The combination of green roofs with rooftop solar panels can provide a quick and easy way to boost solar cell efficiency right now, making it more cost effective for property owners to invest in a rooftop solar installation without waiting for new technology breakthroughs to hit the market. Though at first glance it may seem that solar panels and vegetation don’t mix, the solar industry has been coming up with new rooftop infrastructures that enables greenery to thrive between the photovoltaic modules.
Solar Panels that Tiptoe Through the Tulips
One main concern when siting solar panels on a green roof is enabling enough water to reach the plants. In conventional solar installations, the modules are mounted on concrete slabs and that prevents water from distributing evenly across the roof. The solution, according to the International Green Roof Association, is to mount the panels on boards that double as drainage layers, a system that is becoming common in the two green roof hotspots of Europe, Germany and Switzerland.
The other concern is excessive shade from the solar panels. So far, though, the research indicates that while some stunting does occur, the addition of shade to a green roof can improve the overall health of the roof by promoting biodiversity. Shade from the solar panels provides a habitat for plants and various kinds of critters that don’t thrive in full sunlight.
Green Roofs Boost Solar Cell Efficiency
The company Green Roof Technology has just introduced a combination solar panel-green roof system it calls “Sun-Root,” and its chief Jörg Breuning sums up the concept nicely: “Heat is the enemy of energy production.” Excess heat prevents photovoltaic cells from operating at peak efficiency. While solar researchers are developing new advanced solar cell technologies to get around that problem, green roofs have a proven ability to cool down surface temperatures. The natural cooling effect of green roofs can boost photovoltaic efficiency significantly, by up to 16 percent according to one study.
Green Roofs for the U.S. Military
Given the alacrity with which the Department of Defense is preparing for the end of oil by adopting alternative energy and energy conservation technologies, it should be no surprise that green roofs are already sprouting up at military facilities around the country, including a new green roof at DoD’s brand new LEED gold billion-dollar office complex in Virginia. It’s only a matter of time before the solar-green roof crossover hits the military market, and from there it’s just a short hop over to the mainstream mass market.
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Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.