Balcony Solar and DIY Clean Energy

Galen Nelson
Welcome to my guests, Juergen Weiss and Cora Stryker, and everyone joining today on Thoughtful Climate, MassCEC\'s speaker series, where each month we highlight experts, pioneers, and practitioners from a variety of existing and emerging climate tech sectors, as well as subject matter experts who can provide insights into broader economic, social, and technological dynamics shaping the climate tech industry.

Galen Nelson
Today, we are talking about balcony solar, and we will touch briefly on a new class of through-window heat pumps as we explore what appears to be a rapidly growing homeowner interest in DIY clean energy. Before I jump to my guests today, Cora and Juergen, welcome. I am going to provide some brief context for our discussion.

Galen Nelson
For the uninitiated, balcony solar, sometimes known as plug-and-play solar, describes a class of relatively low-capacity solar PV systems, typically around two panels, usually around 800 watts, which, as the term suggests, are designed to fit on a balcony, porch, or deck, or even in your backyard. Unlike conventional larger-scale ground or roof-mounted systems, which are hardwired and much larger, you merely plug these miniature solar systems into a 110 outlet. Balcony solar systems first started gaining traction in Germany about eight years ago, when the VDE, a German certification body that issues product and safety standards for electrical products, released the first guidance that allowed for balcony solar systems to flourish. Two years later, Germany created a universal online registration system for plug-in solar, and that further increased market adoption.

Galen Nelson
Balcony solar is just beginning to gain some traction here in the U.S. Today, we are going to talk a bit about what it will take to accelerate market adoption for this exciting new solar deployment option. What is driving interest here? Likely a mix of forces: energy affordability, growing consumer interest in DIY projects, and widespread interest in making a positive climate impact. A bit of housekeeping before we start and before I jump to Cora and Juergen. Feel free to drop questions in the Q&A. We will reserve some time near the end and do our best to address those. Let us jump right in.

Galen Nelson
Juergen, Cora, thanks so much for joining me today. This is a exciting and hot topic. I am glad to talk to you about it. Let us start with some introductions. Maybe Juergen, you can lead us off. Briefly introduce yourself and perhaps react to the market drivers I mentioned: energy affordability, interest in DIY, having a climate impact. What excites you most about balcony solar?

Juergen Weiss
Thanks for having me, Galen. I was born in Germany, as the name might suggest. I grew up there, went through high school and a little bit of university in France and in Germany, and then moved to the States for grad school. I have been here ever since, working for the last 35 years, mostly in consulting around electricity markets and the energy transition. I also played professor at Harvard Business School for a few years, where I developed and taught a course on the Global Energy in Transition.

Galen Nelson
You have done some wonderful consulting for the state of Massachusetts.

Juergen Weiss
I have done a fair amount of consulting for the state, primarily for the Attorney General\'s office. I go back and forth a lot and have been observing the evolution and emergence of balcony solar in Germany and in other European countries as well. After thinking about and consulting on renewable energy and the energy transition for a long time, I came to the conclusion that I want to focus on things that radically accelerate, or have the potential to radically accelerate, decarbonization. I have been looking for examples of technologies and ideas that make that possible. It strikes me that plug-in solar or balcony solar squarely fits into that category for two reasons. One, it eliminates the subsidy game, because these things in Germany are so cheap that they pay for themselves in a very short time, without any feed-in tariffs, tax credits, or any other subsidies, just pure economics. That is helpful. The second is that this is incredibly scalable. You can buy them online, on Amazon, at IKEA, at your local Home Depot. You take them home and assemble them and plug them in, as the name suggests. It is a consumer good, a consumer appliance. Consumer goods, we know how to scale making those things quickly. It bypasses the lags that exist in the traditional ways to deploy renewable energy in the United States, where you need plans and permits and inspections and agreements. Both the economics and the fact that they are plug-and-play and therefore incredibly scalable make them, for me, the prototypical accelerator of decarbonization.

Galen Nelson
Thanks, Juergen. That is helpful. In addition to those initial drivers, I am hearing speed to market and accessibility. How about you, Cora? What is your BrightSaver elevator pitch, and what excites you most about balcony solar?

