Natural gas is just another dirty fossil fuel on the road to disastrous climate change. Natural gas is a cleaner alternative to oil and coal – and a “bridge” fuel to a renewable energy economy.

Extracting natural gas through fracking is good for the economy and makes us less dependent on Middle East oil. Fracking wrecks the environment and causes earthquakes.

Wherever you turn, there are diverging opinions on natural gas. In this post, we review a few of the main pros and cons of this widely used fuel, which is an increasing source of energy for electricity generation and a major energy commodity for heating and cooking.

Pros

Natural gas is abundant and a major source of energy.

The United States is awash in natural gas, with enough on tap to last the rest of this century given 2013 consumption rates, according to the U.S. Energy Information Administration.

Meanwhile, natural gas production reached a record high level of 79 billion cubic feet per day in 2015, and it’s expected to soon surpass coal in the mix of fuel used for U.S. power generation. In 2015, natural gas accounted for about one-third of electricity production in the U.S. – equal to coal and ahead of nuclear power, which accounted for almost one-fifth.

As of January 1, 2013, there were about 2,276 trillion cubic feet of technically recoverable “dry,” or consumer-grade, natural gas resources in the U.S., according to EIA.

As reported widely, natural gas production has been booming in the U.S., with a 35-percent increase between 2005 and 2013.

Meanwhile, total proved reserves of gross natural gas worldwide totaled 6,846 trillion cubic feet.

A relatively clean fossil fuel, a ‘bridge’ fuel

“Relative” is the operative word here. Compared with coal, natural gas emits half the CO2 when it’s burned.

But unburned, natural gas (which is mostly methane) is about 25 times more potent a greenhouse gas than CO2 over a 100-year period (more on this below, under “Cons”).

Because it’s relatively clean compared with other fossil fuels, proponents champion natural gas as a “bridge” fuel to support a growing renewable energy economy, supplementing intermittent solar and wind power.

Natural gas is relatively cheap.

The cost of natural gas in March of this year fell to its lowest levels since 1998 – to $1.57 per million Btu according to “Henry Hub” spot prices.

However, in recent months spot prices have been rising. EIA reported the Henry Hub spot price at $2.93 per million Btu as of June 29. Comparing fuel prices can be tricky, and energy costs vary by region.

However, a comparison of current average prices for fossil fuel for electricity generation, by state, can be found at EIA.

On July 1, the NYMEX West Texas Intermediate Crude Oil Price was $48.99 per barrel. That’s equal to $8.45 per million Btus generated, far more expensive than the current price of natural gas

Some reasons why average natural gas prices are relatively low: high production and storage levels, and this past winter’s El Niño depressed the demand for natural gas for heating.

There is some indication that low prices for natural gas and for oil may endure, in part because of the spread of extraction technology improvements globally.

But that view isn’t universal: EIA in January expressed a contrary short-term view and projected increasing natural gas prices over the next two years.

Natural gas industry – a big employer.

Jobs in renewable energy are growing while those in conventional oil and gas sectors are declining.

Nevertheless, the natural gas industry in the U.S. supports 2.8 million jobs, according to the America’s Natural Gas Alliance.

And from 2007 through 2012, employment in the oil and natural gas industries grew by more than 162,000 jobs, a 40-percent increase, according to EIA.

A significant player in making renewable energy viable

Consider natural gas a “bridge” fuel for a growing renewable energy economy. In its 2015 report, “Pathways to Decarbonization: Natural Gas and Renewable Energy,” the Joint Institute for Strategic Analysis wrote that natural gas and renewable energy “can help contribute to a low-carbon, resilient, and reliable electrical grid by diversifying the electricity mix and hedging risk associated with market and policy uncertainties.”

Meanwhile, EIA projects that natural gas and renewables will account for growing shares of electricity generation. That’s unlikely to happen uniformly, however: In California, the current oversupply of natural gas and a boom in solar, wind, and other renewable energy sectors “has depressed power prices and threatened the viability of natural gas plants,” Reuters reported in early June.

Cons

Natural gas is itself a powerful greenhouse gas.

Methane is a powerful greenhouse gas, although it doesn’t remain in the atmosphere as long as CO2. It’s the second-most prevalent greenhouse gas, behind CO2, and in 2014 it accounted for about 11 percent of all greenhouse gas emissions from human activities, according to EPA. Globally, more than 60 percent of total methane emissions come from human activities, and of that amount 33 percent come from emissions from the natural gas and petroleum industries.

