Audi has begun investigating using your electric car to power your house. It's not strictly-speaking a new idea – the concept of vehicle-to-grid has been around since the earliest days of the electric car revolution, and Renault also began a pilot scheme in the same area last year – but the German car maker seems pretty keen on it.
Teaming up with electrical networks experts the Hager Group, Audi has put together a prototype bi-directional 12kW charging point, and a special e-Tron electric SUV that can both receive and send power through its charging cable. The system also includes solar panels mounted to the house, and an extra, wall-mounted, 9kWh battery pack which isn't strictly needed to make the idea work, but which just seems like a useful add-on.
Audi’s theory is that electric cars could make the perfect energy sinks for zero-emissions, renewable energy generation. Basically, what happens now, is that when there’s sufficient sun or wind (or both) to provide power to either your home or the grid from solar panels or wind turbines, that power has to be used there and then. If it’s not used, it’s effectively wasted, so if you get high wind speeds or lots of sunshine during a period of low electricity demand, then your renewables are effectively useless.
Storing that energy in the batteries of electric cars is an obvious, and obviously helpful solution. The addition of the bi-directional system means that in a converse situation – where you have high demand but little wind or sunshine – your car could provide energy to your house.
Energy storage
"Electric mobility is bringing the automotive industry and the energy sector closer together. The battery of an Audi e-tron could supply a single-family home with energy for around one week independently. Looking ahead, we want to make this potential accessible and make the electric car part of the energy transition as an energy storage device on four wheels," Martin Dehm, technical project manager for bi-directional charging at Audi told The Irish Times.
So, goes the theory, you come home with a half-used battery and plug your e-Tron into your home wall charger. It’s a sunny day, so the battery begins to be topped off using energy drawn from the solar panels on the roof of your house. Because it’s 5pm (or thereabouts) it’s peak energy demand time (cooking, showering, TV on etc) so your house could also draw on the charge left in your car’s battery to even out the peak in demand. That would not only lower your electricity bill, but you’d get a double benefit of then being able to charge up the car later on, when you’re drawing on cheaper night-rate juice. Another scenario could see a full-charged car being used to power the house all by itself during a power cut.
"Using the battery of electric vehicles to contribute to climate protection while lowering electricity costs at the same time is a vision that we have found fascinating since the very beginning. And we have found an ideal partner in Audi," explains Ulrich Reiner, project manager at Hager Group.
The trick, of course, is to be able to do all of this while not compromising on the available charge in the car, in case you need to nip back out again. Hence the research. “Maintaining mobility is at the centre of our attention. Customers therefore don’t need to restrict themselves in order to make bidirectional charging suitable for everyday use,” said Dehm.
“The intelligent charging management manages the optimum use of the battery, thereby maximising the cost-effectiveness of the overall system. The system is very easy for customers to use – all they have to do is plug in the car, and the rest happens automatically.”
