A Spatiotemporal Exploration of Water Consumption Changes Resulting from the Coal-to-Gas Transition in Pennsylvania

During the early stages of Pennsylvania's coal-to-gas transition, extraction and generation of coal and natural gas contributed to a yearly 2.6–8.4% increase in the state's water consumption. Although some areas experienced no change in water consumption, others experienced large decreases or increases. Consumption variations depended on available natural gas resources and pre-existing power-generating infrastructure. This analysis estimates monthly water consumption associated with fuel extraction and power generation within Pennsylvania watersheds between 2009 and 2012. It also provides the first comprehensive representation of changing water consumption patterns associated with the state's coal-to-gas transition at the sub-basin level. The analysis shows that water consumption for natural gas energy extraction and production increased throughout the period, while for coal extraction and production it decreased. Water use for natural gas generation increased 67%, particularly in the Philadelphia and Pittsburg areas; water use for hydraulic fracturing increased nine fold in southwest and northeast Pennsylvania. By contrast, water use for coal extraction and production decreased 13%. In some areas, increased water consumption resulting from hydraulic fracturing was offset by decreased water consumption for power generation as plants switched from coal to natural gas. An interactive map and chart highlighting the changes can be accessed at www.nicholasinstitute.duke.edu/hydraulic-fracturing. These findings indicate the importance of considering the implications of energy production and generation choices in the context of both energy extraction and production sectors and of doing so at smaller-than-state-level scale.