Audi takes leaf from Nissan, pursues vehicle-to-grid EV charging

German luxury car maker Audi is taking a leaf from Nissan’s EV book, announcing it is exploring the use of electric cars to charge homes and help ease demands on electricity grids.

Audi plans to introduce 20 all-electric models by 2025, so a focus on bi-directional charging could put Audi at the forefront of a brave new world where cars and homes work together to supply energy to occupants.

The concept is not new: Nissan has been developing vehicle-to-grid (V2G) and vehicle-to-home (V2H) technology for some time and its new Nissan Leaf is approved for bidirectional use on Japan and other countries and is expected to be approved in Australia before the end of 2020.

Aside from the great benefits in times of emergency, V2G and V2H (known collectively as V2X) have the capacity to reduce demand on the grid and earn revenue, something a world-leading trial to be conducted by the Australian National University will seek to assess.

Germany is already drawing 50% of its power from renewables during the first half of 2020, so the potential of V2X is clearly not lost on Audi.

Initially, Audi and German electrical giant Hager will work on storing excess energy generated by rooftop solar in electric car batteries, which can then be released when required.

The principle is scalable to larger dimensions: as renewable energy sources claim an increasing share in electricity generation in the overall network, the surpluses can be “mopped up” by electric vehicle batteries, and in times of low energy generation or peak demand they can discharged to the grid to help meet demand.

“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,” said Martin Dehm, technical project manager for bidirectional charging at Audi in a statement.

“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.”

“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,” said Ulrich Reiner, project manager at Hager Group in a statement.

The technology has been best demonstrated in Japan, where Nissan supplied 66 Leafs to help homes and businesses bereft of power – a move which not only assisted people at a time of great need but also gained Nissan’s offshoot 4R Energy an award from the 2020 Japanese Resisience Awards.

Late model plug-in hybrid Mitsubishi Outlanders also have the technology, although with their smaller batteries their use cases are somewhat more limited.

For both these vehicles, the bidirectional charging capability is made possible by the CHAdeMO charging plug standard, although Nissan’s newest EV, the Ariya SUV, has signalled that the CCS charging plug standard used by European car makers will also be able to be used for V2H and V2G – eventually

In Audi and Hager’s test, the project used an Audi e-tron, which commercially comes with a 71kWh or 95kWh battery depending on the variant, kitted out with near-series charging technology.

An additional 9kWh home energy storage battery was also used, and though Audi notes this is not a requirement for V2X charging, it hints that it may offer this as part of a future series production option.

Notably, the trial used a DC wall box with a maximum charge rate of 12kW – homes will typically have AC chargers – meaning an inverter was not required for the trial and resulted in “a particularly efficient solution,” according to Audi.

The intelligent charging management manages the optimum use of the battery, thereby maximizing 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.”

How it will transfer its DC trial over to AC wall boxes for home use was not made clear.

The announcement is promising as a step towards more car makers embracing the potential of V2X technology, but along Audi boss Markus Duesmann’s recent comments that the car maker will continue to invest heavily in combustion engines, it does send a mixed messages.