When Carnegie Mellon University (CMU) professors Costa Samaras and Ines Azevedo wanted to measure the amount of carbon dioxide (CO2) emitted by US electricity producers, they found themselves moving into unexplored territory.
“We were really surprised to see that no one had done this,” says Azevedo, an associate professor of engineering and public policy at CMU.
So they, along with a team of CMU students and faculty, created the Carnegie Mellon Power Sector Carbon Index. Sponsored by the Mitsubishi Hitachi Power Systems, the index compiles publicly available data from the Environmental Protection Agency and the Department of Energy to illustrate electricity-related CO2 emissions.
And it’s a good thing they did, as their findings, which were revealed recently during Carnegie Mellon Energy Week, showed that CO2 produced by the sector has dropped by 24 percent nationwide since 2005.
“We knew it had gone down, but that it’s gone down almost a quarter is a big deal,” said Samaras, an assistant professor of civil and environmental engineering at CMU.
They attribute the decrease to a number of factors, primarily the retirement of coal-fired power plants across the country as the market moves to natural gas. Western Pennsylvania has already seen the result of such a shift, as Consol vowed to spin out their remaining coal assets to focus solely on natural gas. Yesterday, another company, FirstEnergy Corp., announced plans to sell part of the shuttered Hatfield’s Ferry coal-fired power plant in Greene County to a New Jersey-based natural gas developer.
Their research also showed that, within the same time period, the total energy produced by renewable sources such as wind and solar shot up from nine to 15 percent.
Samaras and Azevedo will continue to use the index to track the nation’s electricity-sector emissions for the foreseeable future. It will also measure the environmental impact of the US power grid all the way back to 1990, as well as provide a summary of how much electricity generation comes from coal, natural gas, nuclear and renewables.
“We want to make sure we’re able to communicate to stakeholders and policy makers, as well as the public, how things are going carbon-wise,” says Samaras, adding that anyone can download or share the index for their own purposes.
Azevedo believes the study comes at a time when progress made by the industry is being threatened by federal policy. She points to executive orders signed by President Trump that relax environmental regulations for the coal industry.
The fluctuation of energy prices also determines whether coal becomes the preferred energy source over its biggest competitor, natural gas. As of last December, the index showed that emissions rose by one percent, an increase Samaras says is directly related to more coal being burned than natural gas.
“These are some things that we’re trying to keep an eye on,” he adds.
While the numbers show promise, Samaras and Azevedo say more must be done to reach the deep decarbonization—a term referring to an 80 percent or more reduction in CO2 emissions—necessary to tackle climate change. To achieve such a goal, Azevedo says the US must continue to decarbonize the power sector and invest in making buildings more energy efficient.
They also believe that Pennsylvania—a coal- and natural gas-producing state known for having some of the country’s unhealthiest air quality—is in a position to become a model of drastic CO2 reduction.
“The exciting thing about Pennsylvania is it’s a story of energy,” says Samaras, listing off several energy milestones in the region, including the first coal mine in Mt. Washington, the first gas well in Murrysville, and the first nuclear power plant in Shippensburg. “A lot of the technology that drove industry in the US was born here, and we think that the next energy revolution can be disseminated from here.”
