Around the world, balconies on residential buildings feature flowers and flags—but in parts of Europe, they now also sport the dark blue rectangles of solar panels mounted on them to generate a decent fraction of a flat’s power. There, “balcony solar,” also called “plug-in solar,” has become an everyday phrase and a mass-market phenomenon.
Credit goes to a combination of liberalized regulations, spiking energy costs after Russia’s invasion of Ukraine, and manufacturers pivoting to satisfy that demand with DIY-ready kits that combine a photovoltaic panel with a microinverter that converts the panel’s direct-current output to alternating current compatible with home wiring.
Some balcony solar setups add a battery to store that power for the night. And they cost so much less than rooftop installations that a resident can recoup their purchase costs in electricity savings in a few years instead of a decade or two.
Powering Up, One Balcony at a Time
“You have PV, then you have a microinverter, and then you have a normal European plug,” Michelle Kreisig, European PR manager for Anker, told me IFA last fall. “You just plug in.”
In Germany, the leading market, more than one million households had registered balcony solar installations as of June 2025—which, since online registration is not strictly required, understates the total installed base by an unclear amount.
No such simplicity has arrived in the US, where almost all state regulations still require interconnection paperwork with a utility before setting up any solar panels at home, and wiring-safety certifications require electricians to do that installation.
So, the same vendors that showed off cheap plug-in solar setups at IFA—for example, Anker exhibited kits that start at €1,197—came to CES last month with cut-down versions that sent their electricity into a battery or, in the case of Jackery’s $12,000-plus Solar Gazebo, an outlet in a physically separate structure.
Renewable-energy advocates have grown tired of watching advances across the Atlantic while American homeowners face expensive rooftop solar installations—made even pricier by Republicans in Congress terminating the Inflation Reduction Act’s tax credits for them.
“It’s not like Germany has any secret sauce,” said Bernadette Del Chiaro, SVP for California at the Environmental Working Group. “These Europeans picked up the ball, did something creative with it, and it’s now high time for the American consumer to do the same.”
Some Paperwork Involved
“Plug-in solar devices should be treated more like appliances than installations,” emailed Kevin Chou, co-founder at Bright Saver, a nonprofit selling and supporting plug-in solar kits that comply with California regulations. “German households have proven that this is safe at scale.”
In a message at the start of our September conversation, Chou described those regulatory constraints as making plug-in solar “possible, if burdensome.” Bright Saver has tested the systems it sells in California and practices a hand-holding approach to customer support, in part to learn from customer experiences and share those insights with utilities.
“These systems are small, smart, and designed primarily for self-consumption—so in practice, utilities have not raised issues with customers using them to date as they’ve been safe and self-consumed,” Chou wrote.
Some more motivated ratepayers have gone ahead and purchased their own setups without asking permission (see, for example, posts in Reddit’s r/SolarDIY).
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“There’s an apartment building two blocks away from my home, and for the past four years they’ve had balcony solar,” said Del Chiaro, a Sacramento resident.
But legislators and engineers are now starting to remove or at least lower those barriers in the US. The first steps have come from state legislatures, starting with Utah, where a law passed last year, H.B. 340, ended the requirement for electric utilities to approve solar installations that generate below 1,200 watts.
That bill has become a template for other states. In California, SB-868 would lift that “interconnection” requirement for any “portable solar generation device” designed to plug into a regular outlet and generate no more than 1,200 watts. In Virginia, HB395 would establish a similar legal category.
These statutes share terms requiring that qualifying plug-in solar systems have been certified by recognized testing laboratories, such as Underwriters Laboratories, to include such safety measures as not sending electricity out of a house and back into the grid during a power outage.
A Framework Under Construction
UL Solutions took an important next step in January when it announced UL 3700, a testing and certification program for plug-in solar hardware.
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“We know that this is not an unsolvable engineering problem,” said Ken Boyce, VP of principal engineering at UL Solutions. “There are ways to deal with this.”
UL is focusing on how to prevent a plug-in solar system from harming the existing electrical wiring in a house, such as by causing it to overheat, and ensure that setting it up is a shock-free experience. “We will make sure that if the plug blades can be touched by a person, there won’t be voltage on them,” Boyce said.
A whitepaper published by UL in January outlines two possible ways to do that: a “unique configuration plug and receptacle” that, like EV charging cables, would shield the live parts, or a “grid-interactive inverter” that would block electricity from flowing until the plug is properly seated in a receptacle.
None of the current systems UL tested passed the sample tests, but Boyce said the organization is ready for manufacturers to revise their hardware and send it in for testing. “We’re open for business; submit when you’re ready,” he said.
Bright Saver’s Chou said the 3700 standard would get UL only halfway there if it does require a new outlet type, which, for most people, would mean hiring an electrician.
“That’s great for safety, but it also means we’re not yet at the ‘buy it, plug it into the outlet you already have, and you’re done’ experience people imagine,” he emailed in January. Chou would prefer to see UL set up an additional standard for low-power plug-in solar—meaning under 391 watts—that he said would allow “a truly DIY, plug-and-play path that could safely use existing outlets.”
Del Chiaro, for her part, said the combination of state laws ending interconnection requirements and UL certification would unlock this category: “Industry will be fast to respond to the demand these bills will create,” she wrote in a follow-up email.
Along the way, there will be some consumer education. A shift in where you get your voltage may also require a shift in vocabulary. In particular, the word “outlet” may look out of date when power can also flow into that socket. As Del Chiaro phrased it: “We’re conditioned to think that electricity flows in one direction.”
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Rob Pegoraro writes about interesting problems and possibilities in computers, gadgets, apps, services, telecom, and other things that beep or blink. He’s covered such developments as the evolution of the cell phone from 1G to 5G, the fall and rise of Apple, Google’s growth from obscure Yahoo rival to verb status, and the transformation of social media from CompuServe forums to Facebook’s billions of users. Pegoraro has met most of the founders of the internet and once received a single-word email reply from Steve Jobs.
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