Solar Power - What Is Solar Power?

Human use of the sun's energy may seem like a recent phenomenon. But, in fact, solar energy has been in use in various forms for thousands of years.

Apart from the obvious fact that the sun provides the energy for plants to grow that feed us, there are more technological uses that go back millennia.

The ancient Greeks knew how to harness steam power, some of it generated by solar radiation. Pre-industrial, they regarded the devices as amusing toys, primarily. But some applications were taken seriously. Archimedes designed and had built a large magnifying-type glass that was used to set enemy ships on fire. The Romans adopted some of this technology, as they did much of Greek science.

Thermometers, heat storage containers and many other devices were created over the centuries that relied on energy from the sun. Over time, those devices became more sophisticated and more diverse.

In 1839 another big leap occurred when Becquerel discovered the photovoltaic effect even though it would take another 100 years for devices based on it to become practical.

When sunlight hits certain materials, it causes the electrons in the atoms to get knocked loose from their associated atoms. Electrons moving within material constitute an electrical current. When that current is connected to a circuit, the power generated by the electrical flow can light bulbs, heat water or power a computer. Try using a gratzel solar cell and a solar data center along with a solar security systems and finally invest in solar hot water.

 
But electricity isn't the only form of solar power.

In the 1920s some public heating systems used large storage tanks to trap solar energy. The heated water was then supplied to homes. Eventually, those systems couldn't compete economically. Gradually, the cost of gas and electricity decreased to the point that it was below those systems' operating costs.

Those systems fell into disuse and were eventually forgotten. But the technology existed as a mainstream method, not a crank alternative. It worked and was, for the time, a cost-effective solution.

Now there are hundreds of viable applications of solar power, which in one way or another convert sunlight received at the surface to power devices, heat water and supply other energy needs.

Satellites have used solar panels and associated technology to supply needed power. The systems are expensive, but compared to the total they're a very small fraction of the cost. Closer to home, the same kind of technology powers phones or lights along some highways.

And it isn't just esoteric applications that benefit from solar power either.

Solar heating systems are employed in thousands of homes. Though solar powered electrical systems are less common than utility power, they are in wide use in rural areas where people want or need to supplement their supply. Many cabins in the Pacific Northwest are too far from the utility company lines to get electricity that way.
 

 
Not all devices or systems are hugely expensive, either. Low-cost solar powered lawn lights are dotting many homes today. Calculators powered by tiny solar panels are so cheap they're often given away as promotional items by advertisers.

Solar power can't yet compete with large scale electricity generation by big utility companies. But costs are coming down and the applications are growing. It's had a long past, but the future of solar power looks bright.

Solar Power - How Solar Power Works

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.

Make your own power

Buy yourself a small solar panel. For about $100 you should be able to get one rated at 12 volts or better look for 16 volts at marine supplies or 4wd store.

Buy yourself a battery. We recommend rechargeable batteries.  Get any size deep cycle 12 volt lead/acid or gel battery. You need the deep cycle battery for continuous use. The kind in your car is not suitable and is really just a a cranking battery--just for starting an engine. Look for bargains, the cheapest ones should cost about $50-60, try ebay. A smaller yet rechargeable battery is your best bet.

Get a battery box to put it in for $10

 Buy a 12 volt DC meter. any electronics outlet has them for around $40. A DC meter that matches the voltage of your battery and a DC input. These products will allow you to convert your energy from the panel and apply them to power sources around your home

 Buy a DC input. I like the triple inlet model which you can find at a car parts store in the cigarette lighter parts section for about $20. This is enough to power DC appliances, and there are many commercially available.

But if you want to run AC appliances, you will have to invest in an inverter. This will convert the stored DC power in the battery into AC power for most of your household appliances. I bought a 240 volt 140 watt inverter for around $120. Count up the number of watts you'll be using (e.g., a small color television(=60 watts) with a VCR(=22 watts), Always get a higher wattage than you will actually need, allow around 20% above and beyond you requirements. Cheap inverters of many sizes can be had online.

Use a drill to attach the meter and DC input to the top of the box. Be very careful to only work with one wire at a time and connect the first wire to the negative input first. Use the same procedure to connect the DC inlet and the solar panel to the battery itself.

Use insulated wire to attach the meter to the wingnut terminals on the battery. Connect the negative (-) pole first. Only handle one wire at a time. Connect the DC inlet to the battery in the same way. Connect the solar panel to the battery in the same way.

Close the lid (I use a bungee cord to keep it tight). Put the solar panel in the sun. It takes 5-8 hours to charge a dead battery; 1-3 hours to top off a weak one. It will run radios, fans, and small wattage lights all night, or give you about 5 hours of continuous use at 115 volt AC, or about an hour boiling water. This system may be added on to with larger panels, inverters, and batteries.
Options: A pop-up circuit breaker may be added between the positive terminal and the volt meter. Some of you will want an ampmeter as well. The panels I recommend have built-in bypass diodes, but I recommend charge controllers for people who have panels without diodes. Another option is a voltage regulator, which is not necessary for a system this small, but a larger system would require one.

Shopping for a solar power system can be an exciting time for many people, but as with any substantial investment

For more tips on how to build your own solar panel, click on the link below in the resource area. Don't forget to check out the other articles on ehow while you are here.