Miscellaneous
Another approach that has received a lot of attention is the combination with fuel cells that can convert the chemical energy in pure hydrogen directly into electricity. The gas produced by gasification is especially suitable for this purpose, as the main additional treatment required is a CO shift that will convert all CO in the gas to additional hydrogen. Much development work has still to be done on fuel cells. Several types of fuel cell are being developed, including solid oxide, molten carbonate, phosphoric acid, and proton exchange membranes. At this stage of development it appears that the higher-temperature solid oxide and molten carbonate systems would best integrate with gasification-based systems for central station power production. The problem is that the gas for the fuel cells must be extremely pure. The target for natural gas is 70% efficiency, but our expectation is that at the time this can be realized the same efficiency can be reached with more advanced IGCC or similar cycles.