Storing solar power in batteries is an attractive concept to the homeowner who wants to achieve energy independence from the grid, or the commercial and utility-scale solar array owner that wants to hedge against high electricity prices. But right now, the high cost of batteries and the complications involved in setting them up to power homes and businesses has made the solar battery concept uneconomical in all but the most extreme cases — or, for the most wealthy of individuals.
But in some markets, factors including falling solar panel prices, increasing grid power prices and policies and incentives that boost solar installations are starting to shift that equation in favor of energy storage for solar. In particular, Germany — the world’s biggest distributed solar PV market — may be primed for a wholesale shift to battery-backed solar on a large scale.
That’s the view of German solar analysts, experts and entrepreneurs at last week’s Intersolar conference in San Francisco, which dedicated a morning panel session to the convergence of solar power and energy storage. Despite the very real cost and integration challenges involved, “We think battery storage and photovoltaics are a perfect fit, especially if you look at residential and commercial applications,” Intersolar CEO Markus Elsaesser said.
In fact, prior to Germany’s feed-in tariff regime, almost all solar PV in the country was off-grid, according to Dr. Matthias Vetter of the Fraunhofer Institute. That required pretty much every solar installation to have some storage to provide power when the sun wasn’t shining, and those additional costs served as a bottleneck for the sizing and scope of off-grid deployments, he said.
With the emergence of feed-in tariffs in the early part of the previous decade, that situation reversed itself, as Germans were able to sell their solar power back to their utility at guaranteed high prices that exceeded the retail electricity prices they were paying by a significant margin, he said.
But as the country’s feed-in tariffs have slowly gone down in value and the country’s electricity prices have continued to climb, that situation has reversed itself yet again, making the storage option more attractive, he said. Once the price you’re getting for solar via FIT is less than the price you’re paying for electricity, it makes sense to use as much of it as possible at home — or, if the price is right, to store it up for use later.