By Cindy Atoji Keene
For solar energy project manager Eric Lorenz, his favorite part of every installation is the familiar “thump” sound when flipping the final switch. It’s the moment when solar panels go online and begin operation, converting sunlight into electrical current. “It’s a reminder that there is one more renewable energy system harvesting solar energy,” said Lorenz, who is part of S+H Construction’s Renewable Energy Division, where he collaborates on the design of residential and commercial photovoltaic and solar thermal systems.
Q: How did you get interested in solar energy?
A: My interest in solar began while forming a solar startup in Maine with two college buddies during our final summer co-op. My friends had come up with the idea after having trouble finding a summer job. Our very first project was quite large for a startup. We installed two solar tracking arrays mounted on steel poles in a field abutting a lake. Up to this point, I was having a great time working with two good friends, but the best was yet to come. Due to the safety built into these systems, we each had an opportunity to ‘flip’ a switch. Standing at the house, we looked into the field and witnessed the two large arrays slowly align themselves with the sun. It was this moment that hooked me on solar.
Q: How has the technology of solar panels improved?
A: Solar, like any other technology, has advanced greatly over the years. On the performance side, photovoltaics (PV) panels, or modules, for residential applications were first available well under 100 watts and had ratings well below 10 percent efficiency. Current modules are available at 230-260 watts and are rated with efficiencies up to 17 percent. In recent years, panels have become more aesthetically appealing, available with black frames and black backings, allowing them to blend in more with most roofs. A few manufacturers are producing framed and frameless transparent modules that can be used as vertical or sloped glazing. My favorite application for these modules is for solar awnings. Just imagine sitting outside under a solar awning enjoying the outdoors and knowing that the roof just above you is harvesting energy and delivering it to your home.
Q: Geographically, is Massachusetts a good solar energy location?
A: Massachusetts is considered a good location for solar because it receives on average approximately four to five kilowatts a day of solar energy at ideal conditions. (Typical energy efficient homes use anywhere from five to 15 kilowatt hours in a day). In comparison, the Southwest, which has the highest solar density in the U.S., receives approximately six or more kilowatts. Although Massachusetts is not on the top of the list, we have weather working in our favor. One thing that certainly helps us is that our temperatures are milder, which results in better performance of the equipment we install on roofs.
Q: What was one of your more challenging projects?
A: Rebuilding an old solar thermal system and creating solar collectors that supply heat to both a swimming pool and the home’s hot water system. Since the pool isn’t used in the winter, I needed to figure out how to be able to turn that off in the cold weather and vice versa; during the summer, the pool becomes the priority. Figuring out how to manage that was a difficult task, but it was finally achieved through different control systems.
Q: How is extreme weather affecting solar energy installations?
A: A few years ago, the roof snow-loads in the state increased, which now requires us to strengthen our racking systems. In areas where there’s higher likelihood of hurricanes or tornados, there are similar ramp-ups in structural requirements. But generally speaking we don’t see wind damage very often – but we do see squirrels chewing wires, or near a golf course, balls hitting panels. One of the funniest things I’ve seen is in coastal regions is having a lot of birds defecting on the arrays.
Q: You recently installed a solar hot water system in your house. How’s it working?
A: It’s awesome; the type of system I have has a drain back, which means that when the system isn’t running, the water flows into a tank reservoir where it can be heated by the sun. I’m getting an average of 90 degree water before the water even enters the hot water system. And when there’s a lot of sunshine, the water sitting in our storage tank is 130 degrees, so the supplementary conventional hot water heater probably won’t need to even turn on. It’s very efficient. I believe in solar and I work with it, so I want to live with it and understand it better.
Q: Is solar energy a do-it-yourself proposition?
A: The technology can be easy enough for someone who knows what they’re doing, but a licensed electrician needs to deal with the electrical components. Laying out the panels in an efficient and attractive way can be difficult – the racking that holds the panels needs to be structurally sound and everything needs to be level and plumb.