Scott Salter asked:

Solar power is a green energy source available in almost every corner of the globe and of course has been literally available since the dawn of time. Solar energy is produced by using photovoltaic (PV) cells that capture the energy of the sun and then convert it into electricity. The basic unit of the system is the solar cell and these cells are connected together into modules. Solar power is an increasingly attractive energy technology because photovoltaic modules produce no pollution, have an expected life of twenty years and require little in the way of maintenance. As such, solar power is increasingly being looked to as a long term solution for the world’s current global warming problems.

One of the more popular solar power applications is the use of solar energy to power the home. Home solar power systems are a great way of using an alternative yet abundant energy source. They provide clean, renewable energy and require little maintenance after the initial installation. Home solar power systems convert sunlight into electricity through the use of solar panels. For an average home about ten watts per square foot of electrical energy will be gathered per day, but this can vary depending on the size of the solar panels that are being used. On days with a more intense sun, more electricity will be produced.

Electricity generated by your solar panel array passes through an inverter to convert it from DC to AC electricity. Electrical wiring connects the solar panels to the controller, then to the meter box and ultimately to the electricity company via the existing electricity grid. Little additional equipment is needed other than the panels, controller and inverters, wiring, and the roof mounting system. Electricity produced by the solar cells that is not used immediately in the home can be returned to the power grid. When this happens the electricity meter literally spins backwards as energy is being passed back to the grid.

In the case of standalone residential power systems (i.e. where there is no integration with the existing electricity grid) it is important to also have a battery (or batteries) and an associated battery charger. A battery charger enables you to charge a battery (or batteries) in order to store electricity. Prior to the advent of solar battery chargers, solar power was only useful during daylight hours. You need the ability to not only utilize solar energy, but also store any excess electricity for use during the night. A solar power battery charger can be bought from a wide range of retail outlets and online stores, whom specialize in solar energy supplies.

These types of self sustaining solar power systems for the home are increasing in popularity worldwide as energy prices start to soar and environmental concerns take on a sharper priority.

Solar Power for homes

Arnold Hexden asked:

Solar power has many more uses around your home than just solar heating. The technology has made significant advances and you can now cook, heat your pool and even refrigerate your groceries using energy from the sun. However, your solar home may have issues that you may be unaware of. In this article, we’ll talk about the economic and environmental benefits and drawbacks of using solar power.

The biggest benefit of solar energy is that the fuel is free and the source is unlimited. There is little to no maintenance required with solar panels because there are no moving parts. In fact, most manufacturers include warranties on their products that are good for up to twenty-five years. In the event of a blackout, solar power is not affected. That means that during extreme storms, your family can still enjoy all the comforts of your solar home.

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Anita Van Wyk asked:

Many of us know that solar energy is good, but few really
understand why.
Therefore, I compiled a comprehensive list of solar energy
advantages and disadvantages that will enable you to make an
educated decision whether on not Solar Power is right for YOU.

Solar Energy Advantages
1. Saves you money
After the initial investment has been recovered, the
energy from the sun is practically FREE. The recovery/
payback period for this investment can be very short depending
on how much electricity your household uses. Financial
incentives are available form the government that will reduce
your cost. If your system produce more energy than you
use, your utility company can buy it from you, building up a
credit on your account! This is called net metering. It
will save you money on your electricity bill if you have one at
all. Solar energy does not require any fuel.

It’s not affected by the supply and demand of fuel and is
therefore not subjected to the ever-increasing price of
gasoline. The savings are immediate and for many years
to come. The use of solar energy indirectly reduces
health costs.

2. Environmentally friendly
Solar Energy is clean, renewable (unlike gas, oil and
coal) and sustainable, helping to protect our environment.
It does not pollute our air by releasing carbon dioxide,
nitrogen oxide, sulphur dioxide or mercury into the atmosphere
like many traditional forms of electrical generations does.
Therefore Solar Energy does not contribute to global
warming, acid rain or smog. It actively contributes to
the decrease of harmful green house gas emissions. It’s
generated where it is needed. By not using any fuel,
Solar Energy does not contribute to the cost and problems of the
recovery and transportation of fuel or the storage of
radioactive waste.

