Air Date: Week of October 10, 2025

Balcony solar is designed to be more accessible than rooftop solar. (Photo: Triplec85, Wikimedia Commons, CC BY-SA 4.0)

Compared to traditional rooftop solar, “balcony solar” offers renters, apartment dwellers and folks on a tighter budget a much less expensive solar energy starter kit. Balcony solar is already common in Europe and Asia, and now it’s getting a boost from state legislation in the US. Steve Hegedus, professor of electrical and computer engineering at the University of Delaware, joins Host Paloma Beltran to explain the appeal and how it works.

Transcript

CURWOOD: It’s Living on Earth, I’m Steve Curwood

BELTRAN: And I’m Paloma Beltran.

Rooftop solar can be a no-brainer for some homeowners looking to decrease their carbon footprint, though tariffs and the repeal of federal tax credits have put up extra barriers in recent months. For renters, apartment dwellers or those of us on a tighter budget, rooftop solar may be out of the question altogether. That’s where something called “balcony solar” comes in. Typical balcony solar units start around 1000 bucks and might only shave off 10 dollars a month from your electric bill. But it’s not just about saving money, and the technology is catching on. It’s been widely adopted across both Europe and Asia. And while US legislation permitting its use has lagged behind, a 2025 Utah law now allows residents to install these small-scale solar systems provided they meet certain safety standards. Vermont and New Hampshire have followed suit and have proposed similar legislation. Steve Hegedus is a professor of electrical and computer engineering at the University of Delaware. He’s also a senior scientist at the Institute of Energy Conversion, and he joins me now. Welcome to Living on Earth, Professor!

HEGEDUS: Hi, thank you Paloma.

BELTRAN: So what is balcony or deck solar, and how is it different from other types of solar energy systems out there?

HEGEDUS: Well, the name balcony solar came from the fact that the original concept was to allow people who lived in apartments who maybe had a balcony with a railing to be able to generate a little bit of their own electricity from solar, even though they didn't have a roof that they owned or that they had access to, and by hanging one or maybe two solar modules off their balcony, they could plug the output of the solar panel after it goes through an inverter right into their outlet in their apartment and be able to use the electricity that they made during the day.

BELTRAN: So, it sounds like this technology is pretty renter friendly?

HEGEDUS: Right, and let's be clear, it's not just, I mean, we call it balcony solar because it sort of conveys what it could be. But a lot of the pictures that I see people are installing this just leaning against the house. Or the companies that sell these sell a little rack that is, you know, basically shaped like a triangle that sits on the ground and holds a module up at a fixed angle. And they can be sitting on the ground near your house. Or onto a porch, you know, if you have a first floor porch in your house, you know, I've seen pictures of people mounting them on that too.

BELTRAN: So let's paint a picture here. What kinds of devices can an average balcony solar system power?

HEGEDUS: Well, when the sun's out. And these things don't have any batteries, so they only produce power when the sun's out. If it's producing 600 or 800 watts, that's about as much as a microwave oven, but more typically, the background sort of base line power in your house which is a lot of what's called phantom loads, things that are plugged in, even though they're you don't think they're on, they have circuits that are active. It would power all of those. It would certainly power a lot of the lights in your homes, especially if you have LED lights, it would certainly power all those. It could power a small fan. It's not going to power like your water heater or your air conditioner, things like that, but it could power, you know, any of your smaller appliances when the sun was out at peak times. My feeling is that there's going to be two types of people or families who go in this direction with this plug in solar. It's going to be people who like the idea of energy independence. Are going to be able to make their own power do it yourself. I don't need to get inspected. I don't have to hire an electrician. So it's gonna appeal to those people who have that American independence kind of streak, and then it's also going to appeal to the people who say, you know, maybe I don't have a sunny roof, or maybe I don't own a roof because I rent an apartment, or for some other reason, I can't afford a big solar array and all of the work that goes along with that. But I can do something for the environment, I can do something to participate in the green energy movement by doing this little bit for myself and offsetting a small amount of my electric bill with green energy.

