Self-sufficiency and charger constraints of prosumer households with vehicle-to-home strategies

Abstract

In recent years, the market of electric vehicles has been growing strongly. This growth is accompanied by discussions on vehicle-to-home strategies that allow households with a photovoltaic system and an electric vehicle both to charge the vehicle with solar energy and to supply energy from the vehicle to the household. However, vehicle-to-home technology is still not yet widely implemented in prosumer households and there is still little literature about the impact of technological constraints given by the hardware and charging protocols on prosumer energy consumption. To close this research gap, we develop heuristic vehicle-to-home charging strategies that aim to increase self-sufficiency, vehicle availability and traction battery lifetime. We discuss charging power constraints due to technical limitations measured in the laboratory and communication protocols. We investigate the impact of charging power constraints, bidirectional charger capability and forecasting algorithms on the self-sufficiency of the prosumer household. The simulation model integrates a comprehensive electric vehicle model, photovoltaic system model and historic measurement data of prosumer and driving profiles. We propose and simulate three different exemplary mobility profile scenarios. The mobility scenarios differ in their departure and arrival time distributions and are named Worker, Half-time Worker and Late Worker. The developed smart charging strategies can increase the self-sufficiency of the household by up to 16.9 percentage points in comparison to charging the vehicle with maximum power upon plug-in. Decreasing the minimum charging power constraint from 4.1kW to 1.8kW can increase self-sufficiency by up to 10.5 percentage points. Smart charging strategies, the use of a bidirectional charger, relaxation of charging power constraints and the use of forecasting algorithms increase the self-sufficiency of a prosumer household with a photovoltaic system and an electric vehicle.