Biomass-fired steam-injected gas-turbine cogeneration for the cane sugar industry

Considerable amounts of power could be produced at cane-sugar factories for export to the utility grid (while meeting onsite energy needs) by adopting more energy-efficient cogeneration and sugar-processing technologies. With off-season operation of the power plant using an auxiliary fuel (e.g. stored cane tops and leaves), still larger quantities of electricity could be exported. Modern condensing-extraction steam turbines have been installed in several factories worldwide. By comparison to these, steam-injected gas turbines fired with gasified biomass, which could become commercially available within a few years, offer higher thermodynamic efficiencies, lower unit capital costs, and weaker scale economies. A case study based on the Jamaican Monymusk factory indicates attractive rates of return on gas turbine investments, compared to those for steam turbines. Gas turbines have the potential to provide some 1000 GWh per year of electricity using the presently produced cane residues in Jamaica. Globally, over 50,000 MW of gas turbine capacity could be supported with the 1985 level of cane-residue production. The costs of producing this electricity is estimated to be lower than the estimated costs for power from most central station alternatives, including hydro.