Solar Panels Resource

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Though the claims of enthusiasts are sometimes overstated, it’s still true that solar power and alternative energy forms are viable and valuable. They’re low-pollution generating, even accounting for manufacturing effects to make the components. They are, in principle, inexhaustible sources of energy. And, those forms of energy don’t require looking to unstable countries to supply raw material.

Solar energy, in the form of light streaming in through the atmosphere from the sun, is converted to usable power by a now-well understood process. Sunlight strikes a PV (photovoltaic) module that respond by generating a current. That electricity flows into a home or business by the same components (wires, circuit breakers) as are used by the utility company.

Wind-generated electricity works by an entirely different principle, but there are some similarities. Wind turns a propeller on a shaft surrounded by a magnet wrapped by a coil of wire. As the magnet turns near the wire (or the wire turns, it doesn’t matter which), electrons in the wire experience a force. That force moves them along inside the wire and that movement creates an electrical current.

Both methods are simple in principle. The sun and wind are there and cost nothing. But converting those energy sources into usable electricity does have costs, along with some interesting physical limitations and engineering challenges.

There are the materials required to build a wind turbine or PV (photovoltaic) module, of course. Creating them is not free. They have to be transported and installed, something which is also not free. And, unfortunately, they are relatively cost-inefficient in terms of the amount of power produced compared to coal, oil and natural gas.

Though improvements have been made, they simply don’t produce the same amount of power as other sources for the same cost.

For example, roughly 1,000 watts per square meter of solar energy reaches the surface (at the equator). But, latitude, weather and other factors often reduce the amount to between 125-375 W/m2. Add in that the efficiency of a solar-powered PV (photovoltaic) module is generally 10-15% depending on how it’s made, and the available energy is relatively low.

Still, given the ability to cover an area the size of a house roof with panels, even that relatively small amount can generate about 1.35 kWh/m2/day. That’s enough to power an average home if the homeowner is careful about usage.

Wind systems have their own unique problems. They regularly kill birds. They rely on almost continual wind. Otherwise, like solar systems, they have to be connected to storage systems. And, they don’t put out the amount of power demanded by most applications.

But even with all these limitations, solar, wind and other alternative energy technologies can sensibly form part of a total power generation strategy. They’re clean, which makes them highly desirable by a society continually striving to improve the quality of the environment. They don’t require importation of oil, or mining of coal or other materials which meet with environmental and political controversy.

With continued technological improvements to increase efficiency and lower costs, they can contribute to supplying electrical demand. It will be sometime before they can reasonably promise to displace a significant percentage of the supply from other sources. But the future is always where the best ideas lie.

Solar power technology has been around in some form or another for thousands of years. Even many modern solar device designs are now decades old. Yet, they have not fulfilled the promise that many hoped. Why? Two reasons: efficiency and cost.

Of the approximately 1,000 watts per square meter of sunlight power falling on the surface of the Earth (at the equator), only a small portion can get converted into usable electricity. Part of that loss is because of internal losses. Of the photons that hit a solar panel, only some will knock loose an electron. Of those, only some will travel down the module and into the device before being recaptured.

The latter effect is an issue called carrier lifetime. The longer the electrons wander around loose, the more likely they are to flow out of the module and down wires to an outlet. Most modules can only achieve in the neighborhood of about 10-15% efficiency. But several companies have raised the efficiency of their devices to as high as 20% by extending that carrier lifetime.

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G-8 Summit leaders commit to dramatically reduce greenhouse gas emissions.

Today’s G-8 Summit Meeting , in the Italian mountain town of L’Aquila (site of the recent deadly earthquake) featured leaders from the United States, Britain, Canada, France, Germany, Italy, Japan and Russia. I am wondering about the leadership of all of these “super 8″ countries” – don’t most of these supposed “industrial” countries including the US have ailing economies and perhaps should be discussing other things? Oh yeah, where is China and India? – they sport growing economies and certainly can have an impact one way or the other on aything that is passed by the G8. How does this G-8 summit resonate with you?

I am hopeful real progress was made and that a serious effort towards reducing greenhouse gas emissions is in store for the future.

