Here in the U.S. I have a 3.2 kW PV system and am considering a BMW i3 to purchase that has a direct DC charge port. My goal isn't necessarily just to save money, as my PV already produces 110% of what I use. I would like to use the EV battery as an emergency back-up battery. The DC component could redirect to the vehicle when there is a power outage, which currently automatically turns off the DC-AC inverter. Then, a separate, small 1.8kW inverter could run off the DC-DC converter in the vehicle, powering critical loads in the house. This is a simplified version of V2H, which is used by Japan's version of Nissan Leaf after the Fukushima disaster. The vehicle manufacturers (except for Nissan) are slow to use the vehicle battery for anything other than powering the vehicle.