Increasing self-sufficiency in a micro grid: integrated vs. non-integrated energy system approach

In a power system with a great share of renewable energy sources (RES) a high degree of self-sufficiency in a micro smart grid might reduce grid extensions in higher voltage levels, because generation and demand are met efficiently and locally. The necessary components must be sized optimally to ensure a cost-efficient micro grid. Existing algorithms size mostly storage systems or combined heat and power units to accommodate a specific installed capacity of renewable generators in a micro grid. Moreover, either an integrated or non-integrated approach is investigated. Hence, in this paper both approaches are compared based on three RES scenarios and the degree of self-sufficiency in a city district of a town in Germany. The comparison shows that both approaches are not profitable in today’s market conditions. Yet, it is shown that the non-integrated approach is suitable for small degrees of self-sufficiency, whereas the integrated approach is preferable at higher degrees.