With the advent of fracking, shale gas is all the rage these days. Shale gas, which is natural gas that is retrieved from shale rock formations, has the potential to be a game changer for the United States economically, and there is also a chance that natural gas could lower our net emissions. The problem is that we don't precisely know how dirty natural gas is, and at the very least, we know it's half as dirty as coal.
We know that the burning of natural gas produces 1,135 pounds of carbon dioxide per MWh of electricity generated. Compared to solar, wind and nuclear energy, which all produce 0.00 pounds of carbon dioxide per MWh produced, natural gas is an incredibly dirty source of electricity. By comparison, coal produces 2,249 pounds of carbon dioxide per MWh of electricity generated.
With this information in hand, people often conclude that natural gas is cleaner than coal, and therefore it is an ideal transition fuel. There are three problems with this conclusion.
First, natural gas produces emissions when it is burned. It also produces methane, a far worse greenhouse gas than carbon dioxide, during the extraction process. According to scientists in the documentary, Gasland Part 2, five percent of natural gas wells fail immediately, and the majority of wells fail over time.
Second, natural gas is a temporary replacement fuel for coal that will only continue to replace coal when it remains cheap. If we do not replace our base load with wind, solar or nuclear, then coal will simply replace natural gas when natural gas prices increase. And natural gas prices will increase over the next few years, when we start exporting it to global markets where the stuff is pricier.
Third, even as a replacement, and even if the methane leakages are not as bad as assumed, natural gas is still dirtier than clean sources. "Half as bad as coal" is simply not good enough when it comes to reducing our carbon footprint.
There are two massive ongoing studies to measure the environmental impact of shale gas fracking. The Environmental Defense Fund is coordinating 85 academic researchers to measure the methane leakage from shale gas extraction. And the EPA is studying the contamination effects of shale gas fracking on water supplies. Both studies are set to come out in the fourth quarter of 2014. In the meantime, we suggest a moratorium on new drilling until we have all of the facts.