Can Shifting from Coal-fired Power Plants to Natural Gas Help Tackle Global Warming?

Ask a Scientist - October 2012

N. Mitchell from Salt Lake City, UT, asks “It seems to me that shifting from coal-fired power plants to generating electricity from natural gas can be an important interim energy strategy for tackling global warming. What does UCS think?” Senior Staff Writer Seth Shulman of Pulse conducted a Q & A session with Rachel Cleetus, Senior Climate Economist at the Union of Concerned Scientists, who offers this response:

UCS research shows that many coal-fired power plants around the country are being retired, and an increasing number are candidates for closure, because they are becoming too expensive to operate compared to cleaner alternatives.  Natural  gas, renewable sources of energy, and energy efficiency measures are stepping up to replace coal because they make more economic sense. That development is good news for U.S. carbon dioxide emissions which are now at a 20-year low, as well as emissions of other harmful pollutants like mercury, sulfur dioxide, and nitrogen oxides.

But, while natural gas will inevitably play a role as we make a transition to a clean energy future, it alone cannot deliver the reductions in global warming emissions that we need to avert the worst consequences of climate change. Natural gas also comes with other environmental and potential health risks and is subject to considerable price volatility. Because of these concerns, UCS emphasizes the value of diversifying our energy base to include more renewable sources of energy like wind and solar photovoltaics. Our research shows that the United .States. will be better off in the long run by backing these renewable sources rather than sinking too much into capital investments like pipelines or retrofits to support natural gas.

To understand this more fully, let’s look more closely at these choices.

First, of all, it is important to note that natural gas results in about 60 percent fewer carbon emissions at the smokestack than coal. That’s certainly an improvement, but it’s paltry compared with zero-carbon options like wind and solar which accounted for a full one-third of all new electric generating capacity in the United States last year. Plus, recent scientific research indicates that the life-cycle global warming emissions from natural gas use are considerably greater than what occurs when simply burning the natural gas to produce electricity. This is because the drilling and extraction of the natural gas from wells, and its transportation in pipelines, all result in the leakage of methane—a far more potent global warming gas than carbon dioxide.
 
By comparison, renewable sources like solar and wind are already viable zero-carbon options. Photovoltaic solar panel prices have fallen by 50 percent over the past several years. And, according to the latest figures, wind power now accounts for more than 10 percent of all electricity generated in a number of U.S. states, including South Dakota, Minnesota, and Iowa. UCS strongly favors the modernization of our electric grid to allow for as much as 80 percent of our electricity to be generated by such renewable sources by 2050. That strategy will do the most to benefit our environment and combat climate change.

Another major variable in the equation are concerns about the environmental and health impacts of hydraulic fracturing or “fracking”.  Fracking has been  a key driver for significantly increased natural gas supplies from shale and other natural gas deposits and record low natural gas prices. Fracking involves drilling a well into shale formations deep underground and injecting millions of gallons of water, chemicals, and sand under high pressure to break open fissures in the rocks and release the natural gas. In addition to using millions of gallons of water for each well, this process can have adverse impacts on water quality, the environment, and public health. For example, a 2011 National Academy of Sciences study found the first systematic evidence of methane contamination of private drinking water at sites above the Marcellus and Utica formations in Pennsylvania and New York where shale gas was being extracted. Based on analyses of 60 private wells in the region, methane concentrations in the groundwater were found to be 17 times higher on average in areas with active drilling and extraction than in non-active areas. The process of fracking also uses hundreds of potentially hazardous chemicals throughout the shale gas extraction process, including some that are known to cause cancer or otherwise threaten human health.

There is no question that natural gas has an important interim role to play in enabling our transition to a clean energy future. Among their many benefits, natural gas power plants can be quickly ramped up or down as needed to generate electricity and are therefore a good complement to variable resources like wind power. Right now, however, with such low natural gas prices and no long-term national policy support for renewable energy, there is a real danger that natural gas could instead crowd renewable energy out of the market. We at UCS believe scaling up renewable energy sources now is critical to further reducing their costs, encouraging innovation, and building the low-carbon energy system we need in the future. From a climate perspective, the window for this transition is very small and it’s growing smaller every year we delay.

 

Dr. Rachel Cleetus is an economist with the UCS Climate and Energy program. She holds a Ph.D. and an M.A. in Economics from Duke University and a B.S. in Economics from West Virginia University. The focus of her work is designing and advocating for effective global warming policies at the federal, regional, state and international levels. These include policies that put a price on carbon, as well as sector-based approaches to promoting efficiency, renewable energy, and R&D in clean technology. She also analyzes the economic costs of inaction on climate change.

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