Coal remains the most abundant fossil fuel resource in the world, with the total recoverable reserves estimated in year 2008 to be 909 billion tons. The main approach to coal utilization is the direct combustion for electricity generation, which produces approximately 0.92 kg of CO2 per 1 kWhe of electricity generated. In spite of environmental concerns, coal is likely to remain one of the leading energy sources in future. Coal gasification technologies can substantially reduce greenhouse gas emissions through increased conversion efficiency. Further emission reductions are possible, if the process heat required to drive the gasification process is obtained from a CO2-free energy source such as concentrated solar energy, eliminating the need for combustion of a significant portion of the feedstock. In addition, elimination of internal combustion for supplying the process heat will mitigate contamination of the synthesis gas (syngas) with the combustion byproducts.
Steam and dry gasification processes involving H2O and CO2 as the gasifying agents, respectively, are considered. The studies are conducted for two possible scenarios: (1) electricity generation in a combined cycle power plant using the syngas produced by gasification, and (2) synthesis of gasoline from syngas.