The best way to bring down the installed cost of a solar system is to reduce both the balance of system and labor. A new module attacks both areas with an adhesive, non-penetrating, non-racking system that can be quickly installed by just one person.
Publicity around Lumeta’s adhesive, light-weight crystalline silicon solar panel has come in spurts over the last eight years, so you’ll be forgiven if you haven’t heard of the game-changing product. Seen exhibiting at Solar Power International in 2010, Lumeta went back to the drawing board and used its involvement in a SunShot Initiative-funded program to now launch both residential and commercial products in 2017.
We’re sure solar installers have many questions about Lumeta’s LPP modules—Adhesive? No penetrations? No racking? What?
We chatted with Lumeta CEO Timothy Davey to learn more.
What’s Lumeta’s history?
Davey and the rest of Lumeta’s founders have nearly 30 years’ experience in the commercial roofing business, installing roofing systems through DRI Companies. In 2007, DRI customers approached the team for suggestions on solar systems appropriate for commercial rooftops.
“Our customers, especially the big box retailers, began asking us to help them identify solar systems that didn’t have an adverse impact on the additional load increases caused by traditional rack-mounted systems, as well as the numerous penetrations required to install rack-mounted solar systems,” Davey said.
Rather than give business to other suppliers, DRI invented the non-penetrating, peel-and-stick Lumeta module.
January 2011 saw the first commercial installation of Lumeta’s PowerPly solar panels on the roof of the Musical Instrument Museum in Phoenix. The museum’s president touted Lumeta’s “no-compromise” efforts to the roof’s integrity. The panels, first marketed as a BIPV option, had a 400-W peak power rating and 13.8% efficiency. Using DuPont Tefzel front sheets instead of glass, Lumeta panels also eliminated the need for aluminum frames. Back then, they weren’t super light-weight (65 lbs on its 2010 spec sheets), but the lack of 2010 racking supplies definitely contributed to an overall lighter system.
What’s the story behind the new generation modules?
The second generation Lumeta modules (LPP-175S and LPP-185T) will launch in Q1 2017. They’ve changed a lot from their initial design—and they’re backed by some solid research.
LPP-175S, intended for application over asphalt shingle roofs, was developed in conjunction with the Fraunhofer Center for Sustainable Energy Systems (CSE) through the Plug and Play PV for American Homes program. The program’s objective is to complete a plug-and-play PV system that can be installed in 10 or fewer man-hours by someone without prior solar experience and meets the SunShot goal of $1.50/watt installed cost for the residential market by 2020. The complementary LPP-185T module is suited for concrete tile roofs.
Fraunhofer CSE successfully completed its first full-scale installation of its Plug and Play PV system (with Lumeta modules) in November 2014, and Lumeta received UL 1703 certification on both LPP module lines in late 2015.
What’s the technical data?
The two module lines are basically identical except in a few small areas, but from here forward we’ll discuss the shingle module (LPP-175S).
The Lumeta panel weight has dropped to around 17.5 lbs, and it’s only 3 mm thick (a traditional glassed panel is about 35 mm thick). Forty monocrystalline silicon cells encompass the square-like module shape.
Davey said the company went with silicon instead of a more BIPV-friendly thin-film material to “take advantage of c-Si’s proven long term output performance as well as its high conversion efficiency.”
Lumeta modules (175 W for the shingle module, 185 W for the tile module) adhere to the roof with a thermoplastic butyl adhesive that has been wind tested to 120 mph. This time-proven adhesive (branded Royal/ADCO) can be removed by heating the module with a commercial utility blanket (to ~175° F), with no damage to the roof. If the module would then need to be reinstalled, adhesive would have to be reapplied. Instead of glass, the topside of the module is again sealed with a DuPont Tefzel front sheet with a tapered edge to prevent soiling and water ponding.
The junction box is housed on top of the panel (it’s on the backside for the tile roof panel), and a tray is pre-installed on the top edge to cover and manage wires (underneath on a tile roof). With no penetrations or need for row spacing, the Lumeta modules can connect together for a seamless, monolithic array. To ensure ideal adhesion on tile roofs, shaped inserts/wedges are adhesively applied to the roof to create a flat surface for the full module to attach.
Davey said microinverters can be used with the Lumeta modules, which will prove to be easier if/when microinverter sizes get smaller. The company is considering offering modules with DC optimizers to accomplish module-level shutdown, installed in place of the junction box.
What’s the catch?
It’s difficult to compare the Lumeta module to either BIPV products or traditional, rigid crystalline. They sort of fall into a brand new category.
“[Lumeta is] comparable if not superior in its electrical production (to glass c-Si panels) but much lighter, non-penetrating and more aesthetically pleasing,” Davey said. “More importantly is our ability to provide a module with a price point that will result in the lowest installed system cost on the market for rooftop installations, given the offset of BOS and labor costs.”
Installers are able to complete five times the number of residential installations in the same timeframe and with the same work force as a standard rack-mounted system on an asphalt shingle roof, Lumeta claims. Tile roofs can see a 15-times installation improvement.
The residential modules are a modest 175-185 W, with a commercial model expected to hit 320 W. Davey said the company is going through testing right now and expects next generation modules to have a higher wattage—predicting 270-280 W for the shingle and tile panels. As output gets more competitive, the modules can make more sense in all situations.
Installation is faster and less labor intensive than traditional racked systems, that’s obvious. A Lumeta system is ideal for consumers concerned about aesthetics, roof penetrations and/or roof load. If someone is looking for maximum output, Lumeta isn’t 100% there yet, but the cost savings are difficult to ignore.