A multi-objective analysis of grid-connected local renewable energy systems for industrial SMEs

Frieden, Florian; Leker, Jens; von Delft, Stephan

Abstract

Owing to the intermittent nature of renewable energy, complexity of battery systems, and various factors affecting investment decisions, the comparison between renewable and non-renewable energy systems is challenging. This study addresses the multi-target problem of local renewable energy systems comprising photovoltaics, wind turbines, batteries, and a power grid connection for industrial small- and medium-sized enterprises. The applied multi-objective analysis considers four dimensions (self-sufficiency, costs, lifecycle emissions, and land consumption) to optimize the combination of components of the energy system and describe the trade-offs. This study extends prior research, which primarily focused on energy and cost parameters for residential applications. Our findings are Pareto fronts of the optimized combinations of photovoltaics, wind turbines, batteries, and electricity procurement or sale. Using a manufacturing facility in Germany with a 5 GWh electricity consumption to test the model, the results show that such a manufacturing site fully powered by renewable energy is approximately 22 % more expensive than the conventional case. However, implementing renewable energy in a company's energy system for an extent of 60–70 % of its electricity consumption can reduce energy costs and emissions by up to 27 % and 60 %, respectively. If excess electricity is fed directly into the power grid at a high price, a cost advantage can be generated. Overall, the results suggest that these four objective dimensions should be considered simultaneously to guide investment decisions.