Healing Appalachia: Sustainable Living through Appropriate Technology

1. Solar Photovoltaics

I have been installing solar electric systems in Kentucky and Tennessee for over a dozen years now, from small cabin systems to large house systems. Many of my clients have environmental concerns as a major motivation. Photovoltaic panels are the cleanest electricity generators that can be used almost anywhere . They offer a practical alternative to coal-generated electricity and the ravages associated with coal mining. My home’s electricity comes from solar electric panels and I encourage and assist others to do the same. Bob Fairchild, director, Eastern Kentucky Appropriate Technologies, Dreyfus, Kentucky Many applications of photovoltaics (PVs) are touched upon in this chapter: domestic electricity, energy-conserving lighting, PV accessories such as water pumps, and “net metering,” a procedure for integrating solar-generated energy into an electric grid system, thus reducing the cost of self-contained solar systems. Other chapters deal with such topics as passive solar heating of residences, greenhouses and other seasonal extenders, heating water and cooking, and solar-charged electric cars. ASPI (Appalachia–Science in the Public Interest) has three separate PV systems, one on its solar house, one on the nature center, and one system for the office. The office system was intended to be simply a solar charging station for the ASPI electric car, but we soon realized that it could also furnish electricity to run the office. This utility intertied system allows excess solarCHAPTER 1 Solar Photovoltaics generated energy to flow into the local utility company’s grid (see figure 1.1). The importance of electricity in the modern world cannot be overemphasized—and the massive Northeast blackout in the summer of 2003 underscored that fact. But must electricity be generated by environmentally flawed fossil-fueled or nuclearfueled power plants in a world beset with global warming partly caused by power plant emissions and with unsolved nuclear waste problems? Solar, wind energy, and microhydropower systems offer clean, renewable sources of electricity. These technologies can be used at the residential level, but at some financial cost. Getting one’s power from the sun, collecting rainwater, and growing one’s food in greenhouses all combine to make the dream of a “living ark” come true, and this model can provide the springboard for achieving community interdependence. Two movements seem to be occurring in the complex PV field: the decentralized generation of electricity through PV units and the centralized pooling of surplus energy from these units so it can be transferred to places in need. Decentralizing 28 ❖ Healing Appalachia Fig. 1.1. Utility intertied system. A system such as this makes net metering possible. some generating sources while retaining transmission lines and utility grids for the welfare of a larger community challenges basic concepts of appropriate technology as self-sustaining independent systems apart from the larger world community. Solar PV can offer independence from the electric grid, but it becomes more economical when interconnected with the modern world. Perhaps we can join the best aspects of self-sufficiency and interdependence in a balanced way. DOMESTIC ELECTRICITY The potential for renewable sources of electricity at relatively low cost is at our own back doors and roofs. AstroPower of Delaware was for years a leading producer of solar cells and modules made totally in the United States. They offered single-crystal 60-, 75-, and 120-watt modules with thirtysix series-connected cells and tempered glass glazing with aluminum frame and weather-tight junction box. The largest module came with a twenty-year warranty. Hopes were running high that these larger workhorse types of PV generating modules would become even more affordable in the near future when the company faced financial problems, was delisted from the NASDAQ in 2003, and filed for bankruptcy. AstroPower was purchased in 2004 by General Electric (GE Energy), which is making a commitment to renewable energy following its purchase of Enron Wind in 2002. Solar shingles are also available. Recently attention has focused on companies such as Uni-Solar (a wholly owned subsidiary of Energy Conversion Devices, Inc.) that are producing PV roofing shingles that can also serve as a weather-resistant roof covering. In 2006 both solar shingles and PV panels are commercially available for about $4 or $5 a watt. It is anticipated that prices will decline for both. Economies of scale ought to apply to both technologies in the near future as solar growth in 2004 was up by 15 percent. These shingles come in 7 by 1 foot...