An innovative 10 kW microcogenerator suitable for off grid application and fed with syngas or biogas

The paper deals with a microcogenerator prototype of 10 kW of electric power and about 20 kW of thermal power, suitable for indipendent local grids (such as small farms or small residential sites) fuelled by gas produced from biomass (both gasifiers or biogas plants). Small power systems (i.e. about 10 kW of electric power) are not optimized to be fed by low heat value gaseous fuels produced by gasifier or biomass plants or blends of them. Most of them have been provided with induction generators and conceived to be grid connected, while in most cases these plants must represent a form of indipendent energy production system, so not making easily possible their running in remote locations. The protoype presented in the paper was conceived since the beginning in the simplest way: the internal combustion engine maintains many technical solutions and constructive elements adopted for a previous prototype derived from a Diesel automotive engine, then converted in a spark ignition unit. The same has been modified in order to be multi-fuelled and compliant with different blends of methane, LPG, and other mixtures of combustible gasses deriving from biomass conversion. This last aspect asked for deep modification of the unit itself, if compared to previous prototypes, but gave a clear flexibility in terms of different fuels. The electric generator is a permanent magnet generator fed by a simple inverter which is a good solution for islanded systems.