Business Green staff reported that US scientists have once again warned large amounts of methane could be leaking from new onshore gas drilling projects, challenging claims the fuel can offer a lower emissions alternative to coal.
According to preliminary results published in Nature by a team comprising researchers at the National Oceanic and Atmospheric Administration and the University of Colorado in Boulder, around 9% of the potent greenhouse gas methane produced by a gas field in Utah was shown to be escaping into the atmosphere.
It follows a study published by the same scientists in February last year suggesting up to 4% losses of methane at a field near Denver.
The US has seen energy prices tumble as a surge in onshore shale gas production has allowed energy generators to switch from coal to gas. The gas industry has argued that the move has helped to cut US greenhouse gas emissions, as gas is significantly less carbon intensive than coal.
But while research published in April by campaign group Environmental Defense Fund and Princeton University suggested shifting to natural gas would have immediate climate benefits especially if replacing old coal plants these would only be realized if the cumulative methane leakage rate from shale gas projects is below 3.2%.
Furthermore, the methodology for calculating leakage has been disputed by Mr Michael Levi, an energy analyst at the Council on Foreign Relations in New York, who published a peer reviewed comment presenting an alternative interpretation of the data that would align overall leakage rates with previous estimates.
However, the scientists said that if leakage rates across the country are similar to those quoted for the projects in Denver and Utah, much of the climate benefits from using gas instead of coal to generate power could be offset by methane emissions.
NOAA scientists and industry partners are now analyzing emissions from the production, gathering, processing, long distance transmission and local distribution of natural gas, as well as collecting field data from across the US, and are expected to submit an initial study for publication by next month.
Source - www.businessgreen.com