EROWI – Energy Return of Water Invested
via [ The Oil Drum ]
The data in the table originate from “Energy demands on water resources”, report to the congress, 2006 [ link ]
For the past century, America has invested significant research, development, and construction funding to develop both fresh surface- water and groundwater resources. The result is a water infrastructure that allows us to harness the vast resources of the country’s rivers and watersheds, control floods, and store water during droughts to provide reliable supplies of freshwater for agricultural, industrial, domestic, and energy uses. During this same period, the U.S. developed extensive natural resources such as coal, oil, natural gas, and uranium and created an infrastructure to process and transport these resources in an efficient and cost-effective manner to consumers. These two achievements have helped stimulate unprecedented economic growth and development.
However, as population has increased, demand for energy and water has grown. Competing demands for water supply are affecting the value and availability of the resource. Operation of some energy facilities has been curtailed due to water concerns, and siting and operation of new energy facilities must take into account the value of water resources. U.S. efforts to replace imported energy supplies with nonconventional domestic energy sources have the potential to further increase demand for water.
ENERGY AND WATER INTERDEPENDENCIES
Water is an integral element of energy resource development and utilization. It is used in energy-resource extraction, refining and processing, and transportation. Water is also an integral part of electric-power generation. It is used directly in hydroelectric generation and is also used extensively for cooling and emissions scrubbing in thermoelectric generation. For example, in calendar year 2000, thermoelectric power generation accounted for 39 percent of all freshwater withdrawals in the U.S., roughly equivalent to water withdrawals for irrigated agriculture (withdrawals are water diverted or withdrawn from a surface-water or groundwater source) (Hutson et al., 2004).