Pound for pound, EPA reports, the comparative impact of methane on climate change is more than 25 times greater than CO2 over a 100-year period and about 84 times more potent than CO2 over a 20-year period. (But it’s important to remember that far more CO2 than methane is emitted into the atmosphere, and CO2 lasts far longer in the atmosphere.)

Natural gas a nonrenewable resource

A no-brainer here: Natural gas, a fossil fuel, is not a renewable energy resource.

In a 2014 news article in The New York Times, environmental and climate change activist Bill McKibben argued that the nation should stop relying on natural gas as a supplement to renewable energy. “It’s time to stop searching for a bridge and simply take the leap,” he said.

Leaks and flaring lead to large GHG emissions

From late October to mid-February, about 100,000 tons of methane entered the atmosphere from a Southern California natural gas well blowout at the Aliso Canyon storage facility (see here, here, and here). It is believed to have been the worst accidental methane gas leak in U.S history, and a powerful example of the many unintended natural gas emissions at wells and along transmission pipelines in the natural gas industry.

“Failures in machinery as vast as the U.S. natural gas system are to be expected – more than 300,000 miles of pipeline run across the country,” Time magazine reported in late February.

A 2014 Stanford University study reported on by PBS News Hour estimates that methane emissions may be 25 to 75 percent higher than what EPA projects.

Another study published last August found that natural gas facilities lose about 100 billion cubic feet of natural gas every year – about eight times what EPA estimates, the PBS News Hour reported (also see here).

Natural gas leaks are considered a national problem, in which many little ongoing leaks add up to a lot. Authors of a 2013 study in the Proceedings of the National Academy of Sciences suggested that human-caused emissions of methane could be underestimated by 50 percent.

Fracking’s real environmental concerns.

Hydraulic fracturing, or fracking, has unearthed huge amounts of oil and natural gas across the U.S. that previously were inaccessible economically from shale, sandstone and carbonate formations such as limestone.

Key regions of shale, which contain organic material that have generated oil and natural gas, include the Barnett Shale formation in Texas and the Marcellus Shale formation in the eastern U.S. More than 30 states have shale formations.

During fracking, a mixture of water, sand, and chemicals is injected into a well at high pressures, fracturing rock far beneath the surface and releasing the gas trapped inside. The gas then flows up toward the surface and out of the head of a well.

Fracking poses substantial environmental concerns. Fracking requires huge amounts of water, often transported to remote locations. There are also concerns over the chemicals used in the mixture injected into wells, including the possibility of groundwater contamination. A complicating factor: The fossil fuel industry has been reluctant to disclose which chemicals are used, citing proprietary considerations. (The website FracFocus is a repository of information on known chemicals used in fracking around the country.)

Finally, there are worries that fracking may cause regional earthquakes, an issue that has attracted substantial national attention and concern.

The U.S. Geological Survey has said fracking causes extremely small earthquakes, nearly always too small to cause damage. In 2015, scientists at Stanford University found that a spate of ongoing earthquakes in Oklahoma related to fracking was more due to the disposal of wastewater deep underground after fracking than to fracking itself. So those quakes may be best understood as a by-product of the fracking process, rather than as a direct component of fracking.

For a closer look at fracking, see “Pros and cons of fracking.”

Aging infrastructure poses ongoing dangers

It’s no secret that much of the infrastructure for the transport and storage of natural gas is aging and vulnerable to leaks and explosions.

In 2010, a massive gas pipeline explosion in San Bruno, California, just south of San Francisco, leveled a neighborhood and killed eight people. The National Transportation Safety Board concluded that the cause was a defective seam weld in a pipeline segment. Meanwhile, decaying pipes in New York City have been called a “ticking time bomb.”

And then there was the recent four-month leak of methane gas at the Aliso Canyon storage facility north of Los Angeles. Authors of a study in the journal Science estimate the leak caused the equivalent of annual greenhouse gas emissions from 572,000 cars (see here and here).

A report from Inside Energy in December discussed some of the challenges of an aging natural gas infrastructure, including 1.6 million miles of natural gas pipelines that connect wells to homes – a third of those pipelines built before 1970.

More on natural gas
Natural Gas Infrastructure Implications of Increased Demand from the Electric Power Sector
National Gas: Abundance of Supply and Debate
The Natural Gas Gamble: A Risky Bet on America’s Clean Energy Future
The Dirty ‘Clean Fuel’: Why Natural Gas Out-Pollutes Coal (Op-Ed)
China’s Cheap Coal Slows Switch to Natural Gas
Most Natural Gas Production Growth Is Expected to Come from Shale Gas and Tight Oil Plays