BELTRAN: And now, what about the grid? You know, how does balcony solar interact with the grid in the United States?

HEGEDUS: Excellent question. And as an electrical engineer who is very concerned about the impact of any energy technology, but especially intermittent technologies like solar on the grid, this has to be done correctly. We want this to solve problems, we don't want it to cause problems. So the solar electricity generated by the solar module, it goes into a device which is mounted on the back of the solar module, called an inverter. All solar systems that are installed have an inverter. It converts the DC electricity, which is like from a battery, into the AC so that you can plug it into the grid, alternating current. It is done at the same voltage as our grid normally operates at and the inverter is designed so that if the grid goes down, if it does not sense a voltage or a frequency, it shuts off for six minutes, and then it senses again. And if there is still no voltage or frequency it stays off. So in other words, this device will not back feed, that's the term back feed power into the grid unless the grid is fully functioning. So your apartment or your house, if the grid goes down, you're not going to be getting any electricity generated from your balcony solar. This is done to protect the electrical utility workers and other devices that are supposed to have certain functions when the grid goes down.

BELTRAN: And how could this type of technology affect utility companies?

HEGEDUS: Well, these things will never produce more electricity than is being consumed on site and so the chances of running power into the grid, like, for example, my solar array that's going to be on my house, any excess power is just put out into the grid, and I would get credit for that on my electric bill, these things are probably not going to be producing enough to do that. So the utilities are not going to have to worry about them creating a lot of backflow of energy on the grid. And if there is, by chance, any small amount, it's just going to be used by your neighbors, the utility will never see a big outflow of this. And also, the other impact on the utility is it's going to reduce your electric bill, and therefore reduce the amount of electricity that they need to sell you. So it'll cause a small revenue loss for them but until this becomes very, very widespread, I don't think it's going to do a lot.

BELTRAN: So we have this new legislation encouraging balcony solar across a few states. To what extent do you think those laws will actually expand this technology's adoption?

HEGEDUS: I think it will expand it in two ways, for one thing, once this legislation passes, there'll probably be some coverage in the news and people will then become aware of it. I think most people probably just aren't even aware of this. The other benefit is that it codifies or specifies that if you want to do this, it has to be done safely using equipment and technology that has passed various testing certifications. So you're not going to have some off spec, poorly manufactured systems being installed. Now, since you don't need an electrician and you don't need inspection to do this, someone could buy a poorly made system that didn't meet the electrical code here, and presumably no one would know about it, but ideally, the legislation will make it clear that you know it's to your benefit and your neighbor's benefit that you buy equipment that's met our legislated minimum requirements in terms of safety and reliability.

BELTRAN: And we have an administration in the US that's really pushing back against green energy in general. To what extent does the emergence of this technology give you some hope for the future of solar?

HEGEDUS: Yeah, that's a really good point, because it's legislated by the states and your listeners, I hope should know that we really don't have a lot of energy policy at the federal level. Most energy policy innovations and barriers are implemented at the state level or even the county or utility level. So what this allows, or what this technology allows, is states can enable it, say that it's, you know, it's legal. And the fact that fairly conservative states like Utah and New Hampshire are already supporting this, I think, speaks to that first type of person who would get this, somebody who wants to have a little bit of energy independence. And the other thing is that, since it's do it yourself, relatively low cost I could see where a lot of people who would have wanted to go with a bigger solar array, but they could only have afforded it with the federal tax incentive, which is now gone, that they'll go this path instead, won't be nearly as satisfying to them, they won't be generating nearly as much electricity or offsetting their bill or offsetting as much carbon, but it's better than nothing.

BELTRAN: Steve Hegedus is a professor of electrical and computer engineering at the University of Delaware. Thank you so much for joining us.

HEGEDUS: Sure, I really enjoyed it.

 

Links

Read the Utah legislation

Read more about Dr. Steven Hegedus

AP News | “Solar Panels That Fit on Your Balcony or Deck Gain Traction in the US”