German battery maker puts squeeze on Tesla's solar storage plans

November 26, 2015 // By Paul Buckley
German battery maker Sonnenbatterie has launched a scheme to connect households with solar panels and other consumers to improve the distribution of surpluses of the renewable energy and help members to become more independent of conventional suppliers.

The 'sonnenCommunity' scheme, which aims to boost demand for the start-up company's batteries which store solar power, allowing owners to use the clean energy even when weather conditions are not favourable.  The scheme, which poses a new challehge to traditional power supply companies in Germany, also marks a pre-emptive strike targeting U.S. electric vehicle maker Tesla that is also looking to enter the German market and plans to start delivering wall-mounted batteries that can store solar power to Germany in early 2016.

"SonnenCommunity allows all households that want to determine their energy futures themselves the access to affordable and clean electricity," said chief executive Christoph Ostermann.

The initiative comes at a time when battery technology is approaching a point where ordinary householders can afford it.

By storing solar power and releasing it on demand, households can avoid having to buy more expensive power off the grid to supplement their production. The batteries could also help solar power households cope with a phasing out of subsidies currently paid when surplus power is sold to public grids.

The sonnenCommunity combines three technologies: decentralized power generation, advanced battery storage technology and digital networking. A self-learning software platform is used to control the system and connects the individual members of the community.
By monitoring the production and consumption data of the members in real time the platform balances supply and demand. Combining weather and member consumption data creates the basis for a precise prognosis for the expected production and demand within the sonnenCommunity. The cyclical energy input from renewable sources thus becomes calculable and can be flexibly integrated.

Sonnenbatterie claims to have sold 8,500 lithium battery units which the company claims makes it the European market leader.

Germany has around 25,000 batteries in operation that can store solar power - still a small number given there are around 1.5 million solar production units, mostly located on roofs of family homes - but year-on-year sales are growing rapidly.