Study: Natural gas is harmful to the climate than coal and petroleum
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From Benjamin Reuter in energy - 07.23.2014 08:29w


Actually, the race for the energy carrier of the future seems already decided. Will humanity successfully fight against global warming, it must rely on energy sources that work with the power of the sun, wind, water or geothermal Many climate scientists include the nuclear power to this climate-friendly quartet to do so.
It is also certain that the proportion of fossil fuels like coal and oil must drop drastically in the energy supply. With one exception, the natural gas which was still considered as relatively climate-friendly with many experts, because in comparison to coal during combustion, only about half as much CO2. Moreover, natural gas is considered as the perfect complement to support solar and wind power, and is therefore also praised by the federal government repeatedly as a "bridge technology" to the post-fossil fuel era.Overestimated natural gas as a clean energy carrierEven energy companies such as Shell and the Norwegian Statoil present themselves regularly as climate protection, if they refer to their efforts to provide the world with natural gas.
Now, however, spoiled a U.S. professor of history from the clean natural gas. In the U.S., studies of care Robert Howarth of Cornell University in upstate New York for some time sensation. Now that his latest study in the journal Energy Science & Engineering is published ( here in PDF ), could happen in Europe.
Howarth's central thesis: Who looks on methane addition to the greenhouse gas CO2, which provides that natural gas is a major driver for global warming than coal and oil.
For shale and sandstone derived by natural gas fracking the researchers had his results published in 2011. At that time, however, so also Howarth admitted, lacked reliable records. That has changed since then, he believes, and on the data published since 2011, bases its recent study. In addition, there is now also considerations for conventional natural gas.Methane suggests CO2The background is that methane is a 20 - to 100-times stronger greenhouse gas than CO2. The values ​​vary so greatly, because methane only relatively short stays in the atmosphere. The longer the analysis period, so the better cuts from methane in the climate balance.
Looking at the short-term climate impacts, even small amounts of methane escaping into the atmosphere, is at least as strong influence on the climate change have as CO2. Means: the gas has been woefully underestimated in the debate on climate change. The denounces also Howarth.
But the methane is not produced during the combustion (in among other CO2 is produced), but mainly in the production, transport and processing of natural gas.Experts call this upstream and downstream. In his account Howarth also refers to the efficiency with one, is combusted with natural gas compared to coal and oil.
Howard now assumes that escape between 1.7 and eight percent of the natural gas and thus the methane in the promotion and during transport. The result of his comparative statement shows the following graph:
Both for the heat generation in the household (left) and for electricity production (right) cut oil and coal to a consideration of 20 years better than natural gas. The value in orange are tougher CO2 emissions during the combustion. The red bar represents the climate change impact of methane (in CO2 equivalent values).Criticism is programmedHowarth has been strongly criticized for its first study in 2011 by researchers and industry representatives. Once again, the critics will not be long in coming. Despite the research on which Howarth based, it is still controversial how much methane escapes mainly in the production of natural gas. He also sets the efficiency of new natural gas power plants about 20 percent too low and instead takes the values ​​of existing facilities in the United States.
However, should prove his calculations as approximately correct, that means no less than an earthquake to the global energy and climate policy. At one time the coal would acceptable again, and one reason they shut down for environmental reasons before the gas fired power plants no longer existed.
For a final assessment but is much more research is needed, especially with instruments that measure the methane emissions reliably on site. Time so that the experts they finally tackle. Howarth draws meanwhile his own conclusions from the results of his study: he wants to take the same all fossil fuels from the mains.
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Update: Other researchers maintain that both shale gas and conventional gewonnes natural gas in electricity only about half as much greenhouse gas as coal causes (here, the study of April as a PDF )



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