Germany’s residential storage system maker Sonnenbatterie will continue its push into the US, partnering with Sungevity, the residential PV installer founded by environmental activist and cleantech entrepreneur Danny Kennedy.

Sungevity, which offers upfront payment, loan and financing as well as third party leasing options for its customised systems, will begin offering Sonnenbatterie’s systems to its customers in Europe as well as the US. According to Sungevity, this will start happening in the second half of this year.

While economic drivers and metrics for the desirability of storage systems vary throughout the different regions of the US depending on market design and regulation as well as technical parameters, Sungevity said its customers will benefit by being able to self-consume their solar-generated power and give them access to uninterruptible backup power as well as enjoying “reduced costs”. Backup appears to be a growing concern in the US, with grid outages and recent extreme weather events over the past few years stirring up fears.

Sonnenbatterie’s systems incorporate Sony Fortelion batteries and earlier this month announced that its newest range of lithium-ion storage systems can withstand 10,000 cycles of charge and discharge, adding what the company claimed is a “very long lifetime” to the systems. The German company offers storage units for homes and to some extent businesses as well, launching in 2011. It had sold around 4,000 units in Germany by the beginning of this year, from estimated total sales in the country of around 15,000, giving Sonnenbatterie a big share of the early market.

From there, while PV system sales are on a definite recent trend of decline in Germany’s rapidly changing market, the proportion of systems sold with energy storage attached has risen, as have standalone sales of PV storage. Market research firm EUPD has predicted Germany could see 100,000 household storage systems installed by 2018.

Sonnenbatterie CEO Christoph Ostermann commented on the news this morning, telling PV Tech that the deal fed into the company's "worldwide growth strategy".

"We're happy that one of the leading providers of solar energy in the US has chosen our technology for delivering it to homes. That's a huge step for our worldwide growth strategy but also a tribute to our highly durable and intelligent storage technology," Ostermann said.

For the full version of this story, including insights into the drivers for storage adoption in the US and Germany, innovative new business models and market overview, visit PV Tech Storage.