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Varta battery packs of the storage system, shown by Francesco Tondo, Sales Manager VARTA Storage GmbH Photo courtesy of BSW-Solar

Not long ago press trips in the solar business usually went to the newest cell or module factory or to the inauguration of a large free-field PV installation. Times have changed quickly and now self-consumption and the need to better integrate solar power into the grid are the focus.

This is especially significant in Germany, where the government is now supporing the installation of stationary battery storage with new PV installations. This support comes in the form of discounted loans and even the cost absorption of up to 30% of the storage investment by state owned KfW Bank. Upon request, the KfW states that from the start of the program until end of September some 1550 applications for storage systems have been approved with a total credit volume of 26 million Euros and a positive trend regarding the number of pending approvals in October. Compared to the 1.28 million PV systems that were installed by end of 2012 in Germany, their share is still negligible. It will probably not rise significantly in the near future as long as the support scheme does not apply for all existing PV-systems and prices of storage systems range above 10,000 Euros.   

So, curiosity grows as a press tour schedule includes a presentation of the residential storage system developed by Varta Storage and an on-site visit in a private household that has installed the combination of PV and storage to push self-consumption. Before that, regional German grid operator EnBW ODR reported about the challenges of having one of the biggest accumulations of PV systems in the country and how it tries to balance this by a battery storage provided by Varta Storage. The battery producer claims to have developed a modular storage solution in which degradation of one single battery pack doesn’t slow down the entire system, which can be upgraded easily with additional battery packs and which even can be adapted to all possible future battery systems, be it Li-Ion-based or equipped with other technology; and presents demonstrates this on a dummy of its storage system for private homes.

The next tour stop was a spectacle for the neighbors as the coach bus squeezes itself into a dead end, where 35 journalists get out and occupy the cellar of family Elmer, who volunteered to share their one-year experience with a storage system attached to their PV system. Martin Elmer states that with the storage his consumer habits have changed and he shares his excitement when the well-designed load indicator, in which LEDs signal a good harvest and a fully loaded storage at the end of a sunny day. One can imagine why he compares this to harvesting your own fruit and vegetables in the garden. Asked about the significant investment, however, a Varta executive explains Elmer is part of a Varta Storage field test and thus has not acquired the storage system under “normal” conditions. So, regarding the economic feasibility of such an investment in the end, one has to rely on sample calculations provided by Varta Storage. One of them indicates a saving of some 16,000 Euros after a 20-year period when using a PV storage system compared to simply consuming energy from the grid. Additional conditions of the calculation are the use of KfW support, 5,000 kWh energy consumption and an average 5.7%increase of grid power per annum, as well as the FiT benefit during periods where solar power is feed into the grid. The simulation does not show a point when the investment breaks-even.

At the end of the day the journalists are equally excited by the new possibility of self-consumption of self-produced eco-power; and helpless when it comes to judge if this really will make inroads as long as prices are not coming down significantly. The number of 1,550 KfW applications at least, indicates that residential PV storage systems have reached the early adopters and enthusiasts; but will need more time to become standard for all new residential PV systems. Asked about whether he would have put the money on the table and bought the storage system if they weren’t part of a field test, after some hesitation, Martin Elmer said yes.

Photo: The Varta battery packs of the storage system shown by Francesco Tondo, Sales Manager VARTA Storage GmbH

Written by Andreas Breyer, Senior Editor, Solar Novus Today

Labels: energy storage,self-consumption,grid-connected,Germany,residential solar

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