The economic potential of grid defection of energy prosumer households in Germany

Abstract

The fast decline in solar photovoltaics (PV) prices has brought grid parity or near grid parity to household systems, with alternative energy sources generating power at a cost less than or equal to the price of the power from the electric grid in many countries. This price decline, together with a reduction in battery prices, has prompted new societal, scientific, and political discussions about the possibility of installing a PV-battery system and “unplugging from the grid” or “living off-grid.” We present a new decision support model to assess the economic feasibility of defecting from the grid. In addition, a sensitivity analysis is carried out for critical parameters such as technology costs, different load profiles, and feed-in tariffs (FiT). From an economic perspective, a widespread of autark households do not seem to be a realistic projection of the future. Our findings indicate that, for Germany, leaving the grid is not the best economic choice, and that retaining the grid connection could be more profitable by simply minimizing the electricity purchased from the grid and installing an optimized size of the PV-battery system. The system's financial feasibility can also be achieved with new forms of energy negotiation, such as peer-to-peer (P2P) trading or household clustering, allowing prosumers to sell their excess energy locally as an alternative to grid feed-in.