 percent of carbon emissions by using current near-commercial carbon capture and storage (CCS) technologies on coal-based power plants could more than double the amount of water consumed per unit of electricity generated. A key objective of DOE R&D activities is to mitigate the potential impact of CO₂ capture on water resources. This is being addressed under two key inter-related components of its R&D Program ? (1) the development of advanced CO₂ capture technologies that require less freshwater and (2) the development of advanced water management technologies that reduce freshwater usage throughout the power plant.

DOE is also addressing water-related issues associated with natural gas and oil production such as produced water and its effects on the environment, treatment of process waters, and the availability of water in arid lands. Produced water is the largest waste stream generated by the oil and natural gas industry. DOE's Oil and Natural Gas Program strategies related to water resources include: enabling sustainable oil/gas water management options that support regional and basin-oriented oil and gas development strategies; developing technologies to improve environmental performance and reduce costs; developing scientific and technical information and decision making tools for risk-based regulation and compliance; and increasing the understanding of environmental benefits and risks.