A typical deep shale gas well requires about 5 million gallons of water to drill and complete. By comparison, a 1,000 megawatt coal-fired power plant consumes the same amount of water every 12 hours.
In fact, deep shale is one of the most water-efficient ways to produce energy. The process requires only a fraction of the amount of water used to produce the same amount of power as nuclear, coal, ethanol from corn, or biodiesel from soy energy production.
To protect groundwater both during hydraulic fracturing and throughout the life of the well, up to eight layers of steel casing and cement are used to form a continuous barrier between the well and the surrounding formations.
Fracturing takes place well below 7,000 feet and solid rock separates the shale deposits from shallow groundwater supplies. The distance and the layer of rock both serve as buffers that make contamination from fracturing virtually impossible. Tests are conducted over the life of the well to verify long-term well integrity and protect groundwater. after the hydraulic fracturing process is complete and the well begins to produce natural gas, some of the water used during the fracturing process flows back to the surface.
This water is typically stored temporarily in lined pits or steel tanks until it is either reused in future fracturing jobs, injected into disposal wells permitted and regulated for that purpose, or delivered to water treatment facilities and eventually discharged as surface water.