Cora Stryker
Thank you for having me. I am co-founder of BrightSaver. We are the first and only nonprofit in the United States to be single-mindedly focused on balcony solar. We see ourselves as part of a larger clean energy movement, but that is our focus. We are a nonprofit. We started with this vision: clean energy, in particular rooftop solar, is not accessible to every American for a number of reasons. Renters do not own their home and generally cannot decide to put rooftop solar on their dwellings. Some people are owners but live not on the top story, they have no roof. Some folks do not have access to great financing. We started with this vision that the key to rapid energy transition is accessibility, inclusiveness, and equity. At the same time, that addresses energy affordability and inequality across elements of society. You do not want the clean energy transition to be restricted to homeowners who have excellent roofs that are ready for rooftop solar. That was the vision we started with. Initially, we thought the primary barrier is cost. As a nonprofit, we would step in and make this more affordable, subsidize it, and provide financing. However, we learned quickly that cost is a barrier, but not the primary one. The first barrier is regulatory restrictions. We have a white paper out that goes deeply into that. Our focus now is regulatory reform in a critical mass of states. We are told about five small states, or a couple of big states, are all we need to clear the regulatory restrictions to enable the market, to have manufacturers come in. Competition will lower prices. As Juergen pointed out, these pretty rock-bottom prices of German systems are the goal. That is our focus; that is our mission.

Galen Nelson
That is great, thanks, Cora. When I first learned about your organization and checked out your site, I was impressed with the assistance that you were providing, but then immediately saw that you were also working on the policy end, which is thoughtful and critical. It is a powerful combination. I am glad that you are doing that work.

Galen Nelson
I do want to get into some of the safety and technical issues. I think that will provide a solid foundation for our listeners, so folks better understand the differences between balcony solar and conventional systems. I want to stress that, as Juergen noted, in Germany and other European countries that have figured this out, balcony solar is surging, and there have been very few safety issues. We have a different electrical system in this country, both at the grid level and at the building level. We will likely address these safety issues in a different way, but these are solvable challenges. I think we are getting close to solving them. Nonetheless, it is important for folks to understand these concepts. My sense is there are three main issues. I invite you both to correct me or jump in with additional details.

Galen Nelson
The first is that this is an appliance that you plug in, but rather than drawing power, it is generating electricity, so there is a risk of shock when you unplug the unit. While there may be a variety of solutions to address that challenge, my sense of the market is that the dominant solution is the microinverter, which cuts power to the plug within milliseconds when the unit is unplugged.

Galen Nelson
The second is this notion of breaker masking. Some people have asked, balcony solar sounds great, but why limited to 800 watts, which is the current limit in Germany? Why not go to 1200 watts or more? This gets a concern that you could overload circuit breakers with this phenomenon known as breaker masking. Juergen, can you jump in here and help us understand breaker masking? I like the way you discuss it.

Juergen Weiss
The technical term is probably complicated for people who have not read up on this. The way electric systems inside a home are similar in Germany and the United States is you have circuits. You have a box in your basement with circuit breakers. Those circuit breakers are designed to prevent the wires in your walls from overheating because there is too much power being drawn on one or multiple of the outlets on a given circuit. There might be 15-amp circuits or 20-amp circuits in the United States, and something similar in Germany. The breaker is supposed to disconnect the circuit, stop anything if the power line in your house is overloaded. It warms up, and if it is too hot, eventually it melts and burns your house down. It is designed to prevent that.

Juergen Weiss
The masking thing is, if after you install one of your plug-in solar systems, you decide to plug in a lot more appliances downstream of where your solar panel injects electricity than you would normally plug in. If you have two toaster ovens as opposed to one, each drawing 1,000 or 1,500 watts, normally that might overload the circuit, and the circuit breaker would flip. Everything would go dark. If you plugged in one of these plug-in solar things upstream, between your circuit breaker and your two toasters, the solar power would supply part of the electricity for your two toasters. The breaker would only see the difference between what the toaster ovens consume and what you stick in through the solar panels. The breaker might think it is only 1,000 watts, when in reality you are using 2,000 watts. That is the masking, where if you configure it just right, you can trick your circuit breaker into believing that everything is okay when it may not be.

