Experimental–numerical analysis of a biomass fueled microgeneration power-plant based on microturbine

Thermal use of biomass may have a significant role in the scheme of distributed power generation from renewable sources as it is intrinsically programmable. Moreover, if the furnace is designed for flexible fueling (multifueling), this feature gives maximum flexibility also from the standpoint of fuel availability and storage over the year. To fully exploit the fuel potential, the optimal size for these systems is in the lower range end (100 kW) for reasons mainly related to the fuel logistic chain. A Combined Heat and Power (CHP) configuration is furthermore important to balance the relatively low electric efficiency (in the order of 15% and less). In this paper a technology based on an Externally Fired Gas Turbine (EFGT) fed by woody biomass is demonstrated in the range of 70 kW electric power output. A multifuel prototype power-plant realized at the University of Rome Tor Vergata is described, and experimental data in terms of power, efficiency and fuel consumption are presented. To better understand the impact of fuel properties on power-plant performance, a model has also been developed, by means of physical submodels describing each component of the power-plant (biomass furnace, heat exchangers, compressor and turbine). The use of simple economic and management models is also discussed to better assess the economic sustainability of the solution depending on the characteristics of the fuel (fuel-end), matched with the utilization pattern (user-end), with special regard to thermal energy value over the year.