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Photovoltaics
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Each year the sun provides 15,000 times more energy than current worldwide demand. Think only those living in the sunbelt benefit from photovoltaic energy applications? Not so. Though local conditions do impact efficiency of such systems, a PV application may be a good choice even if never considered previously. Technology gains are constantly being made and even municipalities such as Portland, Oregon and the state of North Dakota offer incentives for PV installation.
Photovoltaic (PV) cells convert sunlight directly into electricity. This technology has become integrated into many services we use daily. PV panels are often found powering highway signs, fans in remote backcountry toilets, satellites in orbit, calculators in school, and can power your entire home.
PV cells are made of silicon semiconductors similar to those used in computer chips. Sunlight produces electricity by causing the electrons to flow through the semiconducting material. PV cells are usually built into larger panels that hold around 40 cells. These cells are then mounted on frames that measure around 2.5 feet by 5 feet and put together to form an array. An array will vary in size depending on needs. Panels are set up on unobstructed south facing roofs or spaces with maximum solar gain. Large numbers of panels can be combined to form a power plant.
There are a variety of systems available to suit many needs and budgets. They can range from a simple direct system dedicated to running one appliance or machine up to an entirely integrated system utilizing batteries and disconnected from the utility grid.
Use and need of electricity depends on several factors. Some homes could be run on 10 panels that produced 1 kilowatt (1,000 watts) each. Another similarly sized home that was more reliant on electricity may need three or four times the amount of panels to meet their needs. In a residential setting panels can be added as needs grow, all the while being tied to the grid ensuring constant power. Many people start with a small system and slowly add panels to eventually be completely self-sufficient or even sell power back to the grid.
Presently residential photovoltaic panels produce electricity from less than 20% of the sun that reaches them. As the PV manufacturers increase this efficiency, fewer panels will create more electricity which should lower the cost of creating electricity from the sun.
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Before you buy... Windows
Everybody loves windows. What is the attraction? We love the connection to the outdoors, to be engaged in nature yet comfortable indoors no matter what the weather is outside. In addition to bringing views, light, and aesthetic value to a home, windows contribute to two vital energy systems: daylighting and heating.
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