STUDY: TOTAL EMISSIONS REDUCTIONS FROM CCS LIKELY 70%, NOT 90%

Tamar Hallerman
GHG Monitor
2/1/13

A new study says the emissions reductions achieved from power plants outfitted with carbon capture and storage technology may not be as high as many figures suggest. A University of Bath report, published in the current issue of the journal Energy Policy, argues that while units with CCS could deliver a 90 percent reduction of CO2 emissions from a power station’s operational phase, when the full upstream emissions from a fuel stock’s production are incorporated, the technology only captures about 70 percent of total emissions. In an interview this week, co-author Geoffrey Hammond, founder director of the university’s Institute for Sustainable Energy and the Environment, said that ignoring upstream processes, as most figures do, provides an inaccurate picture of a technology’s potential. “You need to look at all of the lifecycle emissions, including from upstream processes. If you ignore them and just look at operational, or stack, emissions you’re going to be misled in your findings,” he said. “There’s no doubt that having a CCS plant is better than having one without CCS, but in order to get realistic estimates of how good it’s going to be to you, you’ve got to take into account upstream emissions.”

Hammond and co-authors Hayley Howard and Craig Jones added coal’s full lifecycle emissions when determining the reductions achieved using CCS technology on a coal unit. After the team incorporated emissions from mining—and the fugitive methane emissions that escape as a result—as well as the average penalties for processing, transportation and facility construction, combined with the emissions once the feedstock is combusted, it found that total emissions reductions are far lower than advertised on average. “The present study has indicated that that coal CCS is about two-thirds lower in terms of greenhouse gas emissions in comparison with conventional coal-fired plant (without CCS), a fall from 1.09 to 0.31 kg CO2e per kWh,” the study says. “Thus, CCS is CCS is likely to deliver only a 70 percent reduction in carbon emissions on a whole system basis (including both upstream and operational emissions), in contrast to the normal presumption of a 90 percent reduction.”

The study also argues that when taking into account the full-cycle emissions from coal units with CCS, the technology may not be all that much more attractive than unabated natural gas, especially when one takes into account the health and environmental impacts of coal-linked pollution like particulate matter and mercury.

Hammond: Governments Should Change Calculations

The report highlights the disconnect between a technology’s lifecycle emissions levels and the stack emissions figures that many governments use in their official accounting methods. Hammond noted how the U.K.’s Department of Energy and Climate Change does not account for upstream greenhouse gas emissions in its current calculations. He said that if governments are serious about meeting stringent emissions reduction goals—the U.K. currently has a goal of cutting emissions 80 percent below 1990 levels by mid-century—they should take into account the fact that emissions reductions stemming from particular technologies may not be as high as many predict. “The challenge is much more stringent than they think it is, because they’re assuming they can build CCS power plants that will capture 90 percent of carbon emissions, when actually they’ll only be capturing closer to 70 percent,” he said. “They need to take into account these upstream emissions.”

Hammond said that his group’s study has gotten some to start examining the lifecycle emissions of energy technologies like CCS. “It’s not really been on the agenda of the community. It’s only been in the last few years that people have started to examine issues of this type, but people are starting to get the idea now,” he said.