Galen Nelson
Thank you.

Juergen Weiss
That problem exists in Germany. To my knowledge, there has not been an instance where there has been an electrical fire due to one of the millions or perhaps as many as 2 or 3 millions of these systems being plugged in. The official number is a million plus now. You do not know how many people went to Home Depot, and you are supposed to register your system, but we will get into that. No problem. There are safety margins. That is at the origin of why Germany has decided to allow, for now, 800 watts to be injected into a circuit. That is considered safe enough that it does not change the signal the circuit breaker gets too much to create significant risk.

Galen Nelson
Great, thank you. That is helpful. The third issue relates to this notion of exporting power into the grid. Even with a low-capacity plug-and-play solar system, you can imagine that in the shoulder months here in New England, when demand in a building is very low, 800 or 1,000 watts of solar could exceed the load of that building, creating an opportunity for power to be fed onto the grid. We care about the safety of our utility line workers. I want to underscore that there are technology solutions to all these issues. With that, I want to turn it back to you both to react and share your thoughts about these challenges.

Cora Stryker
I want to be careful because we conflated two issues. One is line worker safety. As you mentioned earlier, we have solutions in the inverter itself. All inverters in the United States are UL1741 certified. Within milliseconds of disconnection, whether it is unplugging from the wall or a power outage, it shuts off power immediately. We feel that as long as the inverters are certified in 1741, we do not have to worry about line worker safety in the event of an outage, or touch-safe shock concerns for the household. That is one side. This is confusing because the word back-feeding can mean several things. We feel the line worker safety issue is already taken care of. Other issues, we are still working on. But we conflated that with this idea of how much can you safely back feed to the grid.

Cora Stryker
For context, the way these balcony solar units work is you have your solar panels, you might have a battery on the DC side, but the simplest form is you have your solar panels and an inverter, which converts direct current to alternating current that you can use in your household. Everything you are running off your electricity, your toasters, your heat pump, runs off that power that is injected from the solar panels first. If you go out for lunch and your panels are still producing energy, and you are using very little, it is possible you could have excess energy that you are not using within the household. What happens to that excess energy? It could go into a battery. That is true of many systems here. If you are looking at the simplest system that is the cheapest, that is widely adopted in Germany, you could feed that excess electricity back to the grid. That is your second point.

Galen Nelson
Hmm.

Cora Stryker
What level is safe for that? I am happy to say that we just finished a big project with an expert in the field who was looking at that question specifically, because safety is key to this movement. We cannot have grid instability; we cannot have load predictability issues on the grid. Our expert, Bill Brooks, has written or been on the committee that writes the National Electric Code, NEC. He did an analysis, and in almost every region of the United States, including Massachusetts, we would have no net export, even if we assume something optimistic like a 25% penetration of these 1200-watt systems, meaning 25% of all people in the Northeast have one of these. We have some optimistic projections in our white paper. That exceeds even our projection. Even if we are looking at this huge adoption rate with these 1200-watt systems, which is what we are recommending, you are not going to have any net export to the grid. We go into great technical detail in this report, which we will release soon. We feel that both ends of that safety concern are addressed.

Cora Stryker
There are other safety concerns that, as you framed it, Galen, have to do with adapting the German safety record to our different electrical system. Germany has a 230V system, we have 120V. How do we adapt the German-style systems to ensure we have this pristine safety record? Juergen mentioned, in 10 years of adoption in Germany, there are no significant safety concerns. They raised the wattage limit because of that. Let us not conflate these two issues. We feel that, at minimum, the major safety concerns are addressed if we limit to 1,200 watts now. As soon as we enable this market, technology is going to get much more sophisticated. These developments are in the pipeline. Folks are working on this, but they are not investing as much as they should in R&D because they do not see a large enough total addressable market in the United States. We think legislation should set a limit similar to what Utah just did, 1.2 kilowatts. That will enable the market to come up with technological solutions that are already in development that will allow us to have potentially a higher limit, because we have other technological solutions limiting both backflow to the grid and load within the household.

