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IEEFA op-ed: Reality of carbon capture not even close to proponents’ wishful thinking

August 08, 2019
David Schlissel

August 4, 2019 (Denver Post) — Jon Caldara’s op-ed on Xcel’s Colorado Energy Plan attacks the utility company and the broader environmental community, saying that the latter is motivated primarily by feelings of virtue rather than cold hard facts. Guess what? The facts are not in Caldara’s favor.

The only evidence Caldara presents for his opposition to the planned closure of two of the Comanche coal-fired plants is a study done for the U.S. Department of Energy by a former DOE employee.

Worse, a detailed review of the study shows that it is fatally flawed, based on overly optimistic and unsupported assumptions about the construction costs of carbon capture equipment as well as the effectiveness of such technology.

Further, the DOE-commissioned study completely ignores the fact that the financial viability of the entire project depends on being able to sell the captured carbon dioxide (CO2) for use in enhanced oil recovery activities. When the additional oil produced through this oil recovery is burned or used as a chemical feedstock, it, in turn, would emit substantial amounts of CO2, thereby offsetting reductions in emissions at the plant.

On the cost question, the DOE-commissioned report rests on the assumption that the carbon capture equipment could be built for 45 percent less than the only comparable unit currently operational in the U.S., a much smaller facility in Texas called Petra Nova that was launched late in 2016. The Petra Nova facility cost $1 billion (or roughly $4,400 per installed kilowatt). The DOE study asserts that the Comanche project could be built for just $2,450 per kw — but offers no evidence to support such a drastic reduction in cost.

The study also asserts that, on average, the Comanche plant would operate with a 75 percent capacity factor (that is, it would produce 75 percent of the electricity it is theoretically capable of producing during a given year) after the carbon capture retrofits are completed. A check of actual plant operating data conducted by the Institute for Energy Economics and Financial Analysis shows that since 2010 it has only achieved a 75% capacity factor in a single year — to assume that Comanche would perform this well on a consistent basis after all the new CO2 capture equipment is installed is highly unrealistic.

Similarly, officials from the DOE have reported that the average cost of capturing CO2 at Petra Nova is about $60 per ton. However, again with no actual experience on which to base its analysis, the study assumes that the cost of capturing CO2 at Comanche can be cut to between $36.42 and $39.70 per metric ton — a reduction of about 40% made, not by hands-on experience but by computer keystrokes.

Some of this assumed cost reduction can be traced to the study’s projection that the new Comanche CO2 capture equipment will operate at 90% effectiveness. When NRG built the Petra Nova plant it made similar projections.

However, results from the first two years of full operation show that the Texas facility captured between 65% and 70% of the CO2 at the plant, and that does not take into account the emissions from the natural gas turbine used to run the carbon capture equipment. Factoring those emissions into the equation lowers the effective capture rate to about 50%.

Performance at another plant, this one in Saskatchewan, Canada, has been similar. That plant, Boundary Dam Unit 3, was also built with the promise that it would capture 90% of the unit’s annual emissions, but overall, the plant has a capture rate of about 51%.

Here again, reality trumps Caldara’s wishful thinking. If Caldara is truly interested in cold hard facts, he would be better off doing a little more research.

*This article appeared in the Denver Post on August 4, 2019 under the headline: Reality of carbon capture not even close to proponents’ wishful thinking. David Schlissel was invited to submit a response to an editorial by Jon Caldera that argued against the closure of two coal-fired power plants and in favor of funding carbon capture storage to make the plants more economically viable. The original article was entitled: Xcel Energy should consider carbon capture to save the planet and our pocketbooks

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David Schlissel

David Schlissel is IEEFA’s Director of Resource Planning Analysis. His work focuses primarily on the technical and economic viability of resources being used or being proposed for use in the electric power sector.

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