This story was originally produced by the New Hampshire Bulletin, an independent local newsroom that allows NHPR and other outlets to republish its reporting.
Proponents of a bill to regulate “plug-in solar” in New Hampshire believe the devices would democratize access to the solar energy shining on the Granite State in a time of energy uncertainty. But they also want to tread carefully, they said, to avoid potentially dangerous pitfalls.
“It really is meant that people who might not be covered by community solar, or might not own a house or be able to afford heavy rooftop solar, that they can have some opportunity to generate power and to save some money,” said the bill’s sponsor, Dover Democratic Sen. David Watters, on Monday.
The devices, also called “portable solar,” consist of standalone solar panels that can be plugged into a wall outlet. They feed electricity back into the home, offsetting some electricity use.
Watters said the bill was a question of ensuring personal freedom in energy choices for New Hampshire residents. He noted that the legislation would also make official certain safety requirements for the systems, whose “plug and play” model could pose electrical risks, especially in homes with older wiring.
“This provides a certain amount of freedom, that we value in the state, for people to produce their own electricity and immediately reduce their costs, potentially,” Watters said at a hearing before the House Committee on Science, Technology, and Energy on Monday.
Catching on stateside
More than a million portable solar panels are registered in Germany, the “birthplace” of the technology, according to the nonprofit Solar Power Europe. The true number of units in use there is likely higher, Watters said, because not every user registers with the government.
In the U.S., Utah became the first state to approve plug-in solar regulations a year ago. Now, other states across the country and the Northeast are following suit. On Monday, Maine Gov. Janet Mills signed legislation to regulate the technology’s adoption there.
At a hearing in Concord that same day, Watters said plug-in solar arrays are already available for purchase online, and New Hampshire residents aren’t barred from installing them at their homes. Senate Bill 540 seeks to impose safety regulations on the tech, he said, and chart a path toward broader adoption.
“We want to enable these devices because we think that folks really ought to be getting some sort of clear signal that there’s a safe way to do this and an unsafe way to do this,” said Sam Evans-Brown, executive director of Clean Energy New Hampshire. “As it stands now, this technology really is in a gray area where you can go on Temu and you can grab one of these things, and you might be putting yourself and your family at risk.”
One difference between plug-in solar and more traditional arrays is in how they are connected to a home’s electrical network. While larger arrays are tied in directly, plug-in solar is designed for a wall outlet. Proponents say this is key to the systems’ accessibility, portability, and renter-friendliness, but it also requires some unique safety considerations.
One of these is the importance of making sure the wiring past the plug is not overwhelmed with excess current coming in from the solar generator. Ordinarily, home circuits are designed to trip a breaker if the wires are overloaded with power, but that system assumes the current is coming into the system through the usual route.
If a generator is plugged into a wall outlet, the current it produces could potentially overwhelm the wires away from the breaker, creating a fire hazard without tripping the safety system. This is called “breaker masking,” Evans-Brown said at the hearing.
Another concern is that the generator would continue producing power for a few moments after it is unplugged, creating a shock hazard, or that it would energize the grid if it was not disconnected during a power outage, when linemen are working on wires with the assumption that local power is off.
Some plug-in solar advocates have said that utilities and solar skeptics played up concerns about safety risks to delay the implementation of democratized renewable power generation. But on Monday, Watters and other proponents of the technology said they took those concerns seriously and saw the bill as a way to address them.
Evans-Brown said some groups lobbying for the broad adoption of the systems are “perhaps pushing this legislation in a way that is maybe faster than what is safe.”
Plug-in solar has faced different regulatory hurdles in the United States than in Germany, according to Michael Scherer, co-founder of Houston-based plug-in solar company CraftStrom.
“We quickly realized that each utility is playing by their own rules. They’re all privatized,” he said in an interview. “This is very different than in Germany.”
Nonetheless, Scherer, who consulted with Watters on the bill, has pinned his venture on the belief that the technology will disrupt the solar energy market by allowing residents to bypass interconnection agreements with utilities, usually required for larger solar arrays. This makes solar energy cheaper when it’s captured “behind the meter,” he said.
Some plug-in solar technology comes with built-in features that can prevent breaker masking or excess electricity getting fed onto the grid, Scherer said. But not all of the systems on the market have those features, speakers noted Monday.
Safety restrictions
As proposed, SB 540 contains some safety restrictions intended to prevent dangerous outcomes. Each metered customer would be limited to one portable solar system; that system would be capped at a maximum generation capacity of 1,200 watts, according to the version of the bill passed by the Senate in March. That’s a little more than the amount of power drawn by a typical microwave when it’s actively heating food.
On Monday, Watters and Evans-Brown suggested further restrictions be included in a future amendment. That might include breaking down the category of portable solar into two groups, one below a certain threshold that would be considered safe to plug in at home, while tech above that threshold would require an electrician and specialized plug to set up.
Watters said the bill should leave room for the New Hampshire Building Code Review Board to implement national fire and safety standards for portable solar from the organization UL Solutions, formerly known as Underwriters Laboratories, which certifies electrical equipment for consumer use.
Philip Sherman, chair of the Building Code Review Board, said the bill should lean on UL Solutions requirements for safe balcony solar rather than attempting to legislate threshold values.
“They’re the experts on this stuff,” he said.
UL has called for manufacturers to evaluate certain safety solutions, like specially designed plugs and a built-in power control system to monitor output from the generator, that it has said will help make plug-in solar arrays safe.
A release valve for high electric bills
Broadly, Watters said, the systems would allow users to lower their bills by reducing the amount of power they would need to buy on the grid.
If a customer were to generate more power than they use and that energy were fed back onto the grid, however, they might be charged by their utility, he said. Some meters would record that as electric use, leading to a transmission charge, but whether that will occur depends on what kind of meter is installed at a customer’s home, utility representatives said.
“This seems to penalize the consumer with unnecessarily higher bills and reward the energy supplier and distributors with unearned income from billing for power they didn’t produce or distribute,” said Milan resident Gerard Pednault in written testimony.
Utility representatives from Eversource and Unitil said at the hearing they were interested in knowing how many balcony solar units were in use in New Hampshire. That could be accomplished with a voluntary registry, Watters said, though Rep. Kat McGhee, a Hollis Democrat, said that maintaining records and enforcing the one unit per meter limit would be challenging.
Rep. JD Bernardy, a South Hampton Republican, said that property owners like landlords should be able to make the call to exclude such systems from their properties. Watters said he agreed.
The New Hampshire Department of Energy will help communicate the regulations in the bill to the public if it is passed, Watters said. But Rep. Michael Harrington, a Strafford Republican, said he doubted the ability of the bill to make a difference in public safety unless its contents were communicated to the public.
“It’s sort of like we’re, in a way, trying to put the genie back in the bottle,” he said.
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