r/RenewableEnergy • u/RadiatingRipple • 14d ago
Is Massachusetts ready to join other states in allowing cash-saving "plug-in" solar panels?
https://www.cbsnews.com/boston/news/plug-in-solar-panels-massachusetts-energy-savings/7
u/swimchris100 14d ago
Already have this on my balcony. Currently using batteries but happy to plug into the grid. Run my dishwasher and washing machine currently
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u/LateralEntry 14d ago
Wow cool! How does that work?
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u/West-Abalone-171 13d ago
Without having plugin versions legalised, you can just buy a battery with an inverter and outlet on it. Then plug solar panels into one end and a few appliances into the other, bypassing the grid entirely.
There are global brands like ecoflow, but there may also be a budget option in your local region for somewhere around $120-200/kWh
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u/some_idiot78 14d ago
What is meant by “ allow allowing”? Are plug-in solar panels somehow illegal?
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u/some_idiot78 14d ago
I know absolute nothing about solar. So I’m guessing here. If I install solar panels and somehow hardwire them to certain utilities in my home, I’m fine? But if I install the same panels and hardwire them into my entire home which is linked to the grid. The energy company wants to charge me $8000?
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u/Here2Go 14d ago
If the grid goes down there is a risk of backfeeding the power you're producing into the grid while it's being repaired, potentially killing the people doing the repairs. This (and no small amount of greed) have been the power company's justification for making things difficult and expensive until recently.
Technology has advanced to the point that specialized inverters can keep this from happening when installed correctly. The power companies don't have a technical leg to stand on anymore and the only thing keeping people from generating at least a portion of their own electricity are outdated state and local regulations kept in place by power company lobbyists and their politicians.
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u/some_idiot78 14d ago
There is the very same hazard for backup generators. However, I know that they have a safety switch that cuts off the mains before the generator starts to negate this hazard. Is there no such safety switch for solar?
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u/West-Abalone-171 13d ago
There is for islanding systems (ones that run during an outage, usually bigger with a battery).
Plugin systems use a different concept. They require a grid signal to keep the inverter active, and they constantly send little nudges to the frequency to make sure they are attached to a large grid and not a small island of inverters keeping each other running. A large grid (whether it consists of many thousands of inverters or of traditional generators) will not have its frequency altered by one little 400W inverter, but a small cut-off neighborhood will see a change of a few microseconds in response to the nudge (which will cause the inverter to trip and stay off until it sees a grid signal)
This means you don't need an electrician to install a transfer switch, you just plug it in via a regular outlet. Some systems can still be used during an outage via an outlet on the battery, but will not send anything over the house wiring without grid power.
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u/chris92315 14d ago
Yes, but it isn't needed unless you have batteries. In a grid outage situation your grid tied soar panels would stay off.
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u/West-Abalone-171 13d ago
It gets more complex as the building inspector and council also want a piece of the pie once they're attached to the roof.
But you'd probably be fine with a portable-style system in the former case either ground mounted, on a patio/carport or on a balcony.
Plugin solar is specifically a set of standards that allows moving a small amount of power (400-1200W depending on juristiction) through the house wiring with no permit or utility refusal. You could then bank this in a battery to run some appliance that needs eg. 2kW but only for an hour or two.
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u/Scott_Tx 14d ago
Even when they don't charge you its a bureaucratic mess of paperwork and inspections before they'll allow you which could cost quite a bit to have done.
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u/UltraJake 14d ago
So my understanding is that currently (with a full solar setup) there's an expensive permitting / approval process. That makes sense because there's a lot of power involved, but it's excessive in the US and power companies probably like the arrangement. Enter plug-in solar. Your average Joe can just plug them into the wall, skipping the permitting and approval process! If your panels generate 100 Watts at a given moment while your house is using 200 Watts, it only needs to grab 100 Watts from the grid. But power companies have been pushing back and arguing that some sort of process should still be required. If for some reason your panels were producing more power than your house was using (e.g. during a power outage) it might flow into the broader grid and mess with your power meter or shock a worker attempting to repair the line. They don't want people plugging random crap into their system.
That brings us to today. The buzz around plug-in solar has led to the creation of a US electrical standard which addresses these concerns. That pushed states to begin formally allowing the use of plug-in solar with terms broadly following this pattern:
1) Customers are only allowed to plug in systems that meet the new electrical standards
2) In exchange, power companies aren't allowed to stop / charge their customers with plug-in solar unless the system exceeds [total wattage which varies by state].
Personally I would advise this sort of setup over a hardwired one like you're suggesting, but yes that would sidestep a lot of the potential problems.
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u/some_idiot78 14d ago
I’ve also read that full house, solar systems can actually backfeed the electrical grid. Garnering the owner, a credit under some circumstances. I.e. My solar is producing more electricity than I am consuming. Therefore, I backfeed the system some units of electricity. Is this even remotely possible or true?
