The invention relates to direct conversion of coal into electricity in a high temperature electrochemical generator in a single step process. This novel concept promises nearly doubling the conversion efficiency of conventional coal-fired processes and offering near-zero emissions. The improved efficiency would mean that nearly half as much coal is mined and transported to the power plant, and half the greenhouse gases and other pollutants such as sulfur, mercury and dioxins are produced. It also offers several crucial distinctions from conventional coal-burning processes. Since the process does not involve the combustion of coal in air, it does not involve nitrogen and hence generates practically no NOx. Accordingly, there is also no latent heat lost to nitrogen. In this process, the oxygen necessary to oxidize coal is supplied through an ion selective ceramic membrane electrolyte. The resultant product stream primarily consists of CO2 and, hence, it is easier and cheaper to capture and sequester, compared to waste streams from conventional combustion processes where CO2 ordinarily constitutes about 15-20% of the flue stream, in which case it may first be separated from other constituents before sequestration.