Water Requirements of Fracking

Our society and, indeed, the global society are in some turmoil now because of the adoption of widespread hydraulic fracturing in the US. Fracking is not new, having been used in one form or another since about the 1950s. However, the use of horizontal drilling with increased pressures and volumes of fracking fluid, the industry has expanded enormously. Water use for fracking and extraction has become a major public concern. This is especially true in the West where riparian rights have been a cause of serious confrontations over the past two centuries and are about to expand in this century as states begin to renegotiate contracts for water sharing. 

We have examined in Parts I and II, the health and environmental consequences of fracking. Let us look at the water requirements for fracking and the potential for surface-water and groundwater contamination.

Fracturing and horizontal drilling are water-intensive processes. Jackson et al. (Annu. Rev. Environ. Resour. 2014. 39:327-62) in an informative article, state that fracking requires 2-20 million gallons for a single well and an additional 25% for drilling, extraction, and mining. Although this is a large amount, they point out that, across Texas, the amount of water used for fracking is about 1% of the total water used in Texas per year. This can be misleading, since water requirements can vary considerably from one location to another depending upon the technology required to release and extract the product. So, even if the total amount may be sustainable, it may not be in regions where the requirement for extraction is high. This was the case in the Marcellus Shale in Pennsylvania where too much water was taken from streams locally that created problems for residents in the area. 

It also is possible to normalize the amounts of water used to the amount of energy it extracts and to look at water intensity (amounts used per units of energy obtained) for various sources of energy. The latter is more important to those interested in the societal and environmental issues in energy extraction. When the comparison is made (Jackson et al., Table 2, pg. 336), “it is clear that shale-gas extraction and processing are less water intensive than most other forms of energy extraction except conventional natural gas and, especially, renewables such as wind and solar photovoltaics that consume almost no water”(emphasis mine). The most water intensive processes are corn ethanol. When unirrigated, it requires as much or more water than any other source of energy; when irrigated, the water required increases by 30-fold.

 When examined on a basis of water consumption per intensity of electricity generated, solar-photovoltaic and wind are by far the most efficient of any source of energy. Natural gas plants consume about half or one-third of the water that a nuclear or pulverized coal power plant does.  Unirrigated corn is among the worst in efficiency and irrigated corn remains the most inefficient by a wide margin. It is difficult to make any case for using corn as a source for fuel, whether it be from the perspective of water use, cost of the material, or its impact on food costs globally. The authors also point out that as refracturing of wells becomes more common, the water intensity will rise. 

Renewable sources of wind or photovoltaics use 100 times less water for electricity generation than all other sources presented.