Carbon Footprinting for Water Utilities: Effective Energy Management to Save Money and Decrease Your Greenhouse Gas Emissions!

Over the past several years, energy expenditures have taken an increasing percentage of the average water utility's budget. At the same time, society is becoming increasing concerned about global warming and greenhouse gas emissions (GHGe). Customers and regulators alike are looking to water utilities to be good environmental stewards by minimizing energy use and GHGe/carbon footprint.Three years ago, American Water responded to this growing concern by developing the tools necessary to measure, and then manage American Water's energy and carbon intensity; that is the energy and carbon dioxide equivalent (CO2e) per unit of water produced, respectively. These efforts have provided the tools needed to effectively measure and manage American Water's energy and carbon footprints today, and to prepare for future mandatory carbon limits or Cap & Trade regulations.This case study will provide a general discussion energy use in water utilities, trends in that energy use, and opportunities to minimize energy use and GHGe/carbon emissions. The case study will detail steps a utility can take to:Measure energy use, energy purchases and process emissions;Calculate its carbon emissions by conducting a GHGe Inventory;Analyze the Inventory results using meaningful measures and metrics.It will conclude by presenting selected results from American Water's last three years of efforts to develop such a program; results that are generally representative of the water industry as a whole. The results provide conclusive evidence that energy used in pumping is responsible for the vast majority (about 90%) of GHGe from U.S. water utilities; a finding supported by the literature.