3. Independent/ semi-independent
Solar Energy can be utilized to offset utility-supplied
energy consumption. It does not only reduce your electricity
bill, but will also continue to supply your home/ business with
electricity in the event of a power outage. A Solar
Energy system can operate entirely independent, not requiring a
connection to a power or gas grid at all. Systems can therefore
be installed in remote locations (like holiday log cabins),
making it more practical and cost-effective than the supply of
utility electricity to a new site. The use of Solar
Energy reduces our dependence on foreign and/or centralized
sources of energy, influenced by natural disasters or
international events and so contributes to a sustainable
future. Solar Energy supports local job and wealth
creation, fuelling local economies.

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Paul Calhoun asked:


Introduction:

Global warming impact to our quality and cost of living is large and very catastrophic. Homeowners are well aware of the increasing energy costs to heat, cool and illuminate their homes. The increasing costs of oil and other fossil fuels are daily headlines. The insatiable demand for energy to fuel world growth guarantees that the cost of these limited fuels will continue to increase. Political/economic forces will determine the rate of increase for fossil fuels. In addition, the increasing cost of global warming using fossil fuels is slowly being recognized.

The world is slowly beginning to understand the urgent need for renewable energy sources. However, each of these alternative energy sources brings major advantages and disadvantages. An example is wind generated energy. Wind energy is available to the whole world and generates electricity competitively with fossil fuels. The technology is understood and easy to apply. But, there are big objections to a windmill in “my back yard”. Also, the number of birds and bats that will be crushed with wind power generation is not a warming thought. Wind technology will be a component of our energy solution. However, because of the above concerns, we need other major solutions to meet our demand for energy sources.

This search leads us to solar energy. The amount of sun energy striking our world in one day is sufficient to supply our energy demands for a year. We will not run out of this source in the foreseeable future. The major barrier to harnessing solar energy has been cost and convenience. For example, drying clothes in a dryer is easier than hanging clothes on an outside line, thus convenience precluded efforts to find more energy efficiency. We can convert solar energy to electricity but with a major capital cost. Greater acceptance and use of solar energy will lead to lower cost.

Solar Energy:

Energy from solar energy can be divided into two major categories:

Passive Solar Energy: This technology ranges from clothes drying in the sun to solar heating for hot water and many other passive techniques. All are important for our present and future quality of life. The technology is well understood and can be implemented as economics and space conditions allow.

Active Solar Energy: One of the active solar energy technologies is converting solar energy directly into electricity. It is called photovoltaic cell or PV. This is a device that converts light into electricity using the photoelectric effect. The first working solar cells were constructed by Charles Fritts in 1883. These prototype cells were made of selenium and achieved efficiencies around one percent. The silicon solar cell was created in 1954. The solar cell has benefited from the development of silicon semiconductors.

Physics of Active Solar Energy:

The physics of photon to electricity conversion is well understood by physicists. The basic model is of a photon from the sun which strikes the cell material and excites electrons that emit electricity. This model is simple compared to the complexity of modern day semiconductors. The major variables of PV electrical generation are cell material and impurities in the cell material.

Manufacturing Technology for Active Solar Energy:

Primarily single crystal, high purity silicon has been used to generate photon to electricity conversion. The manufacturing techniques for single crystal silicon and limited quantities of pure silicon impose a high cost for PV devices. Shortages of refined silicon have been hampering production worldwide since late 2004. This shortage persists to this date and has slowed PV growth. New materials are starting to come forward which should lower the PV materials hurdle.

Efficiency growth of Active Solar Energy:

Since the silicon PV invention in 1954, cheaper fossil fuel prices largely removed solar power from the public consciousness. Annual growth of electrical generation by PV ranged from 10 to 20% percent throughout the 1980′s and 1990′s. Worldwide installation of PV reached 1000 megawatts in 1999. Manufacturing costs for PV arrays has been dropping 3 to 5% over the recent years. This cost drop began to expand the use of PV electricity generation. Total peak power of installed PV was around 6000 megawatts at the end of 2006. Installed PV is projected to increase to over 9,000 megawatts in 2007. The average lowest retail cost of large photovoltaic arrays has declined from $7.50 to $4.00 per watt between 1990 and 2005.

PV materials have also been improving in recent years. The most recent materials approach is to process discrete cells on silicon wafers cut from multi crystalline ribbons which form thin films. This approach is the least expensive of known technologies. This group of technologies includes amorphous silicon cells deposited on stainless-steel ribbon, cadmium telluride (CdTe) cells deposited on glass, and copper indium gallium dielenide (CIGS) alloy cells deposited on either glass or stainless steel substrates. The efficiencies of these new materials are currently at 20%. Many researchers are working to improve the efficiencies. An added advantage of the new thin films is that they are flexible and are currently being used in roofing materials.

