Natural gas is often called the bridge fuel to a cleaner energy future, a premise that enabled the natural gas boom in the U.S. over the last decade, specifically a boom in controversial drilling process called fracking.
That fracked natural gas improved the United States is undeniable. Putting aside the effect on local water supplies (which may be considerable) the economic impact has been tremendous. The boom has allowed the U.S. to have cheap energy and reduce its carbon emissions, which is an excellent combination. It’s time we accepted this, because the main alternative is much worse: coal. Coal is enemy number one. Compared to that, natural gas–even fracked natural gas–is better.
Having said that, there are reasons to doubt fracked gas is the way forward long-term, both for the U.S. and the world in general. Although natural gas is often cited as a bridge fuel, the question is whether it continues to be a net positive, especially for the countries that are now trying to develop their unconventional gas resources. Is natural gas a “bridge” to a low-carbon future or an ill-considered, unambitious diversion?
A new report from the Stockholm Environment Institute answers that question. And it says while natural gas has a lot of potential to reduce global carbon emissions compared to coal, the extent is limited by practice. It depends on exactly how natural gas is mined and stored, how it’s used, and what its price is relative to other forms of energy.
The paper was produced for the New Climate Economy, an initiative of seven countries (Colombia, Ethiopia, Indonesia, Norway, South Korea, Sweden and the United Kingdom) looking at how to maintain economic growth while curbing climate change. “Recent U.S. experience was unique in terms of delivering significant benefits to both the climate and the economy,” it says. “Despite such a best-case scenario, current research suggests that a more enduring climate-economy ‘win-win’ based on increased natural gas supply is far from guaranteed.”
Its less than full-bloodied endorsement of natural gas is prompted by three factors: “substitution,” methane leakage and “scale effects.”
First, the carbon benefits of gas depend on how much is used where it can have most impact. That means replacing coal for electricity generation (where the reduction could be 40% to 50%) rather than heating homes and buildings where the reduction could be as little as 15%.
Second, we have to worry about methane leakage from gas wells, especially as the sheer number of holes increases the chances of methane escaping. Methane is 20 times more potent as a greenhouse gas than carbon dioxide. Indeed, some scientists say fugitive emissions make gas no better than coal. A study in Science last year of 20 years of previously published research found emissions well beyond government estimates. It said the benefits of switching from coal to gas would be offset by methane leakage.
Third, some of the carbon benefits of switching to gas are lost to “scale effects”–i.e. where an abundance of gas leads to lower prices and, therefore, a more carefree attitude to energy efficiency. Several studies have shown “that more abundant, inexpensive gas supplies . . . lead to increased energy consumption, partly or fully offsetting the [greenhouse gas] benefits from substitution of other fuels,” the report says.
In essence, the report puts the record straight about natural gas’s benefits to the U.S. economy over the last decade (very serious water issues aside), but it cautions against repeating the trick globally or for too long in the U.S. Natural gas has a lot of potential to cut carbon emissions, but exactly how much will depend on how it’s mined and how it’s used. Given experience, it may end up being a bridge that doesn’t go very far.