Expertos, Mundo

Estudio sobre ‘Fracking’ de la Universidad de Texas desestima fuga de metano

19 Sep , 2013
Ben Webster - Editor en Medio Ambiente
The Times  

Fracking does not lead to as much leakage of the greenhouse gas methane as had been feared, according to a study which will strengthen the case for exploiting Britain’s reserves of shale gas.

The study, by scientists at the University of Texas, suggests that exploiting natural gas can be an effective way of meeting climate change targets by reducing reliance on coal. The risk of “fugitive emissions” of methane, a far more potent greenhouse gas than carbon dioxide, has been one of the main objections raised by campaigners against fracking.

David Cameron said last month that shale gas would cut energy bills, and pointed out that, in the US, where more than 10,000 fracking wells open up each year, gas prices are substantially lower than in Britain. However, Sir David King, the Government’s former chief scientific adviser, has argued that there could be severe environmental consequences from fracking, and that it will not be the same “game changer” in Britain as it has been in the US.

The study, published in Proceedings of the National Academy of Sciences, involved taking direct measurements of methane emissions from 150 natural gas production sites in the US containing 489 hydraulically fractured wells. It found that, during the process of extracting natural gas from the ground, total leakage at the sites was 0.42 per cent of all the gas produced — slightly less than the 0.47 per cent which the US Environmental Protection Agency suggested in 2011 was the national average.

The study did not consider other potential downsides of fracking, such as water and air pollution, and concerns about increased traffic and noise in otherwise tranquil countryside. The study authors said they had controlled how the research was done and how the wells were chosen.

Robert Howarth, of Cornell University, one of the scientists who first raised concerns bout
methane leaks, described the results as “good news” but said they might represent a “best-case scenario”.

He said it showed the industry was capable of fracking with very low emissions, “but they very often do not do so. They do better when they know they are being carefully watched.” He said more research was needed to explain why some studies have found high rates of leaking methane and others have not.

Gabrielle Petron, a methane monitoring scientist for the National Oceanic and Atmospheric Administration, suggested that the study might not have included the worst sites for leakage.

She said: “Even very high-quality measurements cannot overcome the small number of operations or sites measured.”

Ira Leifer, a scientist at the University of California, Santa Barbara who has measured methane leaks across the US, said companies might steer scientists away from sites where there were big leaks.

Ralph Cicerone, president of the National Academy of Sciences, and an atmospheric scientist who has researched methane, dismissed concerns that the industry’s funding of the report could have influenced its results.

He said the authors were “some of the very best experts around the country. It doesn’t matter who is paying these people. They’re going to give you the straight scoop.” A spokesman for the Department of Energy and Climate Change said: “We welcome this report, as it supports our approach that, wherever shale gas is exploited, it must be done reducing the environmental and safety risk to as low as reasonably practicable.”

The study was funded largely by oil and gas companies but carried out by a team of independent scientists.

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