Current Trends in Generating Active Solar Energy:

Commercial businesses like Google, IBM, BJ’s Wholesale, Estee Lauder, Kohls, Target, Tiffany & Co., Wal-Mart are installing PV solar energy. From “big box” discount giants to high end commercial businesses PV solar energy is finding acceptance in 2007. The most recent retail-outfitter to become part of this trend is Macy’s, which announced earlier this month that it will install solar powered systems on 26 stores throughout California. These leading companies are turning to solar power because it makes good business sense and supports their environmental initiative. Creative financial arrangements allow these companies to afford the upfront capital costs and payback their loans with energy savings. So what does all this mean to the average home owner? PV Cost per Kilowatt (kWh):

In the California market, where state incentives and net metering are in place, PV electricity prices are dipping below 11¢/kWh, on par with some utility-delivered power. Moreover, according to the U.S. PV Industry Roadmap, solar electricity will continue this trend and become competitive by 2010 for most domestic markets. The outlook is very positive for PV generation of electricity. Once the capital investment is made, the cost of PV electricity is equivalent to fossil fuels and will continue to decrease.

Cost of PV Installation:

The cost of installation is the major barrier that has to be overcome for widespread PV acceptance. Around 59% of world solar product sales installed in the last five years were applications that are tied to the electricity grid. Solar energy prices in these applications are 5-20 times more expensive than the cheapest source of conventional electricity generation. This premium is well beyond the reach of the average home owner.

Fortunately, there are financial models coming forward to enable the consumer to finance PV solar installation and pay for this installation with the electrical savings. In order to make these financial models successful, federal and state incentives are needed and the installation should be connected to the electrical grid. These connections allow the home owner to sell back electricity when excessive amounts are available and to receive electricity when solar conditions do not allow sufficient electricity. Only fifty percent of our states have modernized to allow on-grid PV solar energy.

Berkeley, California is leading the way to enable it citizens to save electrical cost and meet environmental needs. Here is how their plan works. A property owner hires a city-approved solar installer, who determines the best solar system for the property, depending on energy use. Most residential solar panel systems in the city cost from $15,000 to $20,000.

The city will pay the contractor for the system and its installation, minus any applicable state and federal rebates, and would add an assessment to the property owner’s tax bill to pay for the system. The extra tax would include administrative fees and interest, which would be lower than what the property owner could obtain on their own, because the city would secure low-interest bonds and loans. The tax would stay with the property even if the owner sold, although the owner would have to leave the solar panels. The property owner would save money on monthly Pacific Gas & Electric bills because electricity generated by the solar panels would partly replace electricity delivered by the utility. After the assessment expired, the solar panels, of a simple technology that requires little or no maintenance, would continue to partly replace PG&E electricity.

The Berkeley plan is a map for the rest of the world to allow us affordable electricity and meet our responsibilities to the environment.

I have a BS and MS in Metallurgical Engineering. Thirty six years spent in the development of semiconductors. Business experience in start up business plan. Currently, an oyster farmer and interested in helping the environment by deploying solar energy. Please visit my Web Site http://www.charlestonenvironmentalhelp.com

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nathan asked:

Solar Power History

“I have no doubt that we will be successful in harnessing the sun’s energy… If sunbeams were weapons of war, we would have had solar energy centuries ago.” These are words of Sir George Porter (December 1920 – August 2002), Nobel Laureate in Chemistry, which today is a reality. The energy which is derived from the sun and responsible for practically all life on earth is today harnessed for generating heat, light, power and electricity for meeting global needs for alternate energy resources. Yet the concept and use of solar energy is not new. Early Greeks, Native Americans and Chinese have used it to their benefit by orienting their home and hearth toward the sun for centuries. The term solar power has today become synonymous with solar energy which is obtained by converting sunlight to electricity.

While the application span of solar energy now encompasses the domestic (including cooking and heating), commercial, industrial, farming, aviation and surface transport sectors, there are several technologies which are in place to generate this type of natural energy. In fact, solar energy has now found its place in every day use items like cars and calculators.

Back in historical times, solar energy may not have been known by any name, but its use has always been the backbone of agriculture ever since man learned to till the land and grow food or crops. We have seen the importance of this energy in medieval Europe where farmers deployed elaborate agricultural strategies to get the maximum out of sunlight for the wellbeing of their yield. Even today, sunlight optimization is the primary agenda for anyone who is involved in farming or gardening, starting from planning their planting schedule, strategizing row orientation, altering plant heights between rows, etc.
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