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To ensure both household safety and grid reliability, the next wave of plug-in solar state legislation should adopt tiered wattage definitions and export limits, writes CraftStrom CEO Stephan Scherer.
Stephan Scherer is an engineer and CEO and founder of Houston-based CraftStrom, which develops and sells plug-in solar systems in the U.S. and Europe. He has testified as a subject matter expert on plug-in solar for statehouses across the country.
With the rising cost of energy plus increased demands from data centers, the momentum for plug-in solar is building quickly.
Utah was the first state to pass a law last year allowing residents to plug solar-generating devices into their homes, and Colorado, Maine, Virginia and other states have followed suit in the span of just a few months.
This summer, plug-in solar legislation continued its run. It passed the California Senate 35-1, thanks to the support of Sen. Scott Wiener. Weeks later, bills passed legislatures in both New York state and New Jersey, now awaiting signatures from their respective governors.
The case for legislation – and attention among policymakers and media – has become apparent and urgent. In the states that have passed plug-in solar laws, residents will be able to save between $175 to $340 every year while reducing reliance on fossil fuels.
With most state legislatures taking a summer break, now is the perfect time to have the conversation about the next wave of proposals.
Energy demands continue to increase while the supply of traditional energy sources has become erratic. And, as air conditioners in households continue to run on high for the summer, rising energy bills have already hit home for millions.
The nation’s energy generation and distribution challenges are all too evident. Aging energy infrastructure, coupled with burdensome permitting and interconnection, means that new electrons often look like they are years — if not decades — away from reaching America’s homes and neighborhoods.
That’s why plug-in solar, also known as balcony solar, legislation has become so popular among lawmakers. Empowering individual households, including renters, to generate their own energy without costly construction or requiring utility approval gives state legislators the opportunity to quickly put money back into their constituents’ wallets.
A recent article from the Lawrence Berkeley National Laboratory, published in the peer-reviewed journal, Energies, highlights that utilities “acknowledged that plug-in solar could offer an opportunity to reduce or defer future infrastructure upgrade costs. Plug-in solar has a similar grid impact to utility-scale solar but offers the advantage of being closer to the point of use.”
Like every other new technology, safety questions often come up. In the case of plug-in solar, the issues fall into two different categories: home safety and safety for the utility grid.
In Germany, more than five million households have already installed plug-in solar without a single incident for homes or their energy infrastructure. Germany became the model for Utah’s state law, which was signed last year, pioneering plug-in solar legislation for the rest of the country.
However, due to differences in Germany’s grid and codes, two issues were lost in translation: appropriate wattage tiers for home safety and clear export limitations for grid reliability.
That could lead to resistance from American utility companies or unnecessarily limit energy savings for American households.
To ensure both household safety and grid reliability, the next wave of plug-in solar state legislation should adopt a two-pronged approach:
The 1,200-watt cap in Utah’s plug-in solar legislation — which has since been copied in many other states — is an example of how Germany’s specifications don’t translate into success in America. Ironically, it could limit the overall effectiveness of plug-in solar and give false confidence in home safety.
Simply allowing systems up to 1,200 watts without any safety considerations creates unsafe conditions for the home. Most of these systems are not plugged into a dedicated circuit; instead, they are plugged directly into a socket that shares a circuit along with other sockets in the home, known as a “branch circuit,” which has the potential to overload a 15-amp circuit, creating a home fire risk.
In addition, without a PCS, “breaker masking” — where backfed power can reduce the current “seen” by the breaker while allowing upstream conductors to carry more current than the breaker detects — can still happen within the 1,200-watt limit. In that scenario, a section of wiring may overheat without tripping a breaker.
However, when used with a PCS, households can safely use more than 1,200 watts of energy from a plug-in solar system, so restricting all systems to less than 1,200 watts reduces the effectiveness, and constituent savings, of plug-in solar laws.
The solution for lawmakers crafting plug-in solar legislation is a tiered approach that promotes safe use.
Under this model, a “safe harbor” would be established for systems up to 420 watts, allowing for installation without a PCS while maintaining home circuit safety. Systems exceeding 420 watts would require a PCS for non-dedicated circuits and must adhere to standard NEC regulations for dedicated-circuit setups.
After talking to dozens of state lawmakers across the country, from Hawaii to Maine, the question they always ask is: “Okay, but what will our local utility say?”
They are right to ask. Utilities are the key to our energy infrastructure and the common touchpoint for consumers, regulators and legislators. And issues attached to larger residential solar installations, such as net metering and interconnection authorization, can be inaccurately lumped onto plug-in solar.
The answer often surprises them: Technology within plug-in solar can ensure interconnection safety between a home and the grid, and safety for utility lineworkers in the event of a power outage.
By including language in legislation that limits the export of electricity from the home out to the grid to no more than 400 watts, state bill authors and sponsors can find the sweet spot that addresses utilities’ concerns and still saves residents money. This limitation is congruent with the tiered system. As demonstrated in Europe already, the 420-watt safe harbor tier will never export more than 400 watts, and larger systems would be monitored and limited by PCS technology.
Many utilities are justifiably concerned about the reliability of their aging electrical infrastructure. Plug-in solar creates the potential for millions of households now reversing the traditional flow of electricity from the grid to the home, outside of the utilities’ purview. Requiring that plug-in solar systems limit that flow to a negligible 400 watts can reduce the pushback and accelerate passage of legislation.
The absence of explicit export limits in legislation creates a race to the bottom for cheap hardware that puts both households and the grid at risk, an issue we are already seeing in some states. One potential incident – either at a home or for a utility – jeopardizes safety and the widespread adoption of this clean energy resource.
The building blocks for safe and successful plug-in solar are all here. Now is the time to piece them together, thanks in large part to Utah State Rep. Ray Ward’s successful vision for plug-in solar in his state.
As Jigar Shah and I co-wrote in his LinkedIn newsletter, Accelerating Climate Wealth: “Utah’s 2025 legislation is an important first step. It recognizes plug-in solar as a distinct product category and exempts qualifying systems from utility interconnection agreements when safety requirements are met. The significance isn’t the specific wattage number — it’s the recognition that consumer-scale plug-in generation deserves a different regulatory lane than large export-capable installations.”
And recently, the National Conference of Environmental Legislators outlined three broad provisions for plug-in solar, emphasizing the maturity of the sector and the technology.
Colorado and Maine have already taken the next big steps in their new laws by creating the tiered definitions for plug-in solar, reducing barriers for small systems and underscoring NEC and UL compliance for larger ones. We also suggest following other states and including language that restricts landlords and homeowner and condominium associations from prohibiting households from installing plug-in solar.
Widespread and safe adoption of solar can be America’s cost-saving energy future, as long as state legislators help protect the grid and their constituents at the same time.
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Certain light-duty vehicles have the potential to earn around $3,000 per summer, and school buses $12,000, by enrolling in the state’s virtual power plant, a state program manager said.
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Get the free daily newsletter read by industry experts
We have updated this list to add electric power industry events covering transmission and distribution, affordability, customer service, microgrids and more.
Certain light-duty vehicles have the potential to earn around $3,000 per summer, and school buses $12,000, by enrolling in the state’s virtual power plant, a state program manager said.
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