Galen Nelson
That is helpful. It is such a familiar emerging market dynamic. You have a handful of early movers and early adopters, both on the consumer side and the OEM side, but you are not going to see a significant increase until you have clear market guardrails and boundaries. That is what we need. Innovators will come in with regard to technology, but also business model and finance model innovation to fill the gap.

Galen Nelson
You mentioned NEC. Let us briefly touch on that so folks know how the National Electric Code and UL, Underwriters Laboratories, interact. As consumers, we look for that UL label to make sure we are not going to burn down our homes or injure ourselves. My understanding is that right now, there are UL labels for many of the core components of balcony solar systems, but there is not yet a UL certification for the entire system. Is that accurate? How do these two bodies interact? Why are they both important to the balcony solar movement?

Cora Stryker
Yes, we have component-level certification for all the pieces. I mentioned UL1741 earlier, that has the automatic shutdown. That is a safety measure. This system at the component level is in Utah as we speak, since they passed legislation allowing it. There is a debate, and this is why we need legislation to clarify this, and we need that certification to clarify it, about whether component-level certification is enough. One manufacturer in Utah believes it is. Whether we need a third UL certification for the system end-to-end, UL is working on this third certification. We thought they would have guidance by now, they do not.

Cora Stryker
To address the UL versus NEC thing, currently, there is only one system for these low-wattage plug-in systems that is available in all 50 states. This system is about twice as expensive as the Utah system, because we need an electrician to hardwire an extra piece of hardware to the breaker box to limit that flow of excess electricity to the grid. In that case, NEC is relevant because NEC governs what happens behind the wall, the wiring itself. UL is the gold standard of consumer product certification for safety. If we get what we have in Germany, which is self-installation, a DIY movement, that is how it surged in Germany. If we get that, and we already have it in Utah, we would like to have it in many more states. Then it is a consumer product, an appliance. UL or another nationally recognized testing laboratory would be the appropriate way to evaluate those safety conditions under the worst possible conditions, like older wiring, knob, and tube. We need to do that, but first we need to establish that this is an appliance, a DIY thing. We are not there in 49 of the 50 states.

Galen Nelson
Thank you. We will get to Utah in a second. Juergen, you mentioned the international version of the NEC. Is that relevant? How does that fit into this conversation?

Juergen Weiss
There is something in the IEC, International Electrotechnical Commission, which is a non-binding code. They come up with something similar to the NEC, and countries can adopt it or not. It is important to highlight how this works. In the end, as Cora described, if there is a UL or similar certified product, the NEC should not be particularly relevant. There ought to be clear. That does not mean, because we discussed these issues, you can create scenarios where one of these systems might create a problem in the wiring of the house, which is the domain of the National Electric Code. If you were very one-sidedly interested in avoiding any risk whatsoever of anything ever happening to your house, a very extremist, purist kind of safety standard, you could say, I see a risk. In 10 years in Germany, we have not seen a single incident, but I can construct my toaster example. Therefore, we should, out of safety concerns, prohibit it. That could be a reaction. Interestingly, that is what the current draft of the next version of the IEC does.

Galen Nelson
Which essentially would be like saying to a consumer, you can only buy one toaster. I am exaggerating to make a point.

Juergen Weiss
It does not make sense. It would say, here is an appliance that somebody has deemed safe to plug in, but that is not good enough because we can construct a scenario where that appliance being plugged in, in combination with other things, might create a risk of fire. The NEC is a fire protection code first and foremost. Therefore, we should not allow it. We outlaw toasters. That is a movement. There are vigorous letters being written from various German parties to the standard-setting body saying, you have to be kidding. This has been operating for 10 years without a problem. We have other objectives in our society than preventing a fire that has not happened in 10 years from potentially happening in the future, things like decarbonizing our energy system, making electricity more affordable. You cannot use this backdoor safety concern, which has not empirically shown up at all, to outlaw a revolutionary solution to a problem that we all face.

Juergen Weiss
The helpful lesson here is to assume that everybody buys the story that Cora and I are telling, which we both find compelling, is probably naive. There will be people who do not like this for legitimate reasons, from their narrow perspective, or because it threatens their own business model. As societies, the important goal is to balance various objectives. While the NEC or IEC have a specific angle, we want to make sure people are safe. At the policy level, we have to balance that objective, as we do in many other areas. The safe speed limit on city roads to avoid any accident would be zero. That would be the right speed limit. But we decide it is 30. We always make these tradeoffs. It is important in having conversations with lawmakers and standard-setting bodies that there are other consequences of how you set your standards.

