Photovoltaic panels are being installed on the roof. Bob talks with Jeff Wolf from groSolar about the photovoltaic panels. As sunlight hits the panels, electricity is generated from the photons. That direct current comes down through a wire into the house and is channeled into an inverter. The inverter is in the basement of the home. The inverter converts the direct current from solar power into an alternating current. That alternating current is fed into the main electrical panel and feeds the house with solar power. When the house is not using its electrical energy generated from the panels, the electricity is fed back into the utility grid and spins the meter backwards, creating a credit for the customer. The photovoltaic panels are a clean way of generating energy for the household. Many states have programs to help subsidize the cost of installing solar panels to make them more affordable for homeowners. Many parts of the country are seeing electricity costs escalate by as much as 80 percent so this is a good idea. groSolar operates throughout the country and has a website at www.grosolar.com where people can find out how to work with them to install solar panels on their home anywhere in the U.S. This installation in Norwell is about a $15,000 project and considering the amount of equity it builds in the house, it is something worth considering. With assistnace from state programs, the cost can come down to half that figure, making it a very affordable investment for a homeowner.

Here s another great tip from BobVila.com. When photovoltaics or the conversion of solar energy to electric power came on the scene 30 years ago, it was so inefficient that few thought it could ever power American homes. But the technology has come a long way, and demand for PV systems in the U.S. is now growing at almost 25 percent per year. In sunny California, brownouts and energy crises have pushed the state to set an ambitious goal of putting photovoltaic systems on a million roofs by 2016. The cost of installation can be daunting for homeowners, but government incentives make them much more enticing. The federal government rebates $2,000 per system. In California, the state not only gives a property tax reduction for the cost of the system, it also rebates $2.50 for every system watt. So, a 4-kilowatt system that costs $36,000 only winds up costing the homeowner $24,000. In Florida, homeowners can get $4 per system watt, so the same system costs only $18,000. Add to that the value of the electricity generated by the system which, depending on your area, can be between $250 and $750 per year and photovoltaics start to make a lot more sense. As roof-mounted panels or even integrated into asphalt roof shingles, photovoltaic cells contain silicon wafers which react to sunlight by releasing free electrons. These electrons create direct electric current, or D/C power. The system s inverter switches the D/C to the alternating current, or A/C, that powers our homes. Household photovoltaic systems have become simpler and better adapted to mainstream use now that grid-tied net metering is easier and no battery backup is needed. Any electricity the system generates that s not used in the home gets sold directly back to the power company. In sunny areas, the larger 4-kilowatt systems available today can generate half or more of what the average household consumes. Even where it s not so sunny, photovoltaic systems have become so viable that many forward-thinking developers are pairing them with geothermal heat systems to market the new non-polluting, low-energy home. Find out more at BobVila.com: the ultimate home improvement web site! 2008 BobVila.com

Bob visits the Global Solar factory in Tucson, Arizona, to see how they make their unique solar-electric (photovoltaic) devices. Neil Holstad, president of Global Solar, leads a tour of the plant. The factory itself includes many environmentally friendly features, including abundant day lighting, recycled brick fascia, graywater recycling, concrete containing fly ash, rammed-earth garden walls and energy efficient windows. They go inside the ultra-clean plant and see the unique flexible photovoltaic devices. The flexible material allows the devices to be used in many applications, such as the solar shingles used in the Habitat for Humanity project in Yonkers. Robert Wendt, Director of Technical Operations, shows Bob the materials used to make the solar cells and one of the manufacturing machines they invented for producing them.