Ecotricity founder Dale Vince has said the SunEdison domestic rooftop business it purchased earlier this month is the “missing piece” in the company’s jigsaw.

The green utility announced the purchase last week just hours after SunEdison filed for bankruptcy in the US, however the deal was actually concluded earlier this month.

Ecotricity’s interest in the SunEdison business first started late last year according to Vince but, speaking to Solar Power Portal, he said the utility’s interest in domestic rooftop solar has actually been far longer standing.

“We were planning to launch something before the latest mad cuts came in about 12 months ago and for us it's [the SunEdison acquisition] a kind of a foothold. It's some operational experience while we wait for technology prices to catch up, and we'll relaunch some form of home solar offer for our customers,” he said.

Ecotricity intends to run an operation similar to how it offers onshore wind generators to large businesses on a PPA basis, which culminated in the launch of BritWind last year. Businesses partner with Ecotricity, the utility installs and retains ownership of generation equipment and the business benefits from cheaper electricity than the market rate.

It’s a model Vince refers to as an energy partnership, and one which Ecotricity is keen to bring through into domestic solar.

“It is about working with our customers to help them make their own energy and share the benefits, it's a kind of very modern relationship with our customers as a utility.

“It frees people from the need to find money up front, and from the risk of technology they don't understand and the hassle of operating and maintaining to make sure they keep working for 20 years. All of that worry goes away, and they simply get to use green energy and share the economic benefits of it,” Vince said.

However the company is in no rush to relaunch the domestic offering. Vince said it’s a “wait and see” for the time being and no time frame has been attached. Cuts to domestic feed-in tariffs have made solar a tough sell and the economics are not currently conducive to Ecotricity’s desired model.

Vince is confident that the utility will not be waiting long, noting further projected price tumbles. “Hopefully it's not too long before we can make it work,” he added.

Central to making economics work in the absence of more generous feed-in tariffs could be storage technologies. Ecotricity currently has its own domestic storage product in development and Vince said trials are due to start this summer.

“It's basically a load shifting device, we spent a lot of time studying the grid and what the best size device would be to shift domestic load on and off the grid at different times of the day. It's a very exciting kind of place, but our device is quite special, and we'll be unveiling details of it probably in a few months' time,” he said.