Half of German PV installers offer batteries

In a new survey of tradespeople, German solar lobby group BSW found that half of German installers have already built a solar roof with a battery storage system, not only among homeowners, but also in the commercial sector. But that does not mean that half the arrays now being installed have battery storage, nor does it mean that PV + batteries is what the energy transition needs.

Germany has never had net-metering, but a few years ago it rolled out a policy called "own consumption" that could be thought of as a kind of real-time net-metering. You cannot simply have your meter run backwards and forwards; instead, you have to actually consume your solar powered directly without exporting it to the grid at all.

As I explained back in 2010, when I criticized the policy for unnecessarily focusing on solar, the policy would inevitably be popular among businesses for one simple reason: they consume most of their power during the day. Homeowners are generally at work during the day, when their solar roofs produce the most, so they need large battery systems to move beyond 30 percent own consumption. In contrast, commercial buildings can go much further, such as 80 percent own consumption for this firm in northern Germany.

Yet, that firm does without battery storage altogether. You see, though the BSW does not explicitly say so in its press release (in German), PV plus battery storage is currently a hard sell in Germany; the combination generally does not pay for itself. The press release implicitly says as much by mentioning the special low-interest loans that can be provided, and adds that "more than 700 loans have been applied for" since May 2013. But in May alone, some 11,500 PV arrays were connected to the grid according to the official spreadsheet (XLS). It's not a scientific comparison, but it does suggest that around 95 to 98 (if we throw in June) percent of solar arrays currently being built in Germany do not have battery systems.

The BSW says that the shift towards PV in combination with battery storage is the result of solar now costing almost half of the retail rate; the highest new feed-in tariffs are now below 15 cents, whereas retail power rates are around 27 cents on the average – and that gap only widens. In fact, that gap is a reason to install solar, but not necessarily to install PV + battery storage, which still does not pay for itself without further incentives.

Overall, the policy of "own consumption" remains, as I argued in 2010, a good idea, but for all kinds of renewable power, not just solar. And in providing additional incentives for solar power storage, it also adds an extra costs. And as I recently explained, Germany focuses on storing solar power so much simply because it is the path of least resistance; solar investors are willing to play around with new technologies. What the Energiewende needs, however, is not stored solar power, but stored power. (Craig Morris)