Currently reading: Renault to repurpose EV batteries into home energy storage systems
Renault has teamed up with Powervault to give used electric vehicle batteries a ‘second life’ as home energy storage units
Jimi Beckwith
2 mins read
5 June 2017

Renault will repurpose used electric vehicle batteries with home energy company Powervault, into a home storage system akin to Tesla’s Powerwall. 

Powervault claims that using former electric vehicle batteries in this way could recede the cost to consumers of a Powervault ‘smart battery’ by 30%. This will help the company on its mission to reach the tipping point of home energy storage ownership in the UK, as the second life packs will start at around £3000; down from around £4300.

An initial production run of 50 units made from repurposed Renault electric vehicle batteries will be made, and supplied to selected homes fitted with solar panels who are customers of M&S Energy, as well as Greenwich schools and some social housing residences. Renault and Powervault aim to gauge the repurposed batteries’ performance compared with conventionally-sourced ones, as well as attain customer feedback. 

Customers with solar panels are being selected, as the packs allow them to store energy collected from the panels, as well as charging at off-peak grid times, allowing the cheaper energy to be used later, when the cost may be higher to use electricity straight from the grid.

Renault claims that the added usage on top of the batteries’ life inside an electric vehicle can more than double their entire life cycle; after eight to ten years of use in EVs, the batteries can be used for around a further ten years in a Powervault. 

Speaking of the recycling process, a Powervault spokesman said: "The batteries are taken back by Renault dealers and removed from cars. Then the car packs are taken apart and the 48 li-ion battery ‘modules’ within it are tested and graded. Those over 70% of their original state of health are then repacked into smaller portable battery packs by Powervault."

"Each pack is 8 modules which gives 2.5KWh of battery capacity. One, two or three of those packs can then be fitted into a Powervault unit in a customer home. Any modules which are below 70% state of health may be found other ‘second life’ homes or recycled responsibly."

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5 June 2017
Question: Why is it cheaper to use electricity at night than it is during the day?

Answer: To reduce peak demand and help spread the use of electricity.

Question: So what happens when demand at off-peak times rise when people are storing their electricity in these batteries?

Answer: There will be no difference between day and night prices.

Is this really the answer to cheaper electricity and efficiency or is it an attempt to justify the expense and inefficiency of EV?

5 June 2017
I suggest you re-read, they’re targeting Solar panel users, so as to store otherwise FREE lost power. ‘armstrm’ explained the finer parts quite well.
As to ‘”efficiency of EV’s” you’re not gonna get more efficient than an electric motor when compared to an ICE, especially in places like Norway where the power source is 99%.
Having explained that, on a non-business level I think it is a little way off for financial reasons and practical reasons, acceptance of EV’s will be the first step.

5 June 2017
No information on the expected life and capacity of these 'used' batteries compared to new ones?

It's no good being 30% cheaper if the capacity is 50% less or the life expectancy is only a couple of years.

Do they come with a good warranty?

Are all used batteries equal. For example if 2 people buy such a system will they end up with the same capacity and battery life expectancy, or couple one system be significantly better\worse than the other?

5 June 2017
As more renewables come on-stream and for that matter even nuclear power, the power will be produced when it is is produced. day or night. It makes sense to use electricity being produced at night by wind farms and other generators that run 24/7 so that we do not need as much daytime capacity. If electricity is not used when produced, it is simply wasted.

5 June 2017
Sounds like a great scheme to get out of the cost and complexity of recycling these batteries with their toxic components - pass it on to some-one else.

5 June 2017
I suggest you re-read it, it says “a further ten years” and then they’re be re-cycled, only this time up to 10 years later. No ploy just doubling their potential life span with the same end of life process.


5 June 2017
People who produce solar energy from their roofs during the day, but use most energy in the evening will be able to use their own "free" energy rather than pass it back to the grid. Scale this up to industrial levels in places like Africa or California and we'll be energy secure.

5 June 2017
I think I saw through @bobbyllew that a company were trying this with Nissan Leaf batteries, but got into problems when the expected degradation rate was too low and so all the cell's remained in cars rather than getting re-used. It would be interesting to know if individual cell's can be tested to see their condition, or if it's the pack as a whole that gets tested.

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