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Could Carbon Capture Keep the Lights on in a Carbon-constrained World?

By -- April 2, 2009

A few weeks ago, the Congressional Research Service (CRS) published a report on carbon capture and storage (CCS) technologies for coal-fired power plants.According to CRS, commercialization and widespread deployment of CCS will require “demand pull” regulation, such as Clean Air Act New Source Performance Standards, combined with cap-and-trade or carbon taxes; and it will require support for “technology push” RD&D (research, development, and demonstration) via government grants, tax preferences, and loan guarantees.

CCS will not be deployed on an industrial scale without “demand pull” regulation, because burning coal with CCS will always be more expensive than burning coal without it. Yet “technology push” RD&D to reduce CCS-related cost penalties is also critical. Although CRS does not explicitly say so, it implies that if CCS costs do not decline dramatically, carbon caps or taxes would make coal generation uneconomic. Absent relatively inexpensive CCS, carbon penalties could easily decimate the single largest source of electric power in the United States and, indeed, the world. CRS cites MIT’s estimates of the increase in electric generating costs (on a levelized basis) due to CO2 capture at the post-combustion, pre-combustion, and combustion phases of a plant’s operation:

  • Post-combustion capture using monoethanolamine (MEA) as a CO2 absorber increases generation costs 60%-70% for new construction and 220%–250% for retrofitted existing plants.
  • Pre-combustion capture using integrated gasification combined cycle (IGCC) increases generation costs 22%–25% for new construction.
  • Combustion capture in oxygen-fueled boilers increases generation costs 46% for new construction and 170%–206% for retrofitted existing plants.

CCS increases generating costs not only because the technology is advanced, but also because CCS plants divert a portion of the thermal energy that would otherwise produce electricity into capturing CO2 and compressing it into a liquid suitable for transport and storage.  MIT estimates, for example, that post-combustion capture with MEA reduces generation efficiency by 25%–28% for new construction and 36%–42% for retrofitted existing plants.What boggles the mind is the scale on which CCS would have to be deployed to preserve coal-generation in a carbon-constrained world.According to CRS, the world meets 25% of its primary energy demand with coal, a number projected to increase steadily over the next 25 years. In 2005, coal was responsible for about 46% of the world’s electric power generation, including 50% of the electricity generated in the United States, 81% of the electricity generated in India, and 89% of the electricity generated in China.The United States has more than 300 GW of coal-fired capacity; China has about 600 GW—and China added 90 GW in 2006 alone!Coal-fired generation is expected to increase 2.3% annually through 2030, with resulting CO2 emissions estimated to increase from 7.9 billion metric tons per year to 13.9 billion metric tons per year.CRS comments: “Developing a means to control coal-derived greenhouse gas emissions is imperative if serious reductions in worldwide emissions are to occur in the foreseeable future.” Yup, there’s no way to reduce worldwide emissions without controlling coal-derived emissions. In addition, and more importantly, if CCS costs do not drop sharply, pricing carbon could simply kill coal, condemning millions to freeze in the dark—a politically unsustainable outcome.Is affordable, industrial-scale CCS just around the corner? Apparently not. “Developing technology to accomplish this task in an environmentally, economically, and operationally acceptable manner has been an ongoing interest of the federal government and energy companies for a decade,” says CRS. ”But,” CRS continues, “no commercial device to capture and store these emissions is currently available for large-scale coal-fired power plants.”

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