2011-08-15 | Editor : D.A. Barber 6004 pageviews
PV Roof Shingles
Solar roofing shingle and tiles blend traditional roof building techniques, PV advances and water proofing technology to essentially create a functional roof that generates electricity. But unlike big, bulky glass and metal PV panels mounted on existing roofs, solar shingles and roof tiles are seamlessly integrated into the traditional roofing style of materials.
The mix of these various disciplines result in a practical application that is the latest trend in the building-integrated photovoltaics (BIPV)market. But this marriage between the PV industry and the roofing industry is not new. In 2009, Time magazine named solar shingles as one of the top 50 inventions of the year. But that part of the BIPV market is just now taking off and the development of solar shingles and tileshave seen some recent global BIPV industry movement, particularly with recent advances in thin-film and CIGS (copper-indium-gallium-selenide) PVs.
PV Tiles and Shingles
Solar shingles utilize the same PV technology as bulky solar panels but with considerable less power output. A single PV shingle only produces between 50 and 200 watts, but several square feet of BIPV shingles together can power an entire house. Some roofing manufactures that have not been traditionally part of the PV supply chain, such as Dow Chemical, Redland and EternaTile, have recently entered the BIPV market and have designed their products to blend and be installed just like a roof shingle - hand or gun-nailed - with one simple connection to link shingle to shingle and row to row of the entire solar array to the home electrical system. These systems are designed so that if any individual solar shingle or tile fails, the entire system continues to operate.
Part of the BIPV Market
The latest generation of solar shingles is not only beginning to emerge in the marketplace after years of R&D and prototype projects, they are also factoring into the growth of the BIPV global market. Most of these BIPV opportunities are materializing in those European countries which are still offering lucrative feed-in tariffs for BIPV, while markets in North America and Asia are developing quickly.
A July 2011 report form NanoMarkets estimates that revenues in the entire BIPV product market will surpass $11 billion by 2016. The report, "Building Integrated Photovoltaics Markets, 2011," also estimates that global BIPV capacity will rise from 343 MW to 3.6 GW during the same time frame. According to the report, the revenue growth of the next generation BIPV products will include a rise from $691 million to $3 billion for the “tiles and floating panels” sector and an increase from $153 million to $1.9 billion for the “flexible products” sector.
Next Generation Product Trends
A variety of companies in the BIPV supply chain have stepped-up development and manufacturing of solar shingles and tiles. Some of the more recent developments include:
Michigan-based Uni-Solar has been evolving its PV shingles to make them more aesthetically pleasing. The company will begin producing its PowerShingle during the fourth quarter of 2011. PowerShingle is meant to mirror traditional asphalt shingles, the most common residential roofing material used in the U.S. PowerShingle has a smoother surface than the traditional asphalt shingles but maintains many of the other characteristics of asphalt shingles, such as thier size, shape, weight, flexibility, thickness and weather resistance. And they are installed using the same materials and techniques as asphalt shingles.
Arizona-based Global Solar Energy’s main focus is its flexible thin-film CIGS embedded solar shingles done in partnership with Dow Chemical Company. Global Solar’s PowerFLEX roofing module recently received the International Electrotechnical Commission certifications, as well as the Underwriters Laboratories 1703 certification. According to company statements, the module has a large format (5.75m x 0.5m) and a power output of 300 W, enabling it to “outperform other flexible solar roofing shingles on the market, including generating 50 percent more energy and power than the current amorphous silicon standard.” Global Solar’s state-of-the-art facilities in Tucson, Arizona and Berlin manufacture the PowerFLEX PV shingles and the company is currently looking for another manufacturing site to ramp up production.
Dow Chemical Co.’s Powerhouse Solar Shingle was developed in 2009 after the company received a $20 million grant from the U.S. Department of Energy to develop the shingles, which are designed to be installed on roofs with standard asphalt roofing materials. Dow’s solar shingles use the CIGS modules made by Global Solar, wrapped in a proprietary Dow plastic. They will be available in targeted U.S. markets by the end of 2011. Dow also announced in June 2011 it was building a new, large-scale manufacturing facility at the company’s Michigan operations site, which is expected to begin production in late 2012. The plant represents the first phase in a production ramp-up to 220 MW of annual solar shingle capacity by 2015.
Germany-based Solarwatt has launched their new Solarwatt Easy-In roof solar tile system, which is been specifically designed for replacing conventional roofing tiles on pitched roofs. The upper module frame is screwed directly to the roof battens while the “easy-in” modules are pushed together with a tongue-and-groove connection and wired together. The company says while installers can configure the system any way they wish, Solarwatt offers complete packages that include all the necessary parts, inverters and cables. These kits are available in 3 kW, 5 kW and 10 kW systems, coming in packs of twelve, twenty and forty modules.
Belgium-based Derbigum is leading a consortium of nine partners to develop new manufacturing technologies and equipment to produce a lower-cost thin-film PV “membrane” which can be fully-integrated into roofing. The bitumen-based waterproof roofing membrane, called the PV-GUM project, is expected to be developed over the next three years, according to Derbigum. Unlike other shingle and tile developments, the PV membrane is more like installing tar paper and is designed for use on flat roofs.
Future Building Industry Needs
Solar roofing shingles and tiles represent a unique collaboration between the building industry and the PV industry. The technical aspects of PVs can’t be expected to be developed by the roofing industry, and the roofing code standards for fire prevention as well as protection from rain, snow loads, hail and wind are beyond the work of the PV industry. But in order for BIPV solar shingles and tiles to be fully adopted by the building industry, they need to be low-cost, easy to install and meet the performance standards for roofing structures in terms of size and installation.
The market for replacing conventional roofing tiles with PV tiles or shingles has already sparked a few smaller traditional roofing companies to enter the BIPV market, following the lead of Dow.
Florida-based EternaTile is marketing a polyurethane, foam molded, interlocking solar tile that is geared to blend with a variety of roofing styles. What makes their tiles interesting is that they were developed by a roofing company which has created four styles of tiles to replace existing roofs with flat asphalt, slate, cedar shake or clay roll tiles.
Another roofing company that has gone solar is UK-based Redland. Their solar PV tile is designed to replace a single course of standard concrete or slate tiles. The company is marketing five products that integrate with eight of the company’s most popular existing roof tiles products for the home market.
The new PV shingle and tile developers are working to better take into account the needs of the building industry. One of the main concerns is the ability of a non-specialized workforce to be allowed to install these shingles and tiles during the course of the normal home construction. In the United States, for example, there are specific ordinances and tight building codes that vary from state to state that dictate which type of contractors – electrical or general - can do what type of jobs.