If you count yourself among the people who love the idea of making their own clean energy, but balk at the idea of planting a pole mount in the middle of your backyard or covering your historic home’s rooftop with high-tech PV modules, this fresh design strategy offers a solution.
The concept—aptly dubbed “solarscaping”—is a new take on building integrated photovoltaic (BIPV) systems. Unlike traditional BIPV systems that are designed into a structure from the blueprint phase, solarscapes work with both new and existing structures and can minimize the aesthetic concerns of adding PV to your home.
“Solarscaping is another avenue to facilitate our mission of helping people choose solar power,” says Scott Franklin, president of Lighthousesolar, a solar system design and installation company based in Boulder, Colorado. “The more options we can provide our customers, the greater chance we can meet their needs. These designs allow customers to get more function from their PV investment.”
Though the idea of integrating PV into architectural structures is not new, Lighthousesolar is one of the first to offer a package option that also can be custom-fit to an application. Installation of a solarscape involves minimal time at the site. Structures are customized in the company’s workshop in Boulder, delivered to the installation site in several large pieces, and assembled in one or two days. So far, the company has integrated PV systems into awnings, pergolas, carports, hot tub shades, and gazebos, and the potential is limitless, Franklin says. Fences, fountains, greenhouses, archways, and sunrooms are all good candidates, he adds.
A solarscape features two elements. The first is a wooden or steel custom-made frame that is painted, trimmed, or finished to complement the home and landscaping.
The second component—the HIT (heterojunction with intrinsic thin layer) bifacial modules made by Sanyo—is key to the design’s sleek look and increased energy production. These double-sided modules—which harvest solar energy from both the front and back faces—maximize power within a fixed amount of space. In an ideal setting, bifacial panels can be the most cost-effective modules based on dollars per watt.
Instead of the standard opaque module backsheet, Sanyo Double modules have glass-on-glass construction. Clear glass layers on both sides of the photovoltaic cells allow additional reflected solar energy to be captured from the back side of the module. The glass-on-glass construction adds aesthetic value as well by allowing some light to filter through the array. The subtle octagonal design of the silicon cells projects a soft light-and-shadow pattern on the surfaces beneath the array—similar to light filtering through the leaves of a large-leafed tree. Enough light passes through the modules to allow plants to grow underneath the array canopy while providing adequate protection for those seeking respite from the sun.
Unlike monofacial (single-sided) PV modules, the back side of a bifacial module generates power from light that is reflected off surrounding surfaces. Radiation from reflective surfaces—light-colored wood, metal roofing, concrete, white gravel, snow, or water—can increase the energy yield beyond the manufacturer’s standard test conditions (STC) output ratings. Sanyo estimates that the bifacial construction adds approximately 10% to module output when compared to a single-sided Sanyo HIT module in an angled installation, or as much as 34% in a vertically oriented installation.
“We know the bifacial panels have a strong power advantage, but it’s hard to quantify because each installation has different characteristics,” Franklin says. “Even Sanyo is hesitant to predict output because the numbers can vary significantly based on installation specifics.”
Based on reports he has received from the field, Benjamin Collinwood, Sanyo’s solar market development manager, estimates that typical production increases will be between 15% and 20%. He says that system results vary, depending upon individual site characteristics such as system design, location, and site albedo.
Beyond the reflective radiation advantage, solarscapes can offer a much-needed solution for properties without a shade-free location for a roof- or ground-mounted array. Likewise, many buildings have less-than-optimal orientations for solar energy collection. Solarscaping can provide new and attractive options for array siting in many locations.
Homeowner Neil Cannon wanted to integrate PV into his newly built house in Eldorado Springs, Colorado, but he did not want to compromise the home’s historic-looking design. Because tall trees shaded areas closer to the house, he needed a freestanding unit that could be located more than 100 feet away. Adding to the challenge, the structure had to be tall enough to avoid the shade of nearby trees.
The solution? A customized double carport roofed with 4.5 kilowatts (KW) of PV modules to meet 100% of the household’s electricity needs, and several evacuated tube collectors for solar water heating. To keep with the look and feel of the home, the sides of the structure will be finished with rough-sawn lumber that resembles old barn siding.
“We’re really charged about the idea,” Cannon says. “It was really important that the structure be congruous with the landscape and the home, and this is a great compromise. Up close you’ll be able to see the high-tech gear, but from far off in the distance, it’ll blend in nicely. ”
Solarscapes offer several access and maintenance advantages over typical roof-mounted PV systems. The absence of roof-mounted arrays, for example, means roof maintenance and remodeling can be done without dismantling the solar-electric infrastructure. Increased airflow around the array will keep module operating temperatures lower and result in increased energy harvest.
A prototype of Lighthousesolar’s signature Power Awning at Franklin’s home has won over several homeowners (see Functional Design sidebar). All it took was one look at the awning’s sleek design—a black steel frame inset with double-sided PV modules—to sell Marcus Luscher on the concept.
“When you first look at the awning, you don’t even notice that it’s a PV system. Only when you actually sit beneath it and see the PV panels do you realize that the awning is also generating power,” Luscher says. “It’s an attractive piece of architecture that is multifunctional.” He plans to add a power awning above the deck at his home in Nederland, Colorado. The solarscape system will supplement his current nine-module PV system and help offset the electricity consumption of his newly purchased hot tub.
While bifacial PV awnings and carports are common in commercial BIPV installations, the concept is relatively new to residential projects. But solarscaping is gaining traction in home-scale installations because of potential aesthetic and versatility advantages when compared to traditional roof- or ground-mounted arrays.
Currently, Lighthousesolar delivers and installs customized units in Colorado and Texas, but the company has plans to expand its installation territory. Lumos offers prefabricated solarscape kits to building contractors nationwide.
Several module manufacturers have partially transparent glass-on-glass modules that will soon be headed toward the U.S. building market. In the years ahead, these PV modules will undoubtedly be used in both prefab and custom residential structures, creating spaces that are as productive as they are attractive.
Topher Donahue was born in a cabin without running water in Wild Basin, near Colorado’s Rocky Mountain National Park. He is now helping his mother upgrade the cabin to photovoltaic power. His business, Alpinecreative (www.alpinecreative.com), based in Nederland, Colorado, provides photography and writing for the outdoor recreation and alternative energy industries.
Lighthousesolar • 303-638-4562 • www.lighthousesolar.us • Power Awning installer
Lumos • 303-449-2394 • www.lumossolar.com • Power Awning, double carport, and hot-tub shade manufacturer
Sanyo Solar • www.us.sanyo.com • Bifacial PV modules