What if getting solar for your home was as easy as going to the store, buying a solar panel, and then putting it in the sun and plugging into an outlet?
That’s the promise of plug-in solar, a form of small-scale power generation that’s taken off in Germany.
German households have installed over 1 million plug-in solar units. They’re especially popular with renters in apartments, who hang them off their balconies — hence another common name for the equipment, balcony solar.
Cora Stryker wants to see the same broad adoption of plug-in solar in the United States. She’s the co-founder of Bright Saver, a Bay Area nonprofit dedicated to the promotion of plug-in solar.
When Bright Saver started in 2025, Stryker and her colleagues were hoping they could get a hundred households in the Bay Area to install plug-in solar.
“We imagined starting a movement and starting really small. We wanted a proof of concept [to] show that people want it,” Stryker said.
A year later, the plug-in solar movement has momentum far beyond what Stryker envisioned.
Movement to expand access to renewable energy
More than half of U.S. states, including Hawaiʻi, are considering new laws to spur the use of plug-in solar.
Stryker said this technology has the potential to help people who have been excluded from the residential solar market — people who don’t own their own roofs or don’t have the money to invest in a bigger system.
“I think this is an incredibly exciting, powerful way for people to take control of not just their energy costs, but also to do something about climate,” she said.
Stryker hopes that state lawmakers and manufacturers can keep up with growing consumer interest. But the U.S. can’t simply copy-paste Germany’s success with plug-in solar.
“Technology has to be adapted to our different electrical system. We're on 120 volts. A lot of the rest of the world is on 230 volts. So you can't just order the systems from Germany,” Stryker said.
Right now, plug-in solar made for the U.S. exists in a bit of a grey area. The equipment is designed to be plugged directly into a building’s electrical system through an outlet. Electric utilities have raised concerns that if all the generated power doesn't get used within the home, it could backfeed onto the grid.
“If there's even a chance, you could export one electron to the grid, meaning if you have excess electricity, you're not consuming on site with your refrigerator, your router, your TV, you have to have an interconnection agreement [with your utility],” Stryker said.
She and other advocates see interconnection agreements — contracts that dictate the terms for connecting a device to the grid — for plug-in solar as an unnecessary hurdle. Legislation before Hawaiʻi lawmakers clarifies that units that produce 1,200 watts or less are exempt from that requirement.
But even if such legislation is successful, that doesn’t mean plug-in solar units will suddenly be everywhere. Safety concerns remain a major hurdle to the deployment of plug-in solar.
Utah became the first state to officially greenlight balcony solar last year, but with a caveat — installed solar units must meet safety standards set by Underwriters Laboratories, one of the nation’s oldest and largest product testing companies.
Until recently, UL standards existed for the individual components of plug-in solar units, but not the complete system.
Underwriters Laboratories just released its first safety certification for entire plug-in systems, which may spur more manufacturers to produce the equipment for U.S. customers.
But even with that new certification, some parties are still skittish about safety issues around plug-in solar.
What's the status of Hawaiʻi legislation?
On Tuesday afternoon, the state House Committee on Consumer Protection and Commerce deferred one of two remaining balcony solar bills after the Office of the State Fire Marshal and other fire and law enforcement agencies raised concerns that the National Electrical Code would need to be updated to ensure the safe installation of these systems.
But Stryker contends that passing legislation now is necessary to ensure safety and to bring a burgeoning underground plug-in solar movement aboveboard.
“We know people are already installing their DIY systems. People are going to do this whether or not it's legal,” she said.
“We really have to pass legislation that makes it crystal clear [that] these kinds of systems are safe for consumers, and we should enable them and get out of the way so that companies can develop the safest systems possible to sell nationwide.”
Stryker believes that if legislation and the market do align, buying a balcony solar unit could soon feel like buying any other household appliance.
Hawaiʻi Solar Energy Association Executive Director Rocky Mould agrees that plug-in solar may soon be on the horizon for Hawaiʻi. But he notes that while the bill savings that someone may see with balcony solar are meaningful, they’re at the margins.
“Every little bit helps, but we need bigger ambition,” he said. “It can provide some relief and some bill savings for customers, but it is not a panacea to achieve our renewable energy goals.”
He hopes the state keeps looking at other ways to make solar work for everybody, like redesigning the Community-Based Renewable Energy program.
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