The United States produces more than 70% of its electricity from fossil fuels and nearly 50% from coal alone [U.S. Energy Information Administration, 2009]. Worldwide, the percentages are similar, making coal the single largest fuel source (42%) for electricity generation, followed by natural gas (21%) [International Energy Agency, 2009]. Dramatic improvements in the efficiency of electricity use and expanded use of renewable and nuclear energy can make important contributions to reducing carbon dioxide (CO2) emissions from electricity generation. However, we see no way to achieve an order of magnitude reduction in those emissions by the latter part of this century without some continued use of fossil fuels [Morgan et al., 2005]. This means that an essential part of any portfolio for emissions reduction will be technology to capture CO2 and permanently sequester it in suitable geologic formations.