Is Natural Gas Bad for the Environment?

Natural gas has often been touted as an important bridge fuel, allowing nations to wean themselves off fossil fuels towards cleaner forms of energy generation. That’s because burning methane, of which natural gas is largely composed, releases approximately half the carbon dioxide into the atmosphere that an equivalent coal-fired power plant would do.

However, methane itself is a potent greenhouse gas, meaning it’s difficult to justify a total transition towards natural gas even in the short term. The fact that so-called “fugitive emissions” (leakages from pipelines, wells and storage facilities) are incredibly difficult to monitor and even more challenging to prevent makes the situation even more complicated.

A double-edged sword

In comparison to coal, the dirtiest form of energy generation still being used on a widespread basis, natural gas certainly offers advantages with regard to its carbon emissions. However, methane can actually be viewed as more damaging to greenhouse gas targets set by bodies such as the EU, since it’s all dependent on what kind of timeline is used for assessing its impact.

Methane persists in the atmosphere for far less time than CO2, but has a greater warming effect while it exists. Taken over a 100-year time period (which is the standard when comparing the two gases), methane is believed to be around 25 times more powerful in exacerbating global warming than CO2. Over a 20-year window, that figure skyrockets up to 86 times more potent. As such, careful consideration is clearly required to assess whether natural gas is worth the trouble.

Focusing on the fugitives

One of the biggest concerns surrounding natural gas use is its propensity to seep out from wells, storage tanks and urban distribution pipelines. Were its use to be ramped up to compensate for a drop-off in coal, the incidence of such fugitive emissions would only increase. Although there are ever more sophisticated methods of measuring methane concentrations in the field, including the use of gas chromatography and laser technology, keeping tabs on it is still a troubling prospect.

This uncertainty is what it makes is so difficult to know whether investing heavily in natural gas technology is a prudent approach to limiting global warming, according to the authors of a new study from MIT on the subject. “In many data sets, a small fraction of point sources contributes disproportionately to overall emissions,” explains Magdalena Klemun, co-author on the paper. “If it were easy to predict where these occur, and if we better understood why, detection and repair programs could become more targeted.”

Different scenarios

For their research, Klemun and her colleague Jessika Trancik looked at what would happen in two different scenarios. In the first, the US replaced all coal power plants with natural gas ones, while in the second, the leap was made straight to cleaner forms of energy generation such as wind, wave and solar power. For each, they stuck by the country’s own purported target of reducing carbon emissions by 32% before 2030.

In outcome one, they found that current natural gas facilities would have to improve their abilities to detect and prevent fugitive emissions of methane by anywhere between 30% and 90% if the target was to be met. On the other hand, switching straight to renewables (while still retaining natural gas as part of the energy mix) would not require any improvement of the existing infrastructure. While not conclusive, the research certainly provides food for thought for policymakers keen to implement natural gas as a bridge fuel.