Everyone has an opinion on fracking, but questions do remain as to what kind of threat it is to biodiversity, which includes pollution from toxic chemicals, the building of well pads and pipelines, and changes to wetlands.
New research, however, goes on to review the biodiversity challenges brought on by fracking.
“Shale gas has engendered a great deal of controversy, largely because of its impact on human health, but effects on biological diversity and resources have scarcely been addressed in the public debate,” said study author Erik Kiviat in his report in the Annals of the New York Academy of Sciences.
The controversial method of mining shale gas, covers a good chunk of Pennsylvania, covering up to 280,000 km² of the Appalachian Basin.
“This study indicated a wide range of potential impacts, some of which could be severe, including salinization of soils and surface waters and fragmentation of forests. The degree of industrialization of shale gas landscapes, and the 285,000 km² extent of the Marcellus and Utica shale gas region alone, should require great caution regarding impacts on biodiversity.”
Meanwhile, the value of a fuel’s long-term usefulness and viability comes through its energy return on investment; the comparison between the eventual fuel and the energy invested to create it. A energy return on investment (EROI) study published in the Journal of Industrial Ecology finds that shale gas has a return value which is close to coal.
In the U.S., gas emanates comes from horizontal, hydraulically fractured wells in the Marcellus Shale of Pennsylvania. The study compares the total input energy with the energy expected to be available to end users.
The analysis indicates the EROI ratio of a typical well is likely between 64:1 and 112:1, with a mean of approximately 85:1. This range assumes an estimated ultimate recovery (EUR) of 3.0 billion cubic feet per well. This is similar to the EUR of coal, which falls between 50:1 and 85:1.
“Our analysis indicates that gas can be extracted from shale efficiently, from an energy perspective. The energy return on (energy) investment ratio (EROI) does seem to be at least as favorable as coal,” said lead author Mike Aucott. “However, a comparison with coal is difficult. There appears to be large amounts of coal still available. Estimates of the amount of gas available from the shale plays vary widely. It is not clear yet whether there is anywhere near enough to rival coal over the long haul.”
“There are concerns about water pollution and other environmental impacts associated with shale gas production,” Aucott said. “With the assumption that these can be managed, and that production quantities remain consistent with initial production data, the favorable EROI suggests that shale gas will be a viable energy source for quite some time.”