Let me know your thoughts…

The image of a large, dark-blue panel atop a rooftop supplying solar-powered electricity is now familiar. Though relatively few homes have them, thousands of magazine stories have been written over the past 30 years accompanied by photos depicting them. Because of their relative rarity, such systems have become regarded as ‘the wave of the future’, with that future always just out of reach. The sticking points are always cost and efficiency.

But there are dozens of cost-effective solar-panel applications available today.

Lawn lights are a popular example. They come in the form of stakes about a foot long with lights mounted on the stake. On the top of the light are small solar panels. They don’t generate much power, but not much is needed for them to do the job. They can be quickly placed anywhere since they require no wires. They can last for years without any maintenance since they use no batteries and the bulbs are ultra-long lasting.

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Using solar cell arrays to produce electricity is a now-familiar application. Most applications that use PV (photovoltaic) modules are still small scale, except for certain experimental stations trying to generate power at the level of utility companies. Still, everything from lawn lights to full power supply systems for homes are available.

But there’s another way of generating electricity, one that’s actually been in use for some time: heating water.

Steam generation plants have been in use for decades. Usually, the water is heated by burning coal, oil or natural gas. The heated water is turned to steam, which drives a turbine. That circular motion can be used to generate electricity.

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The cost of a solar system to power or heat your home can run anywhere from a few thousand dollars to $50,000 or more. The wide range of investment required is the result of many factors.

The amount of sunlight received in different areas varies considerably. Some places like Santa Fe, New Mexico get sunshine an average of 325 days of the year. By contrast, Seattle has only 58 clear days, 82 days that are partly cloudy and 226 days that are cloudy. In the first case, a solar system would provide ample electricity most of the year. In Seattle’s case, the efficiency would be much lower. For those living in Seattle, many more modules would be required to get the needed amount of electricity. That raises the cost.

Costs vary widely, too. Some homes can be covered with panels for as little as $5,000, though the average is closer to $16,000. Larger homes, obviously, require more panels. Usage varies too. If the home remains connected to the utility company grid the cost is lower since some power is still coming from the grid. Having a battery storage system can easily double the cost.

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One of the hurdles any homeowner considering solar generated power has always faced is the high upfront cost. Powering the average home using the sun’s energy requires fairly large solar panels. Most panel systems cover most of the south facing roof of the house. But the cost of the panels alone can easily be around $10,000-$16,000. Add batteries, installation and related costs and you are looking at an initial investment of anywhere from $32,000 to about $50,000.

Many find the cost worth it in order to be independent of the local utility company. In rural areas, power outages are common. Wind storms knock trees onto the lines. Transformer blow outs are common. Many components of such systems are decades old and there’s too little income or other incentives for the power company to upgrade. Having an ‘off-grid’ system provides at minimum a backup during times when the power is out.

Given that the pay back on home solar panel systems can be 20 years or more, some may still see the initial cost as too high. They feel compelled to endure the occasional blackout.

But upfront purchase of the total system isn’t the only option today. There are various loan, lease, rebate or grant systems that can offset part or all of the cost.

Federal tax rebates or outright payments help somewhat. Special legislation in most states allows utility companies to enter arrangements that can reduce the cost of solar power. Some contracts and systems allow for purchasing back any excess solar power. If your system generates more than your home needs, the difference goes into the utility grid. You receive a rebate on your bill.

Many companies will subsidize part of the cost by offering a discount for homeowners who install a solar power system. Not many companies will pay you to purchase less of their product or service. But the crazy quilt of regulations in electricity generation gives the utility company a financial incentive to do just that.

There are a few companies just now starting up that promise to lease equipment. That opens the option of lowering the major share of the upfront cost of solar systems. Just as when leasing a car, the total cost over time may be slightly higher. But lowering the initial investment from $50,000 to $1,000 puts a solar power system within reach of many more people.

Most people today own their home for less than seven years. That’s one of the major reasons mortgage companies can offer the flexible rates and terms that have become common in the past 15 years. That fact affects the feasibility of installing a solar system as well.

