Cradle-to-gate life cycle assessment of energy systems for residential applications by accounting for scaling effects

This paper addresses the life cycle assessment of renewable and non-renewable energy systems which can be employed for residential applications and provides impact curves which can be used for optimization purposes. A cradle-to-gate life cycle assessment is carried out for the following technologies: solar thermal collector, photovoltaic panel, combined heat and power system, absorption chiller, air source heat pump, ground source heat pump, pellet boiler and hot water storage. For each technology, the inputs and outputs flows of the cradleto-gate life cycle inventory are extrapolated in a range of sizes relevant for residential users. The employed impact indicator is the cumulative energy demand. The novelty of this study consists of a scaling procedure that allows the estimation of the impact of various technologies in a range of sizes and the integration of life cycle assessment for the optimization of complex hybrid energy plants. As an application of the scaling procedure, this paper reports a comparison among some different energy system configurations suitable to residential users. The comparison reveals that the cumulative energy demand of the photovoltaic tends to be noticeably higher than the combined heat and power system for electric installed power larger than 10 kWe.