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Environment

Colorado could stuff its CO2 deep in the ground to slow climate change

Carbon sequestration may be a small piece of the greenhouse puzzle now, but underground sites show promise for cooling the planet’s future.

carbon sequestration carbon dioxide greenhouse gases Colorado task force
A press conference about CO2 sequestration at the Boise Inc. property in Walulla, Wash., Friday, July 26, 2013. Researchers based at the Pacific Northwest National Laboratory in Richland are injecting carbon dioxide 2,700 below the surface in a test well on the Boise Inc. paper mill property on the Columbia River. (AP Photo/Walla Walla Union-Bulletin, Greg Lehman)
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Colorado has snuffed the carbon-spewing smokestacks of some of its most noxious coal-fired plants.

It’s tasked the oil and gas companies with plugging methane leaks in pipelines and capping carbon-weeping abandoned wells.

And the state wants belching, gas-fueled V8s to turn themselves in for EVs with no tailpipe.

Now, in another potentially crucial push to quarantine CO2 and combat greenhouse gas emissions, state leaders want a system to cram some of the remaining torrents of carbon emissions underground and lock them up in salt formations at least 3,000 feet deep. 

A task force on Colorado’s potential for carbon sequestration, convened by the Colorado School of Mines and the Colorado Energy Office, is finishing up a report calling on the legislature and regulators to boost the idea. They want funding of carbon-capture research, for example, and state agencies to smooth the way for CO2 pipelines. 

TODAY’S UNDERWRITER

Carbon sequestration could prove big in the climate change battle on two fronts. First, efforts to slash Colorado carbon emissions by 50% by 2030 could fall short if EVs do not replace gas engines fast enough, or if cleanly electrifying building and home systems goes slower than hoped. Some industries’ use of fossil fuels will prove stubborn, such as regional cement kilns requiring extremely high heat. Perfecting and deploying carbon capture technology could get Colorado to its emissions goals as fossil fuel use winds down.

Second, with the world apparently skidding past the 1.5-degree Celsius warming cap global scientists have targeted as the upper limit for humans readily adapting to climate change, carbon capture could in theory pull past carbon emissions out of the atmosphere and try to reverse the temperature climb. Experiments to do just that are underway in Iceland and other locations. Colorado’s geology, in both the northeastern oil fields and southwestern salt formations, could be one of the places used to pull the Earth back from the temperature brink through sequestration. 

carbon capture and sequestration U.S. Geological Survey
Details of a map from U.S Geological Survey studies of potential underground basins for carbon capture in the southwest region. (U.S. Geological Survey)

“How are we going to get to zero carbon emissions and recognize the fact that as a society, we’re still going to need things like cement and concrete, and some of these things are hard to decarbonize?” said Pat O’Connell, an advisor to the Colorado task force and a New Mexico engineer and energy analyst with Western Resource Advocates. 

“We’re going to need technologies like carbon capture, storage and use to get there,” O’Connell said. 

Colorado’s 2005 benchmark for CO2 emissions was about 140 million tons a year. From there, state law demands the total to be cut by 26% in 2025, and 50% in 2030.

To give an idea of the scale of the largest emitters, the Rio Grande cement plant in Pueblo emitted 802,000 tons in 2020, according to the EPA. Many gas- and coal-fired power plants were over 1 million tons each, and the emissions champ was Xcel’s Comanche complex in Pueblo, at 4.5 million tons. 

Task force members also want to ensure that possible future pipelines, drilling and underground salt dome storage for carbon meet the environmental justice provisions codified in successive rounds of greenhouse gas laws. In other words, don’t exacerbate past pollution injustice against low-income and minority communities by desecrating tribal lands with pipelines, or damaging the drinking water of rural neighborhoods. 

“When we proceed, we need to make sure we do a better job locating and operating the new stuff, so that we don’t perpetuate the environmental justice problems that we’ve created,” O’Connell said. 

carbon capture and sequestration Lafarge Holcim Florence, Colorado
Large cement factories are good candidates for carbon sequestration, as they require intense heat that is most easily generated by carbon-producing fossil fuels. Lafarge Holcim in Florence is one plant studying demonstration projects for CO2 capture. (Lafarge Holcim handout)

The Carbon Capture, Utilization and Sequestration task force is not recommending specific projects for Colorado, but members have discussed where the state offers potential: 

  • Hard-to-decarbonize industries: While electric utilities are changing over to cleaner fuels relatively quickly, some of Colorado’s biggest greenhouse gas polluters have no easy switch to make. The state’s three major cement-baking kilns are prime targets for future carbon capture. Firing lime and other materials to make “clinker” for cement requires huge amounts of fossil fuel burning. Lafarge Holcim’s plant in Florence has been studying underground storage possibilities, though details haven’t emerged. 
  • Alternative uses of carbon: Oil and gas producers have injected CO2 underground to revive production in depleting fields, though some researchers are leery of using captured CO2 in an industry responsible for creating a large portion of greenhouse gases to date. Concrete producers are studying whether carbon produced in the cement portion of the material could be recaptured in the concrete itself, locking it up for decades if not centuries. 
  • Pipelines to salt deposit injection sites: Salt domes built up when Colorado and other Western states were under ancient oceans create impermeable vaults for carbon. But you have to get the gas from the cement plants or other emitters to distant injection fields. Legislation could hand permitting and eminent domain rights to the Public Utilities Commission or another agency, but task force members do not fully agree on how much power to suggest be written into law. 

After meeting for months, task force members are optimistic Colorado is ready to fund research and demonstration projects and move forward on enabling rules, said Laura Singer, carbon capture program manager for the Colorado School of Mines. 

“It just needs a little more time to kind of develop to the scale,” Singer said. “And actually, the only way that kind of development is going to happen is just by starting to build projects and learning by doing.” 

Scaling up projects will also require educating the public, Singer said. People will wonder about injecting carbon into saline formations that include some water, but they need to know the Colorado salt formations are much deeper than drinking water sources. The saline aquifers are “brackish, non-potable water,” she said. Naturally occurring carbon dioxide formations are already underground in many locations.

U.S. Geological Survey studies show federal researchers have looked at potential storage qualities at basins in the far southwest and northwestern corners of Colorado, and in the northeast Denver Basin in many of the same areas as oil and gas exploration. 

States pursuing carbon capture now have significant federal money to help, Singer and O’Connell noted. The federal infrastructure stimulus package just signed by President Biden includes $12 billion to distribute to states for carbon capture, pipeline development, technology competitions and storage projects 

State officials, academic researchers and private industry need to position themselves to jump on those opportunities, Singer said. “There are big federal expenditures coming down the pike in this area for research and demonstration.” 


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