Why It Matters
Plug-in solar panels that attach to balconies and feed power directly into household outlets offer renters and apartment dwellers a path to renewable energy that traditional rooftop solar cannot reach. Maine and nine other states have legalized the technology in recent months, but regulatory hurdles and the absence of completed safety certifications are slowing the US market’s development.
What Happened
Balcony solar—also called plug-in solar—allows homeowners and renters to install small photovoltaic panels on balconies, patios, or walls and connect them directly to standard electrical outlets to offset utility bills. The technology originated in Germany in the late 2010s and gained momentum after Russia’s 2022 invasion of Ukraine, prompting European households to seek energy independence.
Utah became the first US state to legalize plug-in solar last year, followed by Maine and nine other states that passed enabling legislation in recent months. Several additional states are considering similar bills. However, the market faces a fundamental obstacle: American electrical systems differ sharply from European infrastructure, making German products incompatible with US outlets and codes.
A handful of companies are adapting products for the US market. CraftStrom, which launched in Germany in 2019, has been selling systems across all 50 states for several years after redesigning its microinverters and panels to meet US grid parameters and safety standards. EcoFlow has reengineered products for US conditions beginning in Utah, adding software that enforces state-specific requirements. Bright Saver, a newer entrant, began selling plug-in panels on its website earlier this year and recently cut prices to sell kits at cost plus a membership fee.
No complete plug-in system has yet received official certification from UL Solutions, the standards-testing organization, though testing of full setups began in January. The National Electric Code is undergoing a multiyear revision, with the 2029 edition potentially creating pathways for broader plug-in accessibility.
Cora Stryker of Bright Saver explained the design challenge: “We unfortunately can’t take one of those systems from Germany and bring them here and plug it into the wall, because we just have a different electrical system.” Stephan Scherer of CraftStrom noted that early market experience in Germany proved valuable: “The good thing about the German market was that we got to play around, test, improve in time for the U.S. market to start.”
By the Numbers
4 million — Balcony solar systems installed in Germany as of 2025
1 million — Systems officially registered in Germany
10 — States that passed plug-in solar laws in recent months
360 watts — Safe power level for any standard outlet plug-in
$285.30 — Cost of 180-watt Bright Saver kit at discounted at-cost pricing
$414.17 — Cost of 360-watt Bright Saver kit at discounted at-cost pricing
Zoom Out
Balcony solar reflects a broader shift toward distributed renewable energy and decentralized power generation. Germany’s experience—where roughly one-quarter of installed systems remain unregistered—shows both the technology’s rapid adoption and the regulatory challenges nations face in integrating small-scale solar into existing grid infrastructure. The US residential solar market has long been dominated by rooftop installations managed by large providers, most of which have not yet entered the plug-in segment. The delay in UL certification and the fragmented state-by-state regulatory environment may keep plug-in solar a niche product until national standards solidify.
What’s Next
Certification testing will continue through at least 2029, when updated electrical codes may clarify safety protocols and expand market access. Maine’s recent budget approval and energy initiatives could accelerate adoption in the state. Manufacturers are expected to continue refining products for US specifications, and additional states may follow Maine and Utah in authorizing plug-in solar, though widespread rooftop solar providers have not yet signaled plans to enter the market.