SciTech

Researchers study life-cycle fuel emissions

In a recently published paper called “Comparative Life-Cycle Air Emissions of Coal, Domestic Natural Gas, LNG, and SNG for Electricity Generation,” Carnegie Mellon researchers reported that natural gas may not be the most viable energy resource for future production of electricity.

Appearing in the Journal of Environmental Science and Technology, this paper is the result of a study carried out by civil and environmental engineering graduate student Paulina Jaramillo, Tepper School of Business professor W. Michael Griffin, and engineering and public policy professor H. Scott Matthews.

The purpose of this study was to analyze the life-cycle greenhouse gas emissions of different fuels. That is, researchers analyzed the environmental impact of burning, mining, processing, transporting, and combusting various fuels.

Griffin, who is joint researcher and executive director of the Green Design Institute, said that his efforts were a way “to understand the environmental impact” of a fuel “through its complete life-cycle.”

From a purely chemical standpoint, natural gas is less of a pollutant than coal because it burns cleaner.

The life-cycle approach taken by researchers in this study, however, offers a more accurate representation of the ecological consequences of fuel use.

In particular, liquefied natural gas (LNG) is imported from other countries, and so there are other factors that come in to play than simply burning the fuel.

One such factor is the loss of fuel during transportation. Griffin said that this loss is “both an economic and environmental loss.”

The paper also describes the economic history of natural gas. According to this paper, consumption of natural gas spiked in the late 1990s due to its cheaper cost and environmentally friendly combustions.

As a result, the government invested heavily in natural gas power plants, hoping that these plants would help fulfill the increased demand for energy in the United States during that time.

High demand for natural gas first led to rising prices; in the early 2000s, it resulted in a lack of adequate supply for these power plants.

Currently, many of these plants are running empty and represent a loss of public money.

In response, Griffin said, “We must be more cautious when making decisions that have a significant effect on the future.”

The study argues that investment in any kind of energy facility must only be considered after all of the facts about the different fuels are known and implications of using coal or LNG are understood.

In a recent Carnegie Mellon press release, Matthews stated, “Making this investment ultimately locks us into certain technologies that make it harder for us to change paths in an increasingly carbon-constrained world.”

Griffin said, “The future is an ever-evolving concept. Advancement of technologies may bring about changes that may be almost impossible to predict.”

According to Griffin, one technological possibility is the use of carbon capture and sequestration (CCS).

CCS involves the storage of CO2 underground, thus reducing carbon emissions and curbing environmental damage.
Griffin said that this technology is “a definite, viable option” for the future.

The paper also suggests that,“advanced technologies are important and should be taken into account when examining the possibility of doing major investments in liquefied natural gas (LNG) infrastructure.”

If CCS were to be implemented, for instance, the use of coal as a fuel may actually be less detrimental than natural gas.

According to Griffin, a large-scale outlay on power plants, based on generation of electricity from natural gas, would be a rash decision.
Griffin said “I would request people to slow down and get their breath” before reaching any conclusions.