Natural gas makes for smart transition to low-carbon future

Using natural gas as an energy source is a smart move in the battle against climate change and a good step towards a low-carbon energy future, according to a recent study by a Cornell University professor.

The impact that substituting natural gas for coal and oil has on global warming has been a subject of much debate in the global energy community. In a recent study titled Assessing the Greenhouse Impact of Natural Gas, Lawrence M Cathles, a professor of earth and atmospheric sciences, made the case that while it would be better to replace coal electrical facilities with nuclear plants, wind farms and solar panels, replacing them with natural gas stations would be faster, cheaper and achieve 40 percent of the same benefit. 

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"Gas is a natural transition fuel that could represent the biggest stabilisation wedge available to us," wrote Prof Cathles.

His study, published in the peer-reviewed journal Geochemistry, Geophysics and Geosystems, compared the reduction of greenhouse warming that would result from substituting gas for coal and some oil to the reduction. This could be achieved by substituting with zero-carbon energy sources. The study reviewed the most recent government and industry data on natural gas "leakage rates" during extraction, as well as recently-developed climate models. The study also looked at expanding the use of natural gas as an energy source, and the climate impact of "unconventional" gas drilling methods such as hydraulic fracturing in shale formations.

Some of the key findings included:

• The reduction in CO2 emissions--which result from a transition to natural gas from coal and some oil--remains steady at 40 percent, regardless of the speed of the transition and the effect of climate-regulating forces such as ocean modulation.

• Although some critics of natural gas cite leakage rates of 8 percent or more, recent industry data and a critical examination of Environmental Protection Agency data support a lower estimate of a 1.5 percent leakage rate for both conventional and hydrofractured wells.

• Even at higher leakage rates, using natural gas as a transition fuel to low-carbon energy sources offers more environmental benefits than continuing with the current volumes of coal and oil consumption. This is due to the different rates of decay of carbon dioxide released by burning coal and oil, and methane released during natural gas extraction.

• Using natural gas as a transition fuel supports the push to low-carbon sources by providing a "surge capacity" if needed, or a buffer when solar and wind production wanes.

"The most important message of the calculations reported here is that substituting natural gas for coal and oil is a significant way to reduce greenhouse forcing, regardless of how long the substitution takes," Prof Cathles wrote.

"A faster transition to low-carbon energy sources would decrease greenhouse warming further, but the substitution of natural gas for other fossil fuels is equally beneficial in percentage terms no matter how fast the transition," he noted. 

This article was published in Natural Gas Europe on 16 July. The author is presently co-Leader of the oil and gas thrust of the Cornell KAUST programme and Director of the Cornell Institute for the Study of the Continents.

By: Energy Market Authority (Singapore)