There is a close connection, or nexus , between energy and water:
It takes a significant amount of water to create energy. Water is used to cool steam electric power plants – fueled by coal, oil, natural gas and nuclear power – and is required to generate hydropower. Water is also used in great quantities during fuel extraction, refining and production.
It takes a significant amount of energy to extract, move and treat water for drinking and irrigation . It is used in the collection, treatment and disposal of wastewater. Energy is also consumed when water is used by households and industry, especially through heating and cooling.
A shortage of water can inhibit energy production since power plants in the United States withdraw 143 billion gallons of fresh water every day, more than the amount withdrawn for irrigation and three times as much as is used for public water supplies. A shortage of water readily available to a power plant can also result in more energy being used to pump water from faraway sources or from deeper wells.
Water is essential to the United States' ability to grow food and produce electricity. Current agricultural policy relies on a plentiful supply of water for irrigation and a plentiful supply of the fossil fuels used for fertilizer-intensive crops and the machinery used to raise them. Changes in global precipitation patterns due to climate change threaten the balance of water available for agriculture. At the same times fossil fuels are becoming a less viable source of energy, due to depletion, cost, and environmental damage.
Water and energy policy, planning and management must be integrated to encourage conservation, motivate innovation and ensure sustainable use of water and energy. End users, such as businesses and households, also have an important role to play. By reducing the amount of water they consume, end users conserve not just water but energy, too. This in turn can save money on utility bills.