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Solar Energy
Photovoltaic Panels:
Photovoltaic panels are joined together to create a solar array.
A power inverter (top panel) converts solar power from DC to AC; a charge controller (bottom panel) regulates the solar powered system.
Here's how the process works:
First, the photovoltaic panels -- or array -- collect sunlight and converts it into solar energy. The energy is then stored in special batteries inside the home before being sent to a power inverter that converts the energy from DC to AC. Once the power has been converted, a charge controller monitors and regulates the entire system.
PV Panel Manufacturing
And what makes PV panels work? Here's a brief overview:
First, the manufacturer molds treated raw silicon into blocks that are slide into thin, square wafers. The wafers have impurities on both top and bottom surfaces, that causes the silicon to become energized when penetrated by sunlight. The interval electrical field created in turn creates electricity that can be used immediately or stored for later usage. The wafers are mounted and connected together in a grid sandwiched between tempered glass panels and forged into a panel than can withstand winds of 120 mph -- as well as almost any weather condition. Finally, wiring is added to the back of the panels.
Homeowners considering the purchase of PV panels should consider their overall needs before investing. For example: deciding whether battery storage capability is desired or how much of the home will be powered by the solar system. Many manufacturers offer complete packages that make the installation easier and more economical -- and now, even offer plyable panels that can be rolled directly over a rooftop.
Some Of The Reasons We Need Solar Energy
Climate
An IntroductionAccording to the National Academy of Sciences, the Earth's surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. There is new and stronger evidence that most of the warming over the last 50 years is attributable to human activities. Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although exist about exactly how earth’s climate responds to them. Our Changing AtmosphereEnergy from the sun drives the earth’s weather and climate, and heats the earth’s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse.
Without this natural “greenhouse effect,” temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth’s average temperature is a more hospitable 60°F. However, problems may arise when the atmospheric concentration of greenhouse gases increases.
Estimating future emissions is difficult, because it depends on demographic, economic, technological, policy, and institutional developments. Several emissions scenarios have been developed based on differing projections of these underlying factors. For example, by 2100, in the absence of emissions control policies, carbon dioxide concentrations are projected to be 30-150% higher than today’s levels.
Changing Climate
What Are Sinks?A sink is a reservoir that uptakes a chemical element or compound from another part of its cycle. For example, soil and trees tend to act as natural sinks for carbon – each year hundreds of billions of tons of carbon in the form of CO2 are absorbed by oceans, soils, and
Impacts
Rising global temperatures are expected to raise sea level, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also affect human health, animals, and many types of ecosystems. Deserts may expand into existing rangelands, and features of some of our National Parks may be permanently altered.
Actions
Today, action is occurring at every level to reduce, to avoid, and to better understand the risks associated with climate change. Many cities and states across the country have prepared greenhouse gas inventories; and many are actively pursuing programs and policies that will result in greenhouse gas emission reductions.
At the national level, the U.S. Global Change Research Program coordinates the world's most extensive research effort on climate change. In addition, EPA and other federal agencies are actively engaging the private sector, states, and localities in partnerships based on a win-win philosophy and aimed at addressing the challenge of global warming while, at the same time, strengthening the economy. For more information, see the US Climate Action Report (U.S. Department of State, May 2002).
This Home employs 26 BP Solar 120 watt solar modules. Their system is tied to the grid and they feed power to PG&E during the day when they generate more power then they use (net generation). This system includes an emergency battery backup, which can power a few critical loads like the refrigerator and a few basic lights and appliances for 8-12 hours, in the event of a rolling blackout or any natural disaster.
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