Can Plug-in Solar Work in the U.S.?

For U.S. consumers, going solar is usually a major undertaking, involving tens of thousands of dollars, months of logistics, a slew of financing options, and ever-changing incentives.

But in Germany, upwards of a million customers — homeowners and renters alike — are simply plugging in small, affordable solar arrays to standard power outlets. These small systems are, by law, 800 watts or less, a fraction of the size of a typical rooftop solar system in the U.S. Often called “balcony solar,” these panels can live essentially anywhere with sufficient sunlight: on balconies or patios, or mounted on exterior walls or flat rooftops.

But while governments across the EU have simplified regulations to make installation a quick, DIY process, and utility approval little more than a formality — unleashing a wave of consumer demand in the process — the U.S. has so far failed to follow suit. Here, utility regulations prohibit customers from feeding power back into the grid without a formal interconnection agreement, a process that involves lots of time and paperwork.

Utilities in the U.S. want to account for all electricity sources on the grid, since theoretically, even small plug-in systems could have a cumulative impact on local voltage and power quality, whereas in Germany, for example, this is less of a concern. There, plug-in solar-specific policy caps these systems’ generating capacity, and the grid and metering infrastructure has been more extensively modernized to handle distributed energy generation.

Now, however, there are a number of domestic plug-in solar startups finding creative ways to navigate the constraints of the U.S. market. One of them, the nonprofit Bright Saver, announced on Wednesday that it’s raised $500,000 in new funding from TrueVentures.org and a handful of individual backers. The company gets around power export regulations by selling panels with very low wattage. “So we’re talking 200- or 220-watt systems that never backfeed to the grid, because we think close to every typical household will consume that electricity immediately, simply with the refrigerator,” Cora Stryker, the company’s co-founder, told me.

The San Francisco-based startup has sold a couple dozen systems already and has a waitlist of about 1,500 people, Stryker said. So far, she told me, the majority of this “early adoption crowd” is mainly interested in reducing their own emissions. “We think that’ll change over time,” she said. “The mass adoption in Germany has been driven not by that climate-conscious crowd, but really people who want to save money.”

The main drawback to Bright Saver’s approach, however, is also what makes it possible in the first place: the panels’ incredibly small size, which can’t come close to covering a home’s full power needs. So while the upfront cost of a 200-watt panel is small — $399 at the moment — a customer’s energy savings will also be tiny — potentially on the order of just a few bucks per month. Depending on the location, the savings will eclipse the total cost in about five to 10 years, Stryker told me.

That might not be enticing enough to convince a critical mass of customers to jump onboard the small-scale solar train. But Stryker thinks that getting these products out into the world will help catalyze the type of curiosity and interest that can dovetail into policy change. “Selling product in the next year or two is a small revenue stream for us, but it’s also our theory of change,” she told me. “These need to get out there in order for people to know they even exist.”

Much of Bright Saver’s work involves advocating for easing plug-in solar regulations, which is already starting to happen, bit by bit. In March, the Utah state legislature unanimously passed a bill creating a new category for “small portable solar generation devices” under 1,200 watts, exempting them from interconnection requirements. Stryker told me that Utah’s governor was inspired to introduce the bill after reading a story in The New York Times about balcony solar’s success in Germany.

Now more states, including Vermont, Maryland, and Pennsylvania, are expressing interest in similar legislation. If just a few more get onboard, Stryker told me that would be a critical tipping point. “We’ve had conversations with manufacturers and investors who tell us straight up, they’re not coming to the U.S. market because they see only one state where they’re not going to run into these regulatory concerns,” she said. “They tell us privately, five to seven more states and they’re in. So that’s a key threshold for us.”

But one veteran of the plug-in solar market, Craftstrom, isn’t betting on this happening. The company has been selling 400- to 800-watt systems in Europe since 2017, and expanded into the U.S. a few years later, targeting markets where electricity prices are highest, like California and the Northeast. To deal with domestic regulations, the company patented a new type of meter to be placed inside electric panels that blocks excess power from flowing back into the grid. This prevention mechanism also allows the company to sell larger systems — up to 2,000 watts — in the U.S.

Craftstrom’s chief revenue officer, Ken Hutchings, thinks this type of system is critical for grid safety in the U.S., where distribution networks tend to be older and less standardized than in Europe, and not necessarily built for two-way power flow. This opens up utilities to a good deal of legal liability in the case of equipment failures.

While Hutchings wouldn’t necessarily be surprised to see other states following Utah’s lead, he’s skeptical that the U.S. will become a haven for plug-in solar anytime soon — or even that it’s a good idea. “There’s no risk to one or two guys pushing power back into the grid,” he told me. “But when you have thousands and thousands of people doing it, tens of thousands, and the electric company is not sure who’s doing it, I think that’s where the issue lies.”

Thus far, Craftstrom has sold about 4,000 units in the U.S., with about 500 of those orders coming in the past month alone, Hutchings told me. He attributed the sudden uptick largely to a rush of customers trying to qualify for home energy efficiency tax credits — which he said Craftstrom’s systems are eligible for — before they expire at year’s end.

Craftstrom’s domestic prices are still more expensive than what its own customers in Europe can expect to pay for similar systems due to the extra hardware costs that come along with the specialized meters, as well as the fact that installing these products is not a DIY operation. That means Utah customers should now enjoy the same price relief, since the new state law lifts the grid restrictions that the rest of the U.S. faces. These days, Craftstrom’s more complex hardware plus the cost of labor “just about doubles the cost from what you’re able to get in Utah,” Stryker told me.

Bright Saver sold Craftstrom’s systems when it first started out earlier this year, but chose to discontinue this offering as it “didn’t serve our vision of making this accessible to everyone through cost and self-installation,” Stryker told me. Instead, the organization is focusing on policy changes that will make cheap self-install systems in the 800-watt range feasible in more states. And that means getting legislators onboard with some degree of deregulation, something Stryker acknowledges “has often been a dirty word” in the environmental movement.

“In this case, we need these regulations to get out of the way. They’re outdated. They’re artifacts,” she told me, referring to the requirement that small plug-in systems sign utility interconnection agreements. “I see it as a purple narrative, one that can appeal to values across the political spectrum — energy independence, energy affordability, renters’ rights.”

Of course, Stryker isn’t advocating for complete anarchy in the space. Grid stability is still a concern, and she said that Bright Saver is involved in discussions with regulators and standard-setting bodies to determine acceptable wattage thresholds. Countries that have embraced balcony solar in Europe have “impeccable” safety records, Stryker told me, enabling Germany to raise its wattage limit from 600 to 800 watts at the beginning of last year.

There are still some logistics to work out though. As the recent Utah law is written, plug-in solar arrays must comply with product standards from Underwriters Laboratories, a safety certification body. And while this organization has standards covering the individual components of plug-in solar systems, it has yet to create a systems-level standard. Depending on whom you ask, that might mean all domestic companies in the space are operating in a bit of a regulatory gray area at the moment.

Stryker told me she expects these system-wide standards to be released soon though, ideally in tandem with more bills like the one passed in Utah. “We think it’s a no-brainer.”