White Paper: The Carbon Footprint Of Water

By Bevan Griffiths-Sattenspiel and Wendy Wilson

The decisions being made today regarding the management of water and energy resources will profoundly affect our economic and environmental future. Climate change and other stresses are limiting the availability of clean water and cheap energy. A large amount of energy is expended to supply, treat and use water, meaning that water-oriented strategies can result in significant reductions in energy use and greenhouse gas emissions. This report explores the energy and carbon emissions embedded in the nation's water supplies. We have developed a baseline estimate of water-related energy use in the United States, as well as a comparative overview of the energy embedded in different water supplies and end-uses. We include numerous examples of how water management strategies can protect our freshwater resources while reducing energy and carbon emissions. This information is intended to help river and watershed groups, policy makers and water managers understand the magnitude of water related energy use and evaluate the potential to reduce carbon emissions through water conservation, efficiency, reuse and low impact development strategies.

Through our analysis of primary and secondary research, we estimate that U.S. water-related energy use is at least 521 million MWh a year — equivalent to 13% of the nation's electricity consumption. While this appears to be a conservative estimate of water-related energy use, our findings suggest that the carbon footprint currently associated with moving, treating and heating water in the U.S. is at least 290 million metric tons a year. The CO2 embedded in the nation's water represents 5% of all U.S. carbon emissions and is equivalent to the emissions of over 62 coal fired power plants.

Most significantly, the carbon footprint of our water use is likely growing for several reasons. Climate change is predicted to have numerous adverse affects on freshwater resources, rendering many available water supplies far less reliable. With water demand growing and many local, low-energy supplies already tapped, water providers are increasingly looking to more remote or alternative water sources that often carry a far greater energy and carbon cost than existing supplies. Furthermore, the adoption of higher water treatment standards at the state and federal levels will increase the energy and carbon costs of treating our water and wastewater.

The link between water and energy presents the climate change community with a valuable opportunity to better manage two of our most valuable resources. As the U.S. struggles to reduce its carbon emissions in response to global warming, investments in water conservation, efficiency, reuse and LID are among the largest and most cost-effective energy and carbon reduction strategies available. Furthermore, water is perhaps the most vital ecosystem service that our natural environment provides. As the inevitable impacts of climate change become evident, our freshwater resources and the ecosystems they support will become respectively less reliable and resilient. Smart water policies allow us to mitigate the worst aspects of global warming today, while the consequent improvements in water quantity and river health will provide a critical buffer as humanity and nature adapt to the climate of tomorrow.

Published by © River Network