You could describe my job as an environmental engineer as getting clean water to people and dirty water away from people. This takes some energy, and so it can be expensive. We try to take advantage of the fact that water goes downhill - especially on the Columbia and Snake rivers, from which Pacific Northwesterners get the majority of our energy (followed by coal and natural gas). Some quick Google searching turns up other emerging technologies to extract energy from water, such as ocean thermal energy conversion. And a new buzz word around the environmental consulting word (along with sustainability) is The Energy-Water Nexus. We're getting smarter about this stuff all the time.
Wikipedia defines the water-energy nexus as “the relationship between how much water is evaporated to generate and transmit energy, and how much energy it takes to collect, clean, move, store, and dispose of water.” “The Carbon Efficient City,” by A.P. Hurd, the Water Efficiency online journal and others that are for aligning water resource management with climate change action cite strategies such as: public and private investments in water conservation and recycling; increasing the value of a gallon of water in the market; and providing consumer choices that reduce our individual water footprints.
But don’t forget about agriculture. Agriculture uses much more freshwater than drinking water and other domestic needs– 70 percent is often the number cited. Running irrigation equipment, creating and transporting fertilizers and pesticides all require water and energy. For local urban agriculture, rain barrels can provide an alternative to using the City drinking water that takes energy to produce and distribute.
Agriculture’s efficient water and energy use directly impacts food security, especially with the uncertainty of climate change and the price of fuel. So it seems reasonable to prioritize water use efficiency in agriculture, as well as in domestic water, particularly in developing nations. The Huffington Post Water Blog recently explored this global issue, and calls on the U.S. to take a leading role in the solutions, which could include growing specific crops to make the best use of water and energy resources to meet global and local food needs. The same perspective and strategies probably also apply to us locally here in Seattle, even with our relative abundance of water.