Vector eyes late-life EV batteries for home storage

Public charging station for electric vehicles in Aucklands CBD.

Vector, the country's biggest power distributor, is investigating ways to use late-life batteries from electric vehicles as a cheap form of energy storage for homes and businesses.

The company has been working with Melbourne-based Relectrify to see how batteries from a Nissan Leaf, the most common EV in New Zealand, would work when combined with smart battery control technology in a home.

Vector says packs of the re-purposed batteries were able to provide about 15 kilowatt-hours of usable energy, at power levels of up to 10 kW. That is enough to power a New Zealand solar home for one or two nights, it said.

Cristiano Marantes, Vector's head of engineering, says the country's growing EV fleet will generate an increasing supply of lithium-ion batteries. Even when they no longer have sufficient energy to power a car, they generally retain up to 80 per cent of their storage capability.

"We have successfully proven that with Relectrify control technology, these batteries can be kept out of landfill and hold significant value for further use," he said in a statement. "This is fantastic from both a business opportunity and sustainability point of view."

Auckland-based Vector, majority-owned by a consumer trust, is investing in solar, batteries and electric vehicle infrastructure to keep up with the rapidly developing technology.

But it is also looking for ways to use that technology to limit the increasing cost of delivering power and gas to one of the country's fastest growing cities.

Vector added more than 11,100 new properties to its lines last year – 22 per cent more than the year before. It has projected it may have to invest almost $2.8 billion in poles, lines and transformers during the next decade as the city's population climbs to 2 million.

Vector is encouraging solar use, particularly with batteries, to try and cap demand on its lines. It is using network-scale batteries to defer substation upgrades and is trialling EV-to-grid charging as a back-up supply for homes and businesses.

Almost half the country's 14,200 EVs are based in Auckland. Nissans account for about 8,000 of the national fleet.

Vector doesn't have a firm plan to build on the trial with Relectrify.

Marantes says the results show there is an opportunity to build affordable power storage to improve the resilience of Auckland's network.

"While this requires some further development towards scaling, the possibility of what we could achieve is really exciting."