Abby L. Harvey
GHG Monitor
5/9/2014
The National Climate Assessment released by the Obama Administration this week emphasizes the uncertainty of carbon capture and storage technology as a means to combat climate change, seemingly standing in contrast to the declarations from the Environmental Protection Agency in relation to regulations for new power plants that CCS has been “adequately demonstrated.” The current readiness of CCS technology has been a key issue in recent months as the EPA’s New Source Performance Standards effectively require CCS for any new coal plant to be built, but the National Climate Assessment’s conclusions on CCS appear to conflict with EPA’s.
While CCS is noted as a valuable tool in reducing emissions, the assessment states that “the costs and effectiveness of many of these technologies remain uncertain: continuing study of their performance is important to understanding their role in future mitigation decisions.” The report also calls into question the feasibility of the technology, particularly in a future where water scarcity may be wide-spread. “Substantial amounts of water are used to separate CO2 from emissions and to generate the required parasitic energy. With current technologies, CCS can increase water consumption 30% to 100%. Gasification technologies, where coal or biomass are converted to gases and CO2 is separated before combustion, reduce the energy penalty and water requirements, but currently at higher capital costs,” the assessment says, adding, “As with other technologies, technology and design choices for CCS need to be balanced with water requirements and water availability. Climate change will influence the former via effects on energy demand and the latter via precipitation changes.”
The assessment includes two scenarios—one that projects the impacts if emissions continue to increase and one “low-carbon” scenario. According to the assessment,, even in a low-carbon future, a 3-5 degree rise in temperature is projected, as opposed to the 5-10 degree increase in the higher emissions scenario. To achieve the “low carbon” scenario, the assessment states, “Early and large reductions in global emissions would be necessary to achieve the lower emissions scenarios … including reduction of CO2 emissions from energy supply through the promotion of renewables (such as wind, solar, and bioenergy), nuclear energy, and coal and natural gas electric generation with carbon capture and storage.” However, the assessment later states, “Although the potential opportunities are large, many uncertainties remain, including cost, demonstration at scale, environmental impacts, and what constitutes a safe, long-term geologic repository for sequestering carbon dioxide.”
