The U.S. Environmental Protection Agency (EPA) issued class VI permits to Indiana’s Wabash Carbon Services on Jan. 24 for the state's first two wells that will store carbon dioxide underground. The technology is part of the capture and sequestration program that proposes to reduce the effects of greenhouse gas emissions and slow the effects of climate change.
Mark McCready, a professor of engineering and senior associate dean for research and faculty affairs, explained how current industrial processes, many of which include burning fossil fuels, result in carbon dioxide being released into the atmosphere.
“There are many processes that at the end of the day [produce] carbon dioxide,” McCready said. “Whether it's combustion processes or various chemical processes, you end up with carbon dioxide. And so nowadays, mostly we just send that to the air.”
McCready also pointed out significant contributors to carbon dioxide emissions aside from transportation.
“Besides emissions from trucks, cars and other kinds of transportation vehicles, heavy industry produces lots of carbon dioxide,“ McCready said. "And really big ones, of course, are power plants, where you burn coal or natural gas or produce very large quantities of carbon dioxide.”
Emily Grubert, an associate professor of sustainable energy policy in the Keough School of Global Affairs, said she briefly took on a role at the Department of Energy as an academic. In that role, she became involved with the conversation surrounding carbon sequestration and the 45Q tax credit. The 45Q tax credit was first introduced in 2008 by the Internal Revenue Service to incentivize companies to geologically store carbon dioxide, rather than release it into the atmosphere.
“I was pretty involved in a lot of the carbon sequestration conversation in that role,” Grubert said. “And since I've left things like the 45Q tax credit in particular have started to become a lot more obviously relevant. In Indiana the EPA approved a class six carbon sequestration ... and there's a whole bunch of projects that are potentially going forward.”
Grubert said many conversations regarding carbon sequestration revolve around where the carbon dioxide is being sourced from, and that in most cases carbon dioxide from different sources is stored in similar ways.
“I think one of the things that often gets confused in a lot of these conversations is what carbon you're actually talking about because it looks pretty similar across a bunch of different sources,” Grubert said. “So the way that you would sequester carbon dioxide that you're taking directly out of the atmosphere, which you could theoretically think about as negative emissions under certain circumstances, that infrastructure that you're using to store it is the same as if you're taking carbon dioxide off of a coal plant that you might have shut down otherwise.”
Effectiveness of the capture and sequestration technology
Emissions from industry processes make up about 30 percent of total greenhouse gas emissions, according to the EPA.
Grubert said the current system of tax credits makes her nervous because if a large percent of emissions come from these large industry complexes, it could incentivize plants that otherwise would have shut down to stay open.
“I think one of the ones that I get really kind of nervous about given the way that the tax credits are set up is if you basically have a coal plant that would otherwise have shut down and been replaced with something cleaner,” Grubert said. “But now you're incentivizing it to store carbon dioxide underground, it's going to run much longer. Which means it's going to be [producing] carbon dioxide that wouldn't have existed otherwise.”
“If you didn't have this incentive to put the carbon dioxide underground, you wouldn't have made the carbon dioxide in the first place,” Grubert continued.
Grubert explained that the capture and sequestration method is a mitigation strategy. By taking carbon dioxide off of an industrial process or power plant, capturing that carbon dioxide and putting it underground, “it's basically preventing new emissions from going into the atmosphere.”
McCready explained that the carbon sequestration program aims to inject up to 1.67 million tons of carbon dioxide into the wells per year, which would offset the emissions of about 400,000 cars.
“It's like taking 400,00 cars off the road,” he said. “Indiana has 2.5 million cars. So it would be a substantial reduction relative to the emissions of Indiana motor vehicles.”
However, McCready said the reduction of emissions analysis is missing the consideration of how much front energy is being used to sequester the carbon dioxide and store it in the underground wells.
“The thing that's missing in that analysis is it took them more energy to do this,” McCready said. “We always seem to come out at about 30 percent more energy. So if you didn't sequester the carbon dioxide at all, you would have saved 30 percent of that front-end energy.”
Criticisms of carbon sequestration
Critics of the carbon sequestration project claim that the process has not been tested enough.
Yamil Colón, an assistant professor of engineering, addressed the criticism that the technology has not gone through enough testing to prove that it is a viable solution for carbon dioxide emissions.
“I think that the criticism is valid, but I also don't necessarily know how to get around it ... only time will tell whether or not some of the concerns that they have will come to pass or not.”
Another criticism of the carbon sequestration program is that it promotes a continued reliance on fossil fuels. McCready addressed this and said that the criticism doesn't consider how we continue to require nuclear energy and fossil fuels, and that alternative, renewable forms of energy, like wind and solar, can only go so far.
McCready used National Grid, a network that tracks the electric power transmission in Great Britain, to research the main sources of energy used. He explained how there were days when 40% of the energy came from wind and solar.
He also said that most power continues to come from fossil fuels and other sources, like nuclear power. Wind and solar power are good in theory because they are renewable, but until there is a way to store this power and make it more accessible, its usage is limited.
“We need nuclear, we need fossil fuels,” McCready said. He believes that if people want to make the transition from fossil fuels to “green” sources that don't produce carbon emissions go faster, the only way is to build nuclear power plants.
Grubert proposed another solution to transitioning away from fossil fuels. She explained how switching to wind and solar power is an important method for decarbonization.
Grubert added that another important method to reduce carbon dioxide emissions is using less energy to achieve the same service or outcome. She said that there are many different routes to achieve this, but that “carbon capture and sequestration is probably a pretty minor one.”