Galen Nelson
That is a great pivot to the Utah legislation. Cora, you have mentioned it a few times. It has gotten some attention in popular media. HB 340 created a new regulatory framework for portable solar systems. It exempts them from interconnection requirements, establishes safety requirements, among other components. The first mover here is Utah. What did Utah get right? Was that bill bipartisan? Do we need to see more bills like HB340 in other states?

Cora Stryker
That is the focus of our organization right now. I think it is lucky that we got our first visionary in Utah, because it firmly establishes this as a non-political or bipartisan movement. We are all looking for something that will unify us.

Galen Nelson
Maybe it is balcony solar.

Cora Stryker
I know I am self-interested in my organization here, but I think it is. We have experienced so much enthusiasm across the political spectrum for this, because it is clean energy, energy affordability, DIY, don\'t tell me what to do in my backyard, enabling markets, slimming down regulation. There is a great deal of excitement about this, in part because in this one little way, we can finally agree.

Cora Stryker
In regard to what happened in Utah, Raymond Ward, a Republican Representative, had this vision. He read an article in the New York Times about a year and a half ago that was talking about Germany, how this is part of the clean energy movement, very empowering, an option for renters who previously had no other options to produce their own clean energy on-site. I want to be careful because the last thing we want to do is position balcony solar in opposition to rooftop solar. We think rooftop is amazing, community solar is amazing, but it is not available to everybody.

Galen Nelson
It is not an either-or, it is a both.

Cora Stryker
Absolutely. Our enthusiasm about balcony has sometimes been interpreted as a denigration of rooftop, and absolutely not. We see ourselves as part of a movement. Politically, we see the enthusiasm around this little issue as the tip of the spear that could get us into a more bipartisan clean energy movement in this country. There are strategic questions about how we do that, but we are working those out internally in legislative offices and among our coalition partners.

Cora Stryker
In terms of Utah, it pushed the envelope. Raymond Ward said, \"I am going to do this." How do I do this? The way they dealt with it, we think, is a great starting place. We might want to make modifications state to state depending on conditions on the ground. Utah\'s legislation is simple. The meat of it is half a page long. You summarized it beautifully. It says the typical interconnection rules designed for rooftop solar just do not apply to these little systems. In order for them to not apply, we have to set a ceiling for how big they can be. That is basically what that piece of legislation does. We think that is the right place to start with simplicity. Technological innovations we know are in the pipeline may change this picture in terms of how much we can generate. In the Utah legislation, the way it was interpreted, they have this 1.2 kilowatt ceiling. The language\'s \"output\" can be interpreted in a couple of ways. Are we talking about inverter output to the household, or inverter output to the grid? There are technologies in development right now called power control systems. They could change this picture because they could ensure circuit safety within the household at larger generations and control how much is exported to the grid. We believe we have to write this legislation generally enough, like Utah HB 340, to enable the market to develop these solutions, because they are not investing in us yet. They do not see enough places where this could be deployed in the near term. Legislation will change that.

Galen Nelson
More about setting broad boundaries and remaining technology agnostic to enable.

Cora Stryker
Yes, while ensuring safety with certifications like UL and NEC. That is important. In the meantime, while this technology is developing, we have to make sure people are safe. We feel Utah did that with the UL certification requirement and the NEC requirement. That is our blueprint as we move state to state.

Galen Nelson
That is great. Juergen?

Juergen Weiss
I totally agree. It should be accessible in all 50 states based on some reasonable set of standards. Utah seems like a good start. Germany, France, other places allow this now. Where I disagree a little bit, and Cora already hinted at it, is that this is all of the above. It is not going to touch on rooftop solar or community solar. For me, what is exciting about this is the fact that this is an appliance. The way we install renewable energy in the desert of Nevada or on a rooftop is not appliances, they are projects. Projects are more expensive than appliances everywhere in the world, particularly more expensive in the United States. A rooftop solar installed in Germany averages a little bit more than a dollar a watt. It is 80 cents a watt in Australia. Where we live, it is more like \$4 a watt.

