Plug-In Solar Panels Starting to Sprout in U.S. Backyards

Posted by bookofjoe 20 hours ago

Plug-In Solar Panels Starting to Sprout in U.S. Backyards(www.nytimes.com)

91 points | 87 commentspage 2

plantain 18 hours ago|

This is absolutely insane. This is the most inefficient way imaginable to deploy solar power.

We could deploy 100x the capacity $/Wh with utility-scale farms. Unfortunately we are just completely failing on basic coordination problems like this in the west, every man for himself.

spockz 18 hours ago||

It is inefficient in the grand scheme of things yes. But it is very efficient on the level of the individual home owner, especially if they do not own the building so cannot install solar. It is a good way to cheaply reduce the cost of electricity.

Yes, installing the solar power globally, and getting a globally connected grid would be more efficient in terms of solar panels/kW(h). But alas, that also requires a lot more infrastructure.

In the mean time this can reduce the energy bill for many people. Especially, if tied to a battery. It is not intended to provide independence, for that you need a lot more capacity.

plantain 14 hours ago||

These people are already connected to a grid. We already have the infrastructure.

spockz 7 hours ago||

AFAICT, the Continental US does not have a fully connected grid. This allows electricity providers to charge wildly different rates depending on the state/region. It also requires each net to individually ensure capacity and uptime.

Having a connected grid is a requirement for being able to transfer energy from places with significant amount of renewable energy (solar, wind, hydro) to others. Even if this comes with large losses in transfer it is still a net positive. Especially if you factor in the resulting stability.

triceratops 17 hours ago|||

People buying panels with their own money doesn't take away dollars from utility solar.

plantain 14 hours ago||

It absolutely does. Money (or what it represents) is finite.

Incipient 10 hours ago||

Does $1 on home solar take away $1 from utility solar? Probably not. Does it take away more than $0.00? Definitely.

Who knows if it takes away an amount that actually matters - however in the short term at least it absolutely makes things better for the individual installing them, which is good.

AndrewDucker 16 hours ago||

Nothing about this prevents utility solar

CodeWriter23 19 hours ago|

There was a carport fire in my building back in the 90's. The firefighters got all set up to turn their hoses on it but did not actually start using water to fight the fire until the utility guy from the city arrived to de-energize the supply from a nearby vault.

How does that safety protocol work when the electrical connections and supplies are distributed around the house and may be inaccessible due to fire?

micw 19 hours ago||

In Germany, where this kind of plug-in solar panels is very common (1.5 GW installed power) it is mandatory that the inverter powers itself down as soon as the grid is offline/disconnected. It has to be so fast that you can savely touch the plug after unplugging it. I guess it's standard everywhere.

paulsutter 19 hours ago|||

Actually the rule is that your solar system must stop feeding power to the utility if the utility is down. You are allowed to run in isolated mode if your system supports that. Yes, even in Germany.

analog31 18 hours ago||

Every way I can think it through, isolated mode means your house is disconnected from the utility when you lose power, which requires more equipment than can be contained in a plug in solar panel.

CodeWriter23 16 hours ago|||

Thanks for the answer instead of a downvote.

hdgvhicv 15 hours ago||

The ones I’ve seen tested cut off in half a cycle, even with multiple ones on the same circuit.

Vortigaunt 19 hours ago|||

companies that sell plug-in systems argue that safety risks are minimal or nonexistent. Mr. Scherer of Craftstrom said his company’s systems would not shock electrical workers because they shut off automatically within one second of a power disruption or grid outage.

Mr. Boyce of UL Solutions said his company would certify panels only if they did not pose a risk to consumers or utility workers.

InsomniacL 19 hours ago|||

I imagine the solar panel will detect when the circuit it is plugged in to is de-energised and stop supplying supplemental power to it.

iolo 19 hours ago||

This is exactly how our rooftop solar works. The inverter only supplies ac power if it can sync to the grid frequency meaning that the system disconnects without a live grid connection. Even if I had a battery, this would still be a requirement under local regulations.

KennyBlanken 19 hours ago|||

Maybe the fact that these panels are legal around the world and soon will be legal in a number of US states should be a sign to you that this is not a relevant concern.

0xbadcafebee 19 hours ago||

The device looks for an existing signal from the grid, and if it doesn't find it, it stops feeding power. It even waits for 3-5 minutes before trying again plus some random jitter to avoid thundering herd. It's been a standard in Europe for a while and now finally in the US. This of course depends on the utility and state as not all of them have adopted it but it's quickly becoming the standard everywhere.

IEEE 1547 (interconnection behavior), UL 1741 (inverter product safety), UL 3700 (plug-in solar). (also there are newer revisions you need of some standards like UL 1741)

lokar 19 hours ago|||

Also, utility line workers always treat everything as live until they isolate it and confirm it’s not live (or do the work live in some cases).

amluto 18 hours ago||

I once chatted with some line workers working nearby, and I asked them what they did about residential solar. They said they didn’t particularly care about anti-islanding: if they needed to, they would deliberately short all the customer wires to ground, and if anything hadn’t turned off, then breakers would trip.

t0mas88 16 hours ago||

They even do that to large transmission lines. First shutdown/isolate, then connect to ground or short circuit. If anyone then accidentally turns something back on it will fail immediately.

A few years ago a transmission line in the Netherlands was energized while it shouldn't be, during maintenance work, which resulted in the whole line starting to smoke, sag and spark: https://youtu.be/nyjCrP38ICc

ButlerianJihad 19 hours ago|||

https://en.wikipedia.org/wiki/Balcony_solar_power

  In the United States, Underwriters Laboratories developed the UL 3700 standard specifically for plug-in solar devices, establishing safety specifications for microinverters and connection systems used in these applications.[2] UL-certified plug-in inverters are designed to automatically shut down during grid outages, preventing backfeed that could endanger electrical workers.[7]

So that is the standard failure mode, but do customers understand how it works?

If I had a balcony solar panel, I'd definitely expect it to be providing backup power when we need it the most. I'd expect it to charge a storage battery, not backfeed into the grid.

Surface area means a lot for solar panels. An EV with a solar panel on top is laughable. I own a solar backpack that couldn't charge its power bank within 3 weeks of daily full sun. A "balcony solar panel" may not keep your smartphone charged.

beering 18 hours ago|||

Consumers in Germany generally understand that this is a cost-savings device, not a backup supply of electricity. You tell your neighbors and friends to get it because of the energy bill savings.

They are not as weak as the toy panels you are describing, but they are regulated to 800W max anyways.

0xbadcafebee 15 hours ago|||

The stated purpose for balcony solar is to reduce your power bill. Nowhere does it state it's for backup power. And whether it helps at all depends entirely on your own situation. If it turns out that you can generate, say, 420w for 8 hours, that's 3.3kW, which is a decent amount of power, probably 1/4 to 1/8 the total draw of many homes. That means 1/4 to 1/8 off your energy bill once it pays for the solar panel.

If you want to convert a solar panel into backup energy, there are many ways to do that, but no solar panel+microinverter are safe to just plug into your home. Whether it's a transfer switch, a "solar generator", or a grid-forming microinverter system, they all require you to be physically disconnected from the grid to continue generating power, or to have things plugged into an explicit "backup load" circuit which doesn't come from the grid.