The Outlook for Power Plant CO2 Capture

There is growing international interest in carbon capture and sequestration (CCS) technology to reduce carbon dioxide emissions linked to global climate change. CCS is especially attractive for electric power plants burning coal and other fossil fuels, which are a major source of global CO2 emissions. This paper describes the performance and cost of CO2 capture technologies for large-scale electric power plants including pulverized coal (PC), natural gas combined cycle (NGCC), and integrated gasification combined cycle (IGCC) plants. Different types of capture technologies, including pre-combustion, post-combustion, and oxyfuel combustion capture systems are discussed, along with the outlook for new or improved technology. Future cost for power plants with CO2 capture are estimated using both a “bottom-up” approach based on engineering analysis and a “top-down” approach based on historical experience curves. The limitations of such projections are discussed along with needs for future research, development and demonstration of CCS technology. The most urgent need at this time is financing for several full-scale demonstrations of CCS at coal-based power plants. INTRODUCTION On first hearing, the idea may sound a bit far-fetched. To avoid emitting billions of tons of carbon dioxide (CO2) to the atmosphere—the major greenhouse gas associated with global warming—engineers propose to equip coal-burning power stations with chemical plants that strip CO2 from the flue gases before they go up the chimney. The concentrated CO2 would then be compressed to a liquid and piped to a storage site where it would be injected deep underground. There it would be trapped by impermeable layers of rock and very slowly, over centuries, transform into solid carbonate minerals. This method of sequestering CO2 would not come cheap—if applied to an existing power plant today, the cost of generating electricity would nearly double. Surely, one would think, there must be an easier way to reduce power plant CO2 emissions. Such was the general view when the idea of carbon capture and sequestration (CCS) was first proposed as a greenhouse gas mitigation strategy three decades ago (Marchetti 1977). But over the past decade things have changed. Scientists, engineers and policy analysts have been taking a closer look at CCS and finding that it could indeed make sense both technically and economically—making it a potentially important player in mitigating global climate change. Why the interest in CCS? Current worldwide interest in CO2 capture and sequestration (or storage) stems principally from three factors. First is the growing evidence that large reductions in