Researchers have investigated the impacts of certain gas ‘fracking’ techniques, and found that they can be more environmentally-friendly than wind or solar plants.

The study suggests that greenhouse gas emissions from shale gas are comparable to conventional natural gas, but the controversial energy source actually fairs better than renewable sources on some environmental impacts.

Researchers in the UK compared shale gas to other fossil-fuel alternatives, such as conventional natural gas and coal, as well as low-carbon options, including nuclear, offshore wind and solar power.

The comparison used estimates of each system’s life cycle environmental impacts “from ‘cradle to grave’”.

The team looked at 11 different impacts from the extraction of shale gas using hydraulic fracturing as well as from its processing and use for generating electricity.

The results suggested that the average emissions of greenhouse gases from shale gas over its entire life cycle are about 460 grams of carbon dioxide-equivalent per kilowatt-hour of electricity generated.

This, the authors say, is comparable to the emissions from conventional natural gas. For most of the other life-cycle environmental impacts considered by the team, shale gas was also comparable to conventional natural gas.

But the study also found that shale gas was better than offshore wind and solar for four out of 11 impacts: depletion of natural resources, toxicity to humans, as well as the impact on freshwater and marine organisms. Additionally, shale gas was better than solar (but not wind) for ozone layer depletion and eutrophication (the effect of nutrients such as phosphates, on natural ecosystems).

On the other hand, shale gas was worse than coal for three impacts: ozone layer depletion, summer smog and terrestrial eco-toxicity.

“Some of the impacts of solar power are actually relatively high, so it is not a complete surprise that shale gas is better in a few cases,” University of Manchester’s Professor Adisa Azapagic says.

“This is mainly because manufacturing solar panels is very energy and resource-intensive.

“However, our research shows that the environmental impacts of shale gas can vary widely, depending on the assumptions for various parameters, including the composition and volume of the fracking fluid used, disposal routes for the drilling waste and the amount of shale gas that can be recovered from a well.”

“Whether shale gas is an environmentally sound option depends on the perceived importance of different environmental impacts and the regulatory structure under which shale gas operates.

Study co-author Dr Laurence Stamford said: “Appropriate regulation should introduce stringent controls on the emissions from shale gas extraction and disposal of drilling waste. It should also discourage extraction from sites where there is little shale gas in order to avoid the high emissions associated with a low-output well.

“If shale gas is extracted under tight regulations and is reasonably cheap, there is no obvious reason, as yet, why it should not make some contribution to our energy mix,” he continued.

“However, regulation should also ensure that investment in sustainable technologies is not reduced at the expense of shale gas.”

A copy of the report is accessible here.