Ask an Expert: The Future of Solar with Building-Integrated PV

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Intro

The future of solar isn’t flat black panels. Thanks to the development of a technology known as “building-integrated photovoltaics,” solar cells are now placed in all different locations—in windows, in roof tiles, on the sides of buildings, in glass atriums. The idea is to design the cells so that they fit seamlessly into a building’s architecture, rather than tacking on solar panels to roofs as an afterthought.

Romag, a solar manufacturer and installer based just south of Newcastle in England, specializes in these kinds of designs. In fact, they even designed the panels on the well-known Kingsgate House in London, a refurbished concrete site that they finished with luminous gold-speckled cells. Today we sat down with Romag’s Sales Manager for the Solar Division, Mick Robinson, who enlightened us on what’s new in the solar market and where solar panels are headed.

We’ve seen a lot of building-integrated solar systems for commercial sites, but not too much yet for private homes. How do you think that technology will play into in the future of residential solar?

I think that is the future—at least that’s what we’re seeing here in the UK market. A lot of the major house-building is run by a dozen or so house builders across the UK, since we’re a bit smaller geographically. They build across the whole of the UK, and a number of these properties want to integrate solar within the rooms rather than the systems that sit on roofs.

Do you think that integrated systems will have more aesthetic value?

Absolutely. There’s a number of different factors for that. It looks so much better when the housebuilders are building new properties. But then you get into competition between the different housebuilders, too. A lot of these people are building sites that contain 20 or 30 houses almost right next-door to each other—and if you if you try to build a home that’s a half mile or a quarter mile from a house that has a roof-integrated system, it just makes it more desireable to add one to the new home, as well. It’s almost a little bit of peer pressure, in that respect.

One of the big drivers in the UK is that certain local authorities require new buildings—even homes—to have a percentage of energy based in renewables. What the homebuilders are finding is that the most cost-effective way of doing that is to go solar. And while up-front cost is an implication for a homebuilder, there’s another factor that’s even more important—the fact that a solar PV system is basically just plug-and-play. No one has to be educated on how to run the solar panel, because it just works. With other renewable energies like heat pumps, you have to educate the homeowner how to run it to make sure it’s kept up and running smoothly.

Solar Windows at Nijmegen University

With glass walls and building integrated systems, does insulation ever become a problem? How do you make sure the building stays comfortable and energy-efficient?

That tends to be more of an issue with commercial buildings. When designing a standard house in the UK, there’s two ways that we can do it. One would be the traditional brick-and-block, where we just install a roof and some windows. The architect usually has to create some sort of design that meets building regulations with regards to heat loss. And he’s probably already done that calculation long before they decide what kind of renewables they need to incorporate. It’s a major part of the government’s building regulations. Anything in regards to glazing actually falls into that.

When we’re installing glass-on-glass photovoltaics, we’ll fit them into windows and atriums and that kind of thing, even at that point, there’s a requirement of what type of glass would be needed. All we’re simply doing is mirroring that glass type

and that kind of thing, even at that point, there’s a requirement of what type of glass would be needed. All we’re simply doing is mirroring that glass type build up, and putting PV cells in there. So what you’re getting is basically a double-glazed unit that’s already been calculated to meet building regulations in regards to heat loss, but you’re also getting a source of PV and some solar shading when it’s required. It’s a great system.

We don’t get a lot of requirements when it comes to that kind of PV for residential units. When it comes to high-end, specialized designed buildings, it certainly tends to be much more in regards to commercial buildings.

Let’s talk about pricing. Do these units cost homeowners a lot?

The basic modules that we see all across the world by any company that manufactures PV panels are pretty much manufactured to the same size, with a similar output. But in the UK manufacturers, we—unfortunately—can’t compete with the price of Chinese imports.

So we try to create differences, and one of those is with the roof-integrated system, which is very particular to the UK market. In a way, we’re tile and slate layers. There’s a lot of areas where we can provide solar PV within glazing systems and actually enhance the look of the building at the same time.

The UK isn’t known for its sunshine. How do you maximize the output with your systems to take advantage of all the sunlight you do get?

When we look at the UK, it’s always ideal that we have it as south-facing as possible, and at a pitch of 35 to 45 degrees, since this will result in the best output. England is effectively a long, skinny country, so the higher north you go, you do see a definite drop in the expected output. But unfortunately, that’s one of those things: we can’t change where we are.