Cora Stryker
\$3 nationally on average.

Juergen Weiss
Nationally, 3, but Massachusetts is amongst the most expensive. Why is rooftop solar three or four times as expensive in the United States as it is elsewhere? That is a separate discussion. If you look at Lawrence Berkeley National Labs\' reports on solar over the last 20 years, the costs of an installed solar system, the technical components, the panel and the inverter, have basically disappeared from the cost stack. They are little lines at the bottom. The rest is red tape, installation labor, and customer acquisition. One of the reasons balcony solar is so attractive is it cuts out this piece.

Cora Stryker
That is fair.

Juergen Weiss
It also might function. I would be surprised if some of the larger rooftop solar installers were not threatened.

Cora Stryker
Yeah.

Juergen Weiss
That is good, because it encourages cutting costs in an area where there have been substantial subsidies that have allowed that industry not to push costs down so that consumers get access to these systems at prices comparable to the most advanced places in the world for rooftop solar. I think there is a bit of a conflict.

Cora Stryker
I do not see a conflict at all.

Juergen Weiss
It is a conflict in that it will be disruptive to the solar rooftop installation space. We are talking about tiny systems. They are smaller than a typical rooftop solar system. Let us take the average between Germany and Utah and call it 1,000 watts as the injection limit. If the sun was shining 8,760 hours a year, you could inject 8,760 kilowatt hours into your home with a balcony solar system. That is not very different from the typical average household electricity consumption, probably without heat pumps and an electric car. That is not a tiny amount anymore. The trend in Germany and elsewhere is that when you buy a balcony solar system, you buy it with a battery. The battery will allow you to deploy 150 panels in your backyard and have a gigantic battery, and inject 1,000 watts every hour. That is an unrealistic scenario, but over time, with more technological progress, the share of your electricity consumption you might be able to offset with plug-in systems may increase beyond what we envision today. Other players in the system might feel more pressure than they do today.

Cora Stryker
I love what you are saying. You are right; soft costs, the cost of marketing, installation, labor, are 40-60% nationally. Where I live in the Bay Area, it is around 60-65% of the total cost of a rooftop system. I love how you frame that this could spur innovation in the rooftop solar world as well. I think disruptive is the correct word there. We want allies everywhere. We might not be able to form allyships everywhere, including with the rooftop solar industry. We are a nonprofit. We care about clean energy; we care about energy affordability. We want to get to that vision where we are on par with Australia, on par with Germany in terms of how much it costs per watt to install these rooftop systems. I love that idea. This could be a kick in the pants for the rooftop solar industry to get its act together and take seriously this dysfunction of soft costs distorting the market value of rooftop solar far beyond the dirt-cheap cost of PV modules and inverters themselves.

Galen Nelson
Disruptive technologies in other sectors within.

Cora Stryker
It is.

Galen Nelson
We should not be allergic to disruptive approaches in a well-established market. Thank you.

Cora Stryker
This could be a great moment for that, because with the loss of subsidies with the IRA, the rooftop solar industry is looking for solutions to remake themselves. This might be the moment to have a spearhead into that established paradigm of high soft costs.

Galen Nelson
Let us talk about, because we do not have an enormous amount of time left, and I want to make sure we get to some questions. Let us talk about who the market actors are. You mentioned one, Cora. Is that Kraftstrom that you were referring to, the system that requires an electrician? Or is that another OEM?

Cora Stryker
I would rather not mention any companies by name. We are a nonprofit here for clean energy and energy equity. I will say that at this moment, we are at a very immature market. We have two players here, with different configurations, different theories of why their system is permissible even in this regulatory gray area. We think they are both a part of the puzzle of how we get to this ultimate goal of everyone having access to DIY, affordable, clean energy. All the manufacturers that are currently invested in Europe want to come here. They tell us, this is in our white paper at BrightSaver.org, that they need to see about five small states, one or two big states, and then they will come in here. They want to.

Galen Nelson
The early policy movers have a real opportunity. The states that move quickly to create a clear and accessible market for balcony solar may be better positioned to attract those OEMs.

