By John Parnell
Both sides of the shale gas debate have scored a point with the release of two new pieces of research.
New evidence presented jointly by the National Oceanic and Atmospheric Administration (NOAA) and the University of Boulder, estimates methane leaks from shale gas drill sites total around 9% of the total gas production.
Previous estimates of 4% caused controversy initially but the same team has now found higher leakage rates at other drill sites.
Methane is a potent greenhouse gas that warms the atmosphere 72 times greater than CO2 over a 20 year period.
When leaks pass 2% the emission reduction benefits of using shale gas rather than coal to generate electricity are cancelled out.
The shale gas boom in the US reduced its domestic emissions but has created local environmental tensions. (Source: Flickr/SkyTruth)
Hydraulic fracturing pumps a mix of sand, water and chemicals into shale rock formations to open fissures and release the trapped gas.
Claims that this technique can pollute water sources have led to many US states, including New York to ban the practice.
However, a leaked report from the New York Health Department appears to clear the practice.
The report, written in February of 2012, says “significant adverse impacts on human health are not expected from routine HVHF (hydro fracking) operations.” Shale gas advocates called for the ban to be immediately lifted.
However a statement from the state Department of Environmental Conservation said this was “outdated” and “does not reflect final DEC policy”.
The issue of methane leaks is also hotly contested with the most recent study at one end of the spectrum at 9% and another paper published in November last year putting its own estimates at less than 1%.
The US has reduced its emissions by using its shale gas reserves to produce electricity instead of coal. Critics question this claim as the coal has instead been exported to other markets.