Most people who only expect to own their home for, say, five years are going to be reluctant to sink $50,000 more into it. Installing a solar system raises the value of a home, certainly. But it rarely raises it enough to get a new buyer to cover the total cost. But leasing means the equipment can be returned after a set period of time. That opens up new options.

With changes in technology and financial arrangements, solar power systems are becoming more attractive. Investigating all the options may well put one within reach for you.

Solar power, particularly when it’s used to provide home electricity needs, may seem like a relatively recent invention. And it’s true that large, cost-effective panels that form the core of most systems have only been in use for about that past 30 years. But the underlying method they employ goes back to 1839, when it was discovered by Becquerel. He found that shining sunlight on an electrolytic cell would produce a current.

Other scientists built on that work. In fact, while Albert Einstein is most well known for the Theory of Relativity, he received his 1921 Nobel Prize for something quite different. According to the Nobel organization it was ‘for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect’. His paper on the subject was written in 1905.

The photoelectric effect is essentially similar to what solar power enthusiasts and workers know as the photovoltaic effect, the principle Becquerel first found. When light, in this case from the sun, strikes certain materials it knocks loose electrons from their associated atoms. Those moving electrons create a current that can flow through the material to provide electrical power.

Those materials today are typically some type of doped silicon. ‘Doping’ is another way of saying that other elements are deliberately introduced. In other applications, those impurities would be undesirable. In solar power, they’re essential. Pure silicon has its uses, but it’s not a good conductor of electricity. Adding phosphorus in just the right way, for example, turns them into semiconductors.

Certain specialized applications use gallium-arsenide or other materials, instead of silicon. But because of their relative rarity the cost is much higher. Silicon is a major component of ordinary sand and hence plentiful.

The silicon-phosphorus compound is arranged in layers, then connected to a grid to enhance the flow of electricity. It reduces the resistance losses. Then terminals are installed to allow for the electricity to flow into the home electrical system. The whole assembly is covered with glass to protect it and forms what’s known as a PV (photovoltaic) cell. Those cells are then arrayed into a module. Modules can then be connected together into a complete system.

Those modules comes in various sizes that determine how much electricity they generate. All other things being equal, the larger the area, the more power they can produce. Naturally, the larger panels tend to cost more.

Though the solar energy reaching the surface (at the equator) is about 1,000 watts per square meter, not all of it is usable energy. A square meter is a square whose sides are a little larger than three feet – it’s about 10.7 square feet. Apart from losses due to latitude, atmosphere, dust and other natural factors, the modules themselves only convert with about 10-15% efficiency.

The growth of solar power as a practical energy production method depends heavily on increasing that efficiency and lowering the costs of production. To a degree, that efficiency is bound by certain difficult-to-get-around physical constraints, so most of the research efforts involve attempts to lower the manufacturing costs.

When or if that happens, solar power applications may well become even more commonplace in homes and businesses than they are today.

The standard solar power system used to provide electricity today consists chiefly of two components: PV (photovoltaic) panels and a storage system. The PV (photovoltaic) panels generate the electricity. A solar storage system stores any excess for later use when there isn’t enough sunlight to power all your needs.

Batteries

That storage system is usually in the form of a large array of batteries stored in a vented, safe location such as a basement or specially constructed room. Though batteries are optional, in order to be completely ‘off grid’ some kind of storage system is needed and batteries are almost universally used.

There are two basic kinds of batteries used in most systems: lead acid and nickel cadmium.

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The idea of heating your home with the sun is hardly new. Since the dawn of humankind the sun has been used to provide needed warmth. But modern technology has completely transformed the way that can be done, even from the methods used a few generations ago.

In the 1920s some municipalities supplied hot water to homes by large storage tanks that were heated by the sun. As the unit cost of electricity and gas decreased, such applications became relatively too expensive to compete. But old ideas often become new again, with a twist. Modern hot water heating systems using solar power have now been in use for more than 30 years.

But what’s even newer are ways of heating the home using solar energy that go well beyond simple windows. It’s certainly possible to just allow sunlight to stream into a window. But that often leads to areas of the home that are too bright. It generates areas that are too warm, while others receive too little heat.

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