Cora Stryker
Absolutely. That is what we want. That is our theory of change as a nonprofit.

Galen Nelson
I think one of you mentioned renters. I want to touch on that. We have a lot of rental units in Massachusetts. There is the landlord-tenant split incentive challenge. There may be other challenges to renters deploying solar and other clean energy solutions. You hear about renters buying their own induction cooktops. Renter interest in balcony solar could take off. Should we see balcony solar on every south-facing triple-decker in New Bedford and Worcester and so on? Will balcony solar drive sound systems at future Porch Fests?

Juergen Weiss
Yes, we hope so.

Cora Stryker
Renters have very few options. That is our goal, our dream. We want to walk through New Bedford and have it look like Munich, see all the south-facing PV units that previously could not exist before we cleared the way with this regulatory reform.

Juergen Weiss
The south-facing stuff, you want to face the right direction. But going back to the Lawrence Berkeley National Lab thing, the wholesale cost of a panel is 8 cents a watt, maybe 10 cents a watt. That is one-fortieth of the installed cost of a rooftop solar system in Massachusetts. The inverter is a little more expensive per watt, but the fact that you place your panel in a position that is not optimal towards the sun is less relevant. In Germany, they built fences with solar panels. Having more of this in consumers\' homes as appliances is desirable. Cora alluded to it earlier, it is the entry point. When people install these things, they look at their inverter app to see the shape. That access you get with your balcony solar system will get people hooked and more informed about energy in their homes, energy production. It becomes a step towards doing other things in your home.

Juergen Weiss
Another big benefit of this, true on the cost side and on the timing side, is you do not need any of the skilled labor that is in super short supply. In Massachusetts, if you are finding a plumber, it is like winning the lottery. The same is true for electricians. The more we can develop appliances, plug-in appliances that substitute for these things being projects, the better. You mentioned the induction cooktop for a renter. At IKEA, you can buy a plug-in induction oven now. That is the right direction. There is one heat pump, the window unit heat pump that you just plug in. They are not cheap, they are pretty expensive, but you are saving thousands of dollars in installation labor.

Galen Nelson
They are portable, so you could take them with you when you move.

Juergen Weiss
On the renter thing, a critical piece of the legislation in Germany was to prohibit landlords from objecting to renters installing these units. That is an important thing to create, because there will be attempts by homeowners associations and landlords to exclude these things.

Galen Nelson
An important opportunity for municipal climate leaders to keep their eye on that, to make sure there are not unnecessary municipal roadblocks.

Galen Nelson
A practical question on cost. I know it varies. Cora, I respect your desire not to mention particular manufacturers, but can you ballpark what these systems cost here? What will they cost? What is the ROI? I am sure the ROI depends on your electricity costs, but a ballpark would be great for our listeners.

Cora Stryker
This is all detailed in our white paper. The simple system in Utah only is around \$1,000 for an 800-watt system, which is almost German levels. Not quite, Germany still is better. In terms of ROI, currently, even in this restrictive regulatory framework, about four or five years, depending on where you are, how much an electrician costs, and your energy prices. For the workaround system, more expensive, almost double when you consider the cost of the electrician. We see that as a step in the right direction, but we have to go further. Only legislation or direct regulatory reform can get us to the place where we can all get the Utah system. The Utah system does not go far enough. When we get all these manufacturers into the game who want to come, they will compete against each other, and prices will fall even further, quickly.

Juergen Weiss
In Germany, they have Black Friday, too. I get deals advertised for about 300 euros for an 800-watt system. It is still two and a half times more expensive in Utah, but it is understandable. There is zero scale. Utah has a small population and a very small market. In Germany, there are lots and lots of suppliers. It could go down to something like 30 cents a watt.

Cora Stryker
Yes.

Juergen Weiss
Which is 90% less than Massachusetts rooftop solar. You have a lot of room for not orienting your panel in the right direction and still have much quicker payback periods.

Cora Stryker
Agreed. If you want to check out our white paper, we go into that.

Galen Nelson
To be clear, you could do both. You could have a rooftop system, whether you are an owner or a renter, and have a plug-in system as well.

