Using natural gas as an environmentally sustainable power source with solid oxide fuel cells

Policies, research and pilot projects to commercialize carbon capture in the power sector have focused on coal plants. However, the expected world-wide consumption of natural gas in the power sector is not consistent with a sustainable environmental future without also employing carbon capture technologies to natural gas plants. One reason carbon capture from natural gas has not received much attention is, as will be discussed below, the very high cost of carbon capture from natural gas plants compared to the already considerable cost of carbon capture from coal plants. Capture of carbon with conventional natural gas turbines is not economically practical. Consequently, a different technology is needed to generate electricity from natural gas in the power sector. This technology should be competitive with natural gas turbines (disregarding its ability to employ carbon capture). This technology should permit the capture of carbon at low cost. Ideally, the cost should be significantly lower than the cost of carbon capture from coal plants (as measured by the cost per ton of captured CO2). Solid oxide fuel cells (SOFCs) are the leading technology to meet these requirements. Their emissions of CO2 without carbon capture are relatively low due to their high efficiency. Significantly, in the SOFC exhaust, CO2 is only comingled with water and unreacted CH4. This enables low-cost separation of CO2. In addition, the efficiency losses from the application of carbon capture are minimal compared to the significant efficiency losses when carbon capture is applied to coal power plants or natural gas turbines. The primary barrier to the uptake of SOFCs is the development of a grid-scale SOFC with a comparable cost and reliability compared to the natural gas turbine. With a cost-competitive grid scale SOFC technology, the additional cost of carbon capture would be minimal compared to the cost-prohibitive carbon capture technologies that are available for coal power plants and natural gas turbines. Consequently, commercialization of carbon capture in the power sector could be achieved with policies that impose a much lower burden on the economy and a much lower increase of the cost of electricity than is now the case. While the current research to achieve cost-competitive and reliable SOFCs for grid-scale application is encouraging, these efforts should be significantly increased in order to achieve more rapid technology development and the opportunity to achieve grid-scale commercial application, a necessary step that enables further cost reduction (technology learning, or, learning by doing).