What about windows versus roofs? Are there significant differences in these different techniques?

Yes, absolutely. There’s a slight difference. The pitch of a normal roof is typically between 30 and 45 degrees. But with a window, you’re now looking at a 90-degree pitch, since it’s vertical. And that affects the amount of sunlight that will capture.

If BIPV takes off, do you think that it could influence architecture—for instance, that walls would be designed to maximize solar output?

Possibly, in the long-term. It may affect the way an architect thinks when he considers how the building is going to look. Because I’ve spent a little bit of time speaking to architects—particularly in London, where the big architects are—it does seem to be a common concensus that architects will design with solar in mind.

But what we’re doing at the moment is designing the building and then fitting the solar elements to suit. The time may come when architects will start to look at it—probably when they’re pushed to create higher energy and then get to the limit of how much they can get based on current designs. Then you actually have to start considering how that building looks to create the glazing space to be a little bit more efficient.

Today, there are so many buildings that could utilize some sort of vertical glazing with a solar PV element to it. That will increase its efficiency and its appearance since it’s more visually appealing.

Solar BIPV at Alliander Group Site

Beyond incentives, what sort of benefits do homeowners get when they integrate solar into their homes?

It really depends on how you live your life. Let’s compare two identical homes next door to each other. If one is home to a family of five—three kids that are at school all day and two parents that are at work all day—they’re not really utilizing a lot of their solar energy, because they’re gone most of the day. But let’s say that next door is a retired couple who are home all day. They’re using their energy, so they’re going to be much quicker to replenish the cost of the system.

When we look at the future, we know that energy isn’t going to get any cheaper—it’s just just going to continue to rise. So that window where you’re paying back the cost of the system—and you generally always will be paying it back—is never going to get longer.

In the UK, it’s generally takes about eight years for the average-sized system to pay for itself with the energy you’re going to be making. You can guarantee that it’s never going to be any longer than eight years, because the energy’s going to start getting more expensive. So it could drop from eight to possibly six years.

The cost of solar has actually gotten more affordable as well, and the panels and systems that each manufacturer develops are becoming more and more efficient as the solar cells become more efficient. That means that every argument for buying a solar system for any building today will increase in the next five to ten years because cost will have decreased and efficiency will have increased—and therefore, your energy will be much more valuable.

I’ve heard that you put gold-colored cells on a building in London. Do you do other colored cells as well?

Because we do building-integrated PV, we can integrate different colored cells into the glazing. I’m actually speaking to an architect at the moment who’s looking at two properties, one with a black-colored cell, and one with a green, almost an emerald-colored cell.

It’s not just about putting solar PV on the building. There’s so many ways we can enhance it, because we can play around with the panels that we produce. We have to manufacture it as a glass laminate, so we sandwich the solar cells between two panes of glass. We can make them so that they’re single pane, just a single pane of glass, or we can make it into a double-glazed or even a triple-glazed system. On the panes of glass, we can screen print it with different colors, we can even put on screenprinted writing. We can almost even make it an art piece.

Do you do things with the shape and design of the glass as well?

It’s possible. We’re working on one at the moment where we’ve got some triangular panels on a frame. Strangely enough, this is for a bike shed—about 50 yards long—outside of an apartment building. It’s being built next door to the Olympic Stadium, which is where the 2012 Olympics were held. There’s a lot going on over there, so they wanted to have a nicely-designed solar-powered bike shed. We’re working on triangular panels, we’re now speaking to someone who wants oval-shaped panels, so there’s a number of different things we can do.

Certainly the vast majority of panels produced are square or rectangular and they’ll fit into a frame. That’s fine. But there’s so much more you can do. In fact, we’ve actually done what’s called a “solar tree.” It’s basically a bunch of metal poles designed to make a tree, and the leaf shape is actually solar panels. That was for a project we did in the Netherlands.

We’re only scratching the surface of what we can do with this type of system, so there’s so much more we can do when we start getting more and more architects into this to make it more of a design, and not just a utilitarian piece of equipment.

That’s so exciting to hear! We’re definitely looking forward to a more beautiful, solar-powered future. Thank you for talking with us today, Mick!

Thanks for having me!