A few weeks ago President Barack Obama announced plans to order the Environmental Protection Agency (EPA) to propose limits on carbon dioxide emissions from existing coal and gas-fired utilities by 2015. What wasn’t talked about as much is that, as important as it is for the future to reduce CO2 emissions, it’s equally vital that American finds a way to capture and store carbon dioxide as well.
The reality is that we’re never going to be able to fully reduce our carbon emissions unless we figure out a way to capture and store it for the future.
In case you’re unfamiliar with the process, carbon capture and sequestration (or storage) — known as CCS — is a physical process that involves capturing manmade carbon dioxide (CO2) at its source and storing it before its release to the atmosphere. CCS could reduce the amount of CO2 emitted to the atmosphere while allowing the continued use of fossil fuels at power plants and other large, industrial facilities.
An integrated CCS system would include three main steps:
- Capturing CO2 at its source and separating it from other gases.
- Purifying, compressing, and transporting the captured CO2 to the sequestration site.
- Injecting the CO2 into subsurface geological reservoirs.
Following its injection into a subsurface reservoir, the CO2 would need to be monitored for leakage and to verify that it remains in the target geological reservoir. Once injection operations cease, a responsible party would need to take title to the injected CO2 and ensure that it stays underground forever.
This issue has attracted two recent studies, each concerned with the potential for the U.S. carbon capture storage.
The first study was conducted by the U.S. Dept. of the Interior and the U.S. Geological Survey, and it was the first comprehensive national assessment of carbon dioxide storage potential. Researched for more than five years, the report shows that the U.S. has the potential to store a mean of 3,000 metric gigatons of carbon dioxide in geologic basins throughout the country.
That translates to about 500 years of storage capability.
I spoke to Peter Warwick, the USGS project chief for the study, and he said there were conditions on what basins could be assessed as viable, such as a required depth of 3,000 ft.
One problem that was underscored in the study is that the basins with the highest potential for carbon storage (the Western U.S. and the Gulf Coast) are located far away from the Southeast, Mid-Atlantic, and Ohio Valley regions, which happen to account for 65 percent of the U.S. current coal-fired capacity.
What that means is that a large number of new pipelines would be needed to be built to connect power plants and these storage basins, an infrastructure investment which would be quite costly.
“What was interesting was that the Gulf Coast had a very large storage potential; that’s because of the large area and also, it had a lot of regional seals, which would be needed to keep the carbon (that is captured) in,” said Warwick. “The EPA requires that any of the storage projects have to be in areas that have saline water, because groundwater that’s not protected is used as possible drinking water.”
Warwick added that the next study from the USGS on the issue will be to look at the economics of carbon capture, and how much it’s going to cost.
Those economics were covered in a second report released last month, this one by the U.S. Dept. of Energy. At the behest of Congress, Peter Folger, a specialist in energy and natural resources policy at the DoE, summarized the current research and development being undertaken thanks to the financing appropriated to CCS.
He notes that “to date, there are no commercial ventures in the United States that capture, transport, and inject industrial-scale quantities of CO2 solely for the purposes of carbon sequestration. However, CCS R&D has embarked on commercial-scale demonstration projects for CO2 capture, injection, and storage. The success of these projects will likely influence the future outlook for widespread deployment of CCS technologies as a strategy for preventing large quantities of CO2 from reaching the atmosphere while U.S. power plants continue to burn fossil fuels, mainly coal.”
Folger’s report goes on to say that outside factors like hydraulic fracturing would have a sizable effect on the U.S.’s CCS efforts, and that more Congressional funding and legislation are likely needed before any CCS programs can move forward.
Reports are one thing, but where do we actually stand when it comes to the technology of CCS being able to meet the demands? I spoke to Howard Herzog, who has been involved in carbon capture research for two decades, and for the past six years has run the Carbon Capture and Sequestration Database for the CCS Technologies Program at MIT.
The database tracks the progress of every carbon dioxide capture and storage project in the world, including power plant (projects over 60 MW) and non-power plant (projects between 1 and 50 MW) developments.
“We only rely on public sources for the database, and it used to be harder to track,” Herzog said. “But as the number of projects has dwindled, so it’s easier to keep track of.”
Currently there are only five U.S.-based power plant CCS projects either in the planning stages or under construction, and among those only the Kemper County, Miss. project is actually being built. On the non-power plant side, there are 10 projects either underway or in the planning stage.
To give you an example of how far away we really are from being fully capable and ready to do CCS on a large scale, Herzog cited ExxonMobil’s LeBarge plant in Wyoming, which has been operational since 2008.
The LeBarge project stores six million tons of CO2 per year, which is the equivalent of a 1,000 MW power plant. That storage would serve approximately one million households, Herzog said, but the entire U.S. would need a billion tons per year to operate on CO2 storage.
“LeBarge is a large project, but you would need about 170 LeBarge’s to really commit and be comfortable using this for the whole country,” Herzog said. “A couple hundred large-scale projects would make a big dent, but we only have a handful right now.”
Herzog said that “five years ago there was a feeling among people in the industry that we will need low-carbon technology soon because there will be [government] policies requiring it. But that has fallen apart both nationally and internationally, as the political will hasn’t been there, and then you throw in the world financial crisis over the past five years.”
Technology-wise, experts I spoke with agree that if money and legislation wasn’t an impediment, large-scale CCS “is ready to go,” Herzog said.
But the lack of any coherent policy initiative and consensus, combined with the exorbitant cost of building large-scale plants, have people like Herzog pessimistic.
“I think we’re at least 20 years away on the legislative side from having any kind of will and support (for CCS),” Herzog said. “Over the last 15 to 20 years, we’ve gained a lot of knowledge, and everything seems to be going in the positive direction. But the biggest problem with the capture side is the cost; it’s always going to be cheaper to put it in the atmosphere than to catch it and store it.”
“I think we’re at least 20 years away on the legislative side from having any kind of will and support (for CCS),” Herzog said. “Over the last 15-20 years, we’ve gained a lot of knowledge, and everything seems to be going in the positive direction. But the biggest problem with the capture side is the cost; it’s always going to be cheaper to put it in the atmosphere than to catch it and store it.”