Water Requirements of Shale Production
The drilling and hydraulic fracturing of a horizontal shale gas well on average requires 3.5 million gallons of water. This volume of water is equivalent to 5 and ½ Olympic size swimming pools. Water for drilling and fracturing shale gas frequently comes from surface water bodies, but can also come from ground water, private water sources, municipal water, and re-used produced water. Most of the producing shale gas basins are located in areas with moderate to high levels of annual precipitation, however with other regional water demands and seasonal variation in precipitation, the needs of shale gas development must be met in careful balance with regional needs for water.
Nevertheless, when compared with other major forms of energy production, production of shale requires only a fraction of the water required to produce energy from coal and nuclear sources. Producing natural gas from shale requires about 0.6 to 1.8 gallons of water for every million Btu (MMBtu), less than 15 percent of the water needed to produce the equivalent amount of energy from coal. (Chesapeake Energy, Media Resources: Hydraulic Fracturing Fact Sheet, 2009.) For comparison, the consumption of fresh water for hydro-electrical generation in the Susquehanna River Basin alone is nearly 150 million gallons per day, while the projected total demand for peak Marcellus Shale activity in the same area is relatively small at 8.4 million gallons per day.
A related aspect of water use for shale production is that natural gas operators need water as drilling activity occurs, requiring that the water be procured over a relatively short period of time, which environmental groups point out could impact aquatic life during periods of low stream flow. Water used in the drilling and fracturing process must be properly permitted and paid for, which natural gas operators say helps to ensure that water used to produce shale gas does not interfere with the available supply for other users.
Developing shale gas is consistent with a sustainable U.S. energy/water strategy by making a positive energy and economic contribution at a relatively low cost to water supply.