4:54 p.m., Oct. 10, 2008----Steven Hegedus, a scientist in UD's Institute of Energy Conversion (IEC), championed the ecological and financial benefits of using solar cells to generate residential electricity and shared information from his own home's conversion to solar power at the University of Delaware Association of Retired Faculty (UDARF) luncheon held Oct. 7 at Clayton Hall.

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Hegedus began his presentation by talking about the history, work and goals of the IEC, noting that while it plays a role in training graduate and undergraduate students, it's an entity supported entirely by the money it brings in from the research and development of thin-film photovoltaic solar cells and other photonic devices.

After showing some slides of IEC labs and devices, Hegedus then defined thin-film solar cells and showed three examples, in the form of silicon wafers in a rigid frame, a thin-film flexible “roll-to-roll” sheet and a thin-film solar cell made of glass.

“There's been a huge interest in thin-film solar cell development techniques the last several years, with each manufacturer trying to develop a unique angle or advantage,” Hegedus said. “I've been in this field for 30 years, and I didn't think it was going to take this long.

“I expected that this was going to happen right away, in the '80s,” he said, “and it's sort of disappointing that it's only now just catching on. But the combination of increased environmental awareness and energy costs, as well as the growing awareness that the green economy finally has a future, all have contributed to the fantastic amounts of money that is now being invested in solar, both by small companies and very large corporations.”

Hegedus listed several applications of thin-film solar cells, from their use by the military to power field soldiers' batteries, to their use by explorers and backpackers to power equipment. He then talked about their use in roofing materials and windows and explained how using semi-transparent thin-film solar cells for windows could serve the dual purpose, from a homeowner's perspective, of generating electricity and offsetting installation costs.

“The advantage of this kind of window, from a cost point of view,” Hegedus said, “is that it allows property owners to subsidize some of the cost of the solar module with the glass for the window, as the window was going to go in anyway.”

Hegedus then defined solar electricity and outlined both its environmental and long-term economic benefits. “Solar electricity is the generation of electricity directly from sunlight,” he said. “You don't burn anything and there are no moving parts. It's got a higher viability and a longer lifetime. There are no emissions, no smog and no mercury; and the fact that it's operating with free fuel means that it incurs essentially zero operating costs.

“[Solar cells] also are modular,” Hegedus said, “so you can install five watts, 50 watts, 500 watts, five megawatts specifically where you need it to serve an application. You can't build a 100-watt steam-powered plant or a nuclear plant, but you can put up a 100-watt module wherever you need it.”

Hegedus added that the portability and ecological footprint of solar power lend it universal acceptance and said that its modular flexibility makes it a natural choice for environmentally conscious home and business owners.

“There's no geopolitical monopoly on sunlight,” he said, “and everybody likes solar. Nobody wants a nuclear power plant next door, but nobody will complain about solar modules in the neighborhood.”

Before sharing specifics on his own solar cell array--from its installation to its output and draw to its predicted cost savings over time--Hegedus showed trends in solar power usage worldwide, with Germany and Japan leading the way, and examined factors that typically keep homeowners from making the switch to solar power--namely the initial costs associated with materials and installation and the lack of incentives by policymakers.

Hegedus also dispelled several myths that have dogged solar power and, to some extent, sabotaged its widespread use.
He then explained the difference between energy and power, gave an algorithm for accurately predicting a system's annual power output, and discussed some limitations of solar power.

“The energy payback for today's crystalline silicon modules is about two years,” Hegedus said, in conclusion. “That means you put the module outside in the sun and after about two years you've made as much energy as it took to make the module. And because it will last from 20 to 25 years, that means you've got 23 years of net positive CO2-free energy coming from that module.”

Hegedus capped his lecture by encouraging listeners to make the leap to solar power and by giving two Web sites--[www.findsolar.com] and [www.delaware-energy.com]--where those converting their homes could find more information on manufacturers, installers and incentive programs.

“My point is that now is a great time to install today's tested and proven technology in your yard, in your home, in your business, and to take advantage of the fact that you're going to be gaining on the steadily rising utility rates by doing so,” Hegedus said. “Don't wait. Today is a fine time to go solar!”

The program closed a question-and-answer session.

Article by Becca Hutchinson
Photos by Kathy Atkinson