EcoFlow reports storage surge as Germany reaches 1 million balcony power systems registered

Germany is set to achieve a significant milestone this month with the registration of the millionth plug-in balcony solar system, also known as a “Balkonkraftwerk,” in the country. The achievement underscores the rapid maturation of the plug-and-play solar market, which began with solar kits for balconies, often featuring inexpensive modules and microinverters. However, the movement is expanding far beyond the balcony, with a range of mature solutions.

For EcoFlow, its efforts to support the balcony solar system ecosystem with more high-performance options, along with storage, have shaped the market as well.

“We are in exponential growth and we are increasing the speed rapidly,” Arne Herkelmann, regional product manager at EcoFlow, told ESS News. He notes the market is rapidly moving beyond its initial balcony-limited ideas. “If we look back one or two years, the majority of people who had such units were DIY-ers, solar geeks, and people who liked to tinker. Now what we’re seeing is that it’s becoming much, much more mainstream… It’s not a DIY solution anymore.”

Official statistics on balcony solar systems often don’t match actual sales figures. According to the available official data, 975,582 plug-in solar devices were recorded. However, public registration data is usually delayed by days to weeks after installation registrations are filed, indicating that the million mark has likely already been surpassed.

Additionally, several sources, including the consultancy EmpowerSource, estimated that millions of units remained unregistered at the time due to bureaucratic obstacles. Registrations increased, however, when state government subsidies were provided for balcony solar to support uptake.

A surprising insight from EcoFlow’s data is where these systems are being installed. “The funny thing is that we see in our own numbers is that a lot of the buyers of these systems are not living in an apartment,” Herkelmann reveals. “It’s an impressive number of the overall sales that’s going to people that have houses, where homeowners are using the easy-to-install systems for gardens, terraces, and even rooftops.”

“Now that solar roofs have long been standard in residential areas, the solar boom on balconies is now increasingly shaping the image of inner cities. Ever broader sections of the population are benefiting from the solar energy transition,” says Carsten Körnig, managing director of the German Solar Industry Association (BSW-Solar), told pv magazine Germany this week.

Storage booms through pricing, performance benefits

One driver of more mainstream take-up is the integration of battery storage. Exclusive data from EcoFlow’s own sales, shared with ESS News, revealed that the share of its balcony solar systems sold with storage has doubled from 20% in 2023 to 40% in 2025 in Germany. This is partly driven by falling costs for storage, but also a growing consumer desire to maximize self-consumption, and avoid limitations of grid feed-in rules which cap feed-in power at 800 W in the country.

EcoFlow’s new modular battery STREAM balcony power system is designed to address the 800 W limitation by moving beyond simple grid feed-in, using coordinated and distributed storage to supply local appliances directly.

“The whole idea is that people should use the power sockets on the back of the STREAM devices and then place them next to their appliances,” Herkelmann explains. This decentralized approach allows the system to directly power high-consumption devices. While the system charges from the solar panels and feeds up to 800W to the grid, its true advantage is in direct power delivery. “The inverter of the STREAM unit, from the battery, can output up to 1,200 watts, but we can bypass up to 2,300 watts… with that, you can power a washer, a dryer, fridge, whatever you want.” This bypass feature enables even large appliances to be powered without draining the battery, utilizing a combination of battery and grid power. Furthermore, users can connect two STREAM units in parallel to get the full 2,300 watts directly from the batteries.

The demand for such flexible storage options is also boosting sales of standalone batteries for existing balcony solar owners, such as the new AC Pro battery that is compatible with any microinverter on the market. That presents the chance to retrofit storage into an existing system.

“We are selling the AC Pro, which is a pure storage option, very, very well… there’s a big demand for people adding storage to their existing systems,” Herkelmann says. He sees this as a major industry shift: “We do believe AC-coupled storage is becoming a massive trend because you can just place it anywhere in your house. You don’t have to change a single cable.”

Regulation hurdles, and France next

Despite the rapid growth, hurdles remain. Herkelmann points to regulatory uncertainty where political will has outpaced technical standardization. While Germany’s “Solarpaket I” legislation officially raised the feed-in limit for plug-in balcony solar inverters to 800 watts, the corresponding German Association of Electrical and Electronic Devices or VDE technical standard has lagged, creating frustration. “The VDE and others want to finish it for years now and yet it’s still in draft… a lot of people are waiting for a clear definition of what can be done,” Herkelmann says, highlighting the gap between what is legally permitted and the final technical rulebook from the VDE.

Furthermore, official advice has been slow to catch up with market realities, even in Germany. “If you look at the Bundesumweltamt [Ministry of Environment], they are still recommending people not to buy storage for Balkonkraftwerk,” he says. “The problem is that these articles are dated. This recommendation was written when a kilowatt hour of storage was 1,000 euros. And now one kilowatt-hour of storage is roughly 300-400 euros. It’s a completely different game.”

Looking ahead, and outside of Germany, EcoFlow sees strong potential in other European countries, along with the US, where it has also launched a balcony solar system. as well not just in Germany—where an estimated 20 million households could install a system—but across Europe.

EcoFlow told ESS News that France currently ranks as the second-largest balcony solar market behind Germany, indicating that the chance for the plug-and-play solar revolution could be more widespread with regulations.