AN ENERGY APPETITE OF U.S. WATER SYSTEMS HOW MUCH ENERGY DOES IT TAKE TO SUPPLY OUR WATER?

“If you think it's simple, then you have misunderstood the problem. ” [1] This paper reports a new method to estimate energy used in water supply and return phases of the water cycle. An example is a composite case for energy used in water systems of the United States (U.S.) using data from the U.S. Geological Survey (USGS). The new method is innovatively simple: it avoids complexities of data-intensive, bottom-up models, often used to map water networks. This method helps to prioritize how to improve energy efficiency in water systems. The method uses a top-down approach requiring limited system data, and relying on a transparent computation of energy. The method applies to standalone or composite systems. It applies to small-scale, single-user systems, to large water supply/return networks, or to summations of data for classes of systems whether simple or complex, and whether interconnected or not. The reported example shows transport could account for about 95 percent of U.S. water systems' energy use. Energy use for transport among different water- sectors ranged from roughly 80 percent to nearly 100 percent of total sectoral energy demand. Contrasting that generalization, specific data for standalone systems would show when energy demand depends, for example, more on treatment needed to meet quality standards