Solar Storage Technology Upgraded By German Inventor

Originally published on SolarLove.org

Unhappy with any of the available methods of solar storage, a German inventor and engineer has put his favorite pastime of tinkering to good use. While others are attempting to build a better battery, Wolfram Walter is instead building a better way to use the batteries he already has.

It’s not a long stretch of the imagination for Walter. The inventive German has already modified his bicycle and his Porsche, upgrading both of them to EVs. Featured on PRI’s The World, Walter is described as “a man obsessed with things electric.”

The Rising Need For Solar Storage

Living in Umkirch, a small town in southwestern Germany, Wolfram Walter installed a solar energy system on the roof of his house. But, “after just four days,” said Walter, “I was very disappointed about that system. Because it produces a lot of energy by day, (it) is going to the grid, and in the evening I came back, I have to buy it back by night.” But Walter was even more disappointed that he “had to pay more for the electricity he bought back from the grid than he got for the electricity he’d sold to it.”

In the past 10 years, solar energy production in Germany has risen dramatically, with a large portion of the increase due to incentives offered to small producers of solar electricity. But, as Walter explained, “In the moment, if you have solar power you just have power by day.” Because sunshine is only intermittently available, solar storage technology is needed to stabilize and produce a consistent flow of electricity from solar power sources.

The Sonnenspeicher Smart Solar Storage System

Never actually intending to sell his solar storage invention, Walter went to work in his home laboratory to solve his personal solar storage needs. Unhappy with any products he found on the market, Walter started tinkering with a set of off-the-shelf lithium-iron-phosphate batteries.

Designing a system he calls Sonnenspeicher, which is German for Sun Storage, he created a proprietary blend of electronics and software that micromanages the electricity generated by the solar panels, controlling how much power is stored and how much is released to the power grid. The Sonnenspeicher also helps maximize the lifespan of the solar storage batteries, as well as their efficiency.

Solving the intermittency problem, the Sonnenspeicher is described as “a metal box about the size of a small refrigerator.” As Walter explained, “Hook it up to solar panels on your roof and you have a power plant working 24 hours day, 365 days a year.”

While the smart battery is not a new idea, Walter’s invention won a German Innovative Renewables Product of the Year Award in 2013. At that time he was barely a year into the testing phase of his first Sonnenspeicher at home. Less than two years later, Walter is annually selling hundreds of his smart solar storage system to German homeowners and businesses through his new company, Automatic Storage Device.

“This Will Change the World”

Gunther Reidle, one of Walter’s first customers, said that his Sonnenspeicher sits next to his solar power inverter in the basement of his home. He added that he visits his solar storage system several times a day, “just to look how it works, how much energy I saved, how much I collected.”

Reidle reported, “I save about 1,200 euros (~$1,300) every year, that I don’t have to pay to the external network.” It will take around eight years at that rate for his solar storage system to pay for itself. Then he will be making money, and, as Walter believes, this is the key to success for renewable energy technology: “Make it bankable.”

Walter is currently at work on the second version of his Sonnenspeicher smart solar storage system. Smaller in size, less expensive, and even more efficient than the award-winning original version, Wolfram Walter confidently announced, “this will change the world.”