What You Need to Know about Maine’s New Plug-in Solar Law

A new plug-in solar law passed in April 2026 clears the way for Maine renters, homeowners, and local business owners to take advantage of clean, cheap solar power to reduce their electricity bills. These small, portable solar panels are expected to generate a lot of interest because they’ll give Mainers the opportunity to generate solar power right at home to offset electricity use. 

 Here’s what you need to know about Maine’s new plug-in solar law: 

When will plug-in solar be available to consumers in Maine? Plug-in solar systems won’t be available to consumers until updates to product safety codes and standards have been made. This is expected to happen later this year. By the fall, Mainers should be on the lookout for products that advertise themselves compliant with UL3700.  

What is plug-in solar? Plug-in solar, also called balcony solar, lets a person plug a solar paneldirectly into their home through a standard outdoor outlet, generating clean, renewable energy and reducing the amount of electricity they need to buy from the grid.  

A typical kit consists of between one and up to four to six solar panels, an inverter, and a plug, with the option of a battery.  

The technology has taken off in Europe in recent years, especially in Germany, where there are now a million registered balcony units in use with a combined capacity of one gigawatt—roughly equivalent to the size of two U.S. coal plants. They’re even sold at Ikea! 

Part of the reason for this success is the huge appeal of these systems.   

1. They’re simple. Plug-in solar is small and portable and can be self-installed on a balcony railing, a fence, or in the backyard. They offset only a portion of the customer’s electricity use, so they don’t require an interconnection agreement with the utility that you need for larger rooftop installations.
2. They’re affordable. They are cheaper per watt than rooftop solar, so they lower the bar for renters and apartment dwellers, as well as people who can’t afford the high upfront costs of installing larger solar arrays on their roofs. In Germany, a basic 800-watt (W) kit from Ikea costs around $500. In the U.S., where they aren’t widely available yet, prices are higher, around $1,000-1,500, but are expected to come down rapidly as more states pass laws like the one in Maine.  
3. They help save money. At a time when electricity prices are already high, the war in Iran and our dependency on imported fossil fuels is driving them even higher. According to Public Utilities Commissioner Patrick Scully, more than 70% of Mainers are struggling to pay their electricity bills, and the last five years have seen a 68% increase in Central Maine Power’s electricity rates. For the average household in Maine, a 1,200-W system, which is the maximum size permitted by Maine’s new law, could cut electricity bills by nearly 20% or $388 a year, according to the Office of the Public Advocate.
4. They offer resilience. When paired with battery storage (available now to consumers), they can provide a source of backup power during outages.  

What does the new law do? Mainers can already purchase these kits online, but legally they’d be required to apply for interconnection with their utility to get approval before plugging them in. The new law exempts plug-in solar from these costly interconnection rules intended for larger rooftop installations 10-20 times the size.  

The law prohibits utilities from making their customers get approval, pay fees, or install additional equipment or controls.  

Plug-in solar isn’t eligible for net energy billing. So, any energy sent to the grid—after consumption on-site by the refrigerator, heat pumps, other lights, and appliances in the house—would be minimal, well within the safety margins of utility equipment, and wouldn’t earn generation credit for the customer. 

The law further specifies home safety codes and standards, distinguishing between systems up to 420 W and those between 420 and 1,200 W.  

Up to 420-W kits. Smaller units must be installed in a way that’s consistent with the electrical code for other power generation sources, like backup generators. Article 705 of the National Electric Code may require, for instance, having a dedicated circuit breaker in the main panel. For most of us without technical know-how, we recommend having a qualified electrician certify that the installation is up to snuff to protect your home.  

420-1,200-W kits. For larger systems exceeding 420 W, the law requires that a licensed electrician install the equipment and use a dedicated circuit with only a single outlet. This is a protective measure given the diversity of electrical wiring across Maine’s housing stock.  

One chief concern this provision aims to address is that the plug-in solar device would be back-feeding into a branch circuit, introducing additional current that is not protected by the upstream panelboard circuit breaker. So, if other appliances are on that same circuit drawing power from the grid, the combined current could exceed the breaker’s capacity but go undetected by the breaker, posing a risk of fire or shock. By requiring an electrician for larger kits, the law seeks to ensure home wiring is configured to effectively mitigate risks like these.

Electrical and product safety standards will be specified in UL3700, issued by UL Solutions, an independent product certification laboratory. Importantly, the law requires that plug-in solar of any size complies with these product safety standards, which are expected to be finalized in the coming months. So, after the law goes into effect in July (90 days after the Legislature wraps up later this month), Mainers should be on the lookout for certification of product compliance before purchasing.    

Customers with larger systems exceeding 420 W need to notify their utility within 30 days of installation, to let the utilities track use of these systems within their service territories.  

As a related safety provision, the law also requires systems of any size to have inverters that are configured to shut off after 0.2 seconds if power from the grid is disrupted. This is a function called “anti-islanding” protection that serves to protect utility line workers in the event of an outage. A shut-off time of 0.2 seconds is 10 times faster than current requirements for much larger rooftop arrays and therefore more protective. This can also reduce the risk of touch shock at home if a plug becomes partially unplugged.  

While the 0.2-second standard is in effect in Europe, it hasn’t been incorporated into inverters in the U.S. yet, so manufacturers will need to adjust. It’s unlikely that products currently available online to Mainers satisfy this requirement.  

In 2025, Utah was the first state to legalize plug-in solar. Now Maine, and with more than 20 states around the U.S. considering similar bills this year, more are expected to follow.  

Passing this bill was a true team effort! A Climate to Thrive, Maine Climate Action Now, and the Natural Resources Council of Maine worked together with other partners in the Environmental Priorities Coalition to get it done. 

With demand in the U.S. set to surge, prices are poised to come down steeply to E.U. levels, as local retailers start stocking their shelves. Now Mainers will be well positioned to make their own energy decisions, reduce their high electric bills, and take direct advantage of the cheapest energy on the planet.   

—Rebecca Schultz, NRCM Senior Advocate, Climate & Clean Energy