Cora Stryker
That is happening in California. We are not a manufacturer, but we are doing an expansion for folks who already have rooftop, and this is a fully legal thing because it falls under the interconnection agreement they already have. People are doing both. A lot of folks have maxed out their roof space. I cannot get more; it is too shady, but I could have one of these backyard systems on my patio. More is more in this case.

Galen Nelson
Great. Let us turn to a few questions from the audience. One, and I think we touched on this, but it would be great to hear one or both of you confirm. Someone asks about balcony solar providing energy resilience during power outages. I think you need to add a battery. Is that correct?

Cora Stryker
Yes, that is correct.

Juergen Weiss
It is a little more complicated. We should work towards finding solutions for that. Right now, if there is an outage and the grid is down, your microinverter will shut off injection. You cannot use the power you have plugged in to power anything at home. If you have a battery on the side, you can do it. If you literally island your house, your house becomes your electric system. You have batteries and solar panels plugged into your local circuit, and it works. You do not have to unplug your refrigerator. That provides resiliency benefit for an outage. With balcony solar systems by themselves, and especially with batteries, from the grid perspective down the road, they could provide tremendous benefits because it is just distributed storage and renewable production, like your rooftop solar system, which is just beginning to be featured as part of the virtual power plant mix that the grid can use.

Cora Stryker
Absolutely.

Galen Nelson
Someone asked about safety concerns related to installing these systems on balconies or railings that may be structurally problematic. With any appliance, you have safety recommendations and standards. Perhaps one or both of you could speak to that concern.

Cora Stryker
Juergen, if you know what is happening in Germany with respect to that, I would love to hear.

Juergen Weiss
I would put this in the category of, you can always create a problem for yourself. If your balcony is structurally unstable, maybe you should fix it. Intervene at the balcony level. The products have to follow some standard. A lot of the simple systems are flexible solar panels. They have a couple of holes on each corner, and you use zip ties. They weigh a couple of pounds. You are not going to overload your balcony by adding a few pounds. I do not think this is an issue. If you are worried, there are products out there that might mitigate that risk.

Galen Nelson
This is a fun question. I believe it is from someone at one of our MLPs. Can you move them seasonally? It is making me think of tune glazing in high-performance buildings. We are moving to a winter peaking system. You said it does not need to be perfectly south-facing. Maybe we should have more balcony solar facing due east on cold winter mornings, injecting power when we need it most, when people are warming their homes with heat pumps. Maybe they should be west-facing during the summer. If you could easily move them around, that is why we have tracking systems for ground-mounted solar. It could be a fun project for the kids, time to move the solar.

Cora Stryker
Absolutely. Depending on the configuration. If we are zip-tying into a balcony, we have this horizontal orientation. Most are bifacial, so that is good. With backyard systems, you can change the angle, move it around. That feeds into what Juergen was talking about, energy awareness. How much are you going to generate depending on this orientation, this season? How much are we using? We love that because the more energy-aware folks are, the more self-policing, curtailing of energy usage we will get. A lot of folks, before they got rooftop solar, did not understand what they were doing that was most wasteful from an energy perspective.

Galen Nelson
This has been great. I know we are out of time. Several folks, Cora, have asked if you could drop the link to your white paper in the chat. You have mentioned it a few times.

Cora Stryker
I know, I am sorry. Believe it or not, I have a webinar right after this on the white paper. That is why I keep mentioning it.

Galen Nelson
I want to thank you both. This has been a fun and fascinating conversation. I enjoyed it. I want to acknowledge my wonderful colleague, Shayla Brown-Petty, who helps produce Thoughtful Climate. If you do not want to miss future episodes, you can sign up at masscec.com/subscribe. You will learn about what we will be discussing in 2026. Thank you both for joining me today. Thanks to everyone who tuned in. It was a fun conversation. Look forward to seeing you all next time.

Juergen Weiss
Thank you, Galen. Thanks, Cora.

Cora Stryker
And here is that. Thank you, this was super fun.

Galen Nelson
Thank you both.

Cora Stryker
Okay.

Galen Nelson
Take care.

Cora Stryker
Bye.

Juergen Weiss
Bye.

Galen Nelson
Bye-bye.