Integrated Micro-Turbine and Rotary-Kiln Pyrolysis System as a Waste to Energy Solution for a Small Town in Central Italy: Cost Positioning and Global Warming Assessment

Solid waste, and bio-residuals in general, are usually disposed of or alternatively converted into energy by means of medium to big scale power plants. For isolated communities, usually in protected natural areas, this turns into high energy and waste management costs because of their intrinsic distance from landfills and power plants. Considering also the electric dependency from the grid, small towns are commonly showing low sustainability. This paper focuses on both problems by evaluating the economic feasibility and the global warming contribution of an innovative micro scale waste to energy system based on a microturbine fuelled by waste pyrolysis gas. The plant reaches high efficiency, considering the scale, because of its high regenerative rate and is tailored to the waste disposal needs of Giano Dell'Umbria a small town in central Italy. The economic analysis was carried out, with the Net Present Value method, to determine the expected capital cost of the plant considering that the innovative technology utilized does not allow a reliable cost evaluation. The global warming contribution was calculated considering CO2 and CH4 avoided emission from landfilling and the better CO2 emission rate of such a technology with respect to the status quo. Results obtained show an acceptable cost positioning for the plant that makes it an interesting solution for distributed waste to energy systems. Executive projecting and construction of the proposed technology was funded and a pilot plant will be built and tested in 2002, in a laboratory facility of the University of Perugia