Economic and environmental cost of self-sufficiency - analysis of an urban micro grid

In this paper we analyze the economic feasibility as well as the environmental ramifications of operating a renewable energy based micro grid for achieving ultimate self-sufficiency. Results show that in the present case ultimate self-sufficiency is neither economically feasible nor environmentally viable due to large overcapacity in storage and generation. Based on the results we propose that economic viability as well as ecological effectiveness of a local micro grid can only be achieved by an optimized combination of storing, curtailing and feeding-in of excess renewable power, all of which should be considered in a new reform of the German Renewable Energy Act (EEG).