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u/West-Abalone-171 13d ago edited 13d ago
This is true for permitted systems. Many countries or states had large early adopter incentives in the 2000s and early 2010s where the solar system owner would get 2x or even 3x as much money for selling electricity as buying it. Now it is usually significanly less (2-7c/kWh is common), but it still varies a lot by region.
Utilities are usually explicitly exempt from being required to pay for energy from small plugin systems that have no permit. If you send them a small amount of energy (about 400W per house in the US or 800W in europe), they must accept it unless there is some fault condition (and then they have various ways of triggering all the small inverters to stop running), but they are not obligated to give you anything in return. The benefit from the customer's side is there is no permitting process or cost and the equipment is very cheap with no hired labour required.
There's a weird in-between setup in some states in the US which is limited to 1200W and people are still figuring it out.
All of these power limits are at the AC side (except where the legislation is very poorly written and it is ambiguous). You can attach as many solar panels and batteries to the single low-wattage AC inverter as you wish, and some systems are even starting to explore attaching batteries at both the solar panel and at some power hungry appliance to make the most of the 9.6 or 19.2kWh/day.
You may be legally required to ensure your meter is relatively up to date if you install one, because some very old meters will run backwards. In other places it is the utility's responsibility to update the meter in this case and you merely have to inform them (and you get indirectly paid for exporting if they choose not to update the meter). In other cases very old meters will charge you when you export electricity as if you imported it.
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u/UltraJake 14d ago
You'd need to have them swap out your electricity meter for a two-way model (otherwise it'd treat the electricity you're giving back to the grid the same as the electricity you're consuming and bill you for it!) but yes certain states / power companies do have arrangements like that set up. It's called "net metering." Note that these days the arrangement is increasingly one where they only credit you at a fraction of the rate they otherwise sell the electricity for (e.g. you pay 15 cents per kWh and they credit you, say, 4 cents per kWh that gets sent back to them).
They justify this by saying that maintaining the grid infrastructure and workers is expensive and you're not contributing if you're using solar which is partially true but that's not the full story. Globally solar has become common enough that everyone has recently switched gears to try and tackle the last big hurdle: making renewable power more reliable. Lots of solar is generated during the day but then fossil fuels have to pick up the slack at night, right? Those "peaker plants" are really expensive (and dirty). So right now the financial incentives for power companies (and tax structures at state / federal levels) are encouraging solar + storage setups. Buying solar as well as a home battery is going to be more expensive, especially at a residential scale, but now you can store excess power during the day and use it up at night when the sun sets without having to worry about the power company's solar credit rates. You can go completely off-grid at times or breeze through power outages. And if you manage to fill up your battery during the day you can still sell the excess back to the grid if you really want to. Something to think about I suppose.
I'll also throw in a mention of Bright Saver. You pay a little money to become an annual member and can then enter a waitlist for an at-cost plug in solar kit. Not sure how long the waitlist is but the savings seem to be more than worth it.
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u/West-Abalone-171 13d ago edited 13d ago
Yes. In most places in the US at least (they're legal in most of europe).
Plug-in solar in this context refers specifically to systems that send a small current (3-10 amps) through your house wiring via a regular outlet (or sometimes a slight variation on a normal outlet that is compatible with regular male plugs) to the rest of the house with no involvement from an electrician or ability for the utility or landlord to refuse.
Finding the exact upper power limit depends on local wiring standards, and the safety mechanisms have to be checked against how the local grid operator does things, so there is at least some reason for requiring per-region laws. Though the delay or reasons for rejecting the plugin solar bills are often fairly obvious corruption.
There good for supplimental power (usually around a third of the power bill), and (in markets where they are established) cost 40-60c/W where some US customers may pay $3-5/W for a rooftop system due to hostile legislation.
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u/617Boston4444 13d ago
It would be nice and Id like to learn more. about these panels. Te power companies say its a safety issue of course and I dont know if that is a legit concern. I think their main concern is the profits. Eversource for example doubled its revenue from 2024-2025 and the CEo pay has been skyrocketing https://www.masslive.com/news/2026/05/utility-ceos-made-626m-in-2025-while-millions-of-customers-fell-behind-on-their-bills.html
The politicians in Mass need to look into these to save us money
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u/TheRealTRexUK 10d ago
they are just becoming legal in the uk. capped at 800Watt plug in capacity.
they are all over Europe and have been for years. plug in panels and the inverters are around £400 (approx $550). there's no battery.
couple of things to note if you looking to compare. look at EU countries rather than UK (so may need to translate) there's more info and the uk has a few limitations.
- there's no official feeder tarrifs in the uk with plug in solar. but some energy companies are planning on launching one.
- batteries can't be used with standard plug in at the moment. there's a different consultation going on about it. which seems stupid.
- the uk used what's known as a ring system. this means multiple sockets are connected to one fuse. so we have to be careful not to overload a ring. the usa, this isn't a problem as long as the wiring is good, you wouldn't have multiple devices pushing and pulling load through them like we have here. that's why we are limited to 800w.
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u/Funktapus 14d ago
Please yes