| Electricity From Solar Energy |
View Comments
| Environment - Environment |
| Written by Walter Hull |
| Wednesday, 17 June 2009 08:33 |
|
One of the more significant emerging technologies with solar energy has been photovoltaic (PV) electricity. Photovoltaics use special materials to convert solar energy directly into electricity. This electricity can be used immediately or stored in a bank of DC batteries.
One of the more significant emerging technologies with solar energy has been photovoltaic (PV) electricity. Photovoltaics use special materials to convert solar energy directly into electricity. This electricity can be used immediately or stored in a bank of DC batteries. The materials involved with photovoltaic technology were developed in recent times. Under the influence of solar energy, these materials will release electrons. This in turn creates a voltage potential and a flow of electricity. All of these reactions take place on the atomic level without moving parts, and so a photovoltaic panel is also called a direct energy conversion device. Historically photovoltaic panels were limited to space age technologies. They are used in satellites and the space stations where they reliably and continuously convert solar energy. As an added bonus, the Sun's radiation is at least 50% more powerful once we break into Outer Space. In more modern times, photovoltaics are used in residential homes and locations far away from the Electrical Grid. The reason is that the cost of running power transmission cables can quickly exceed the cost of installing a photovoltaic power array. If you are greater than mile from the Electrical Grid, then it is probably a good idea to investigate solar energy. The greater this distance, then the easier it becomes to make that decision. There are two types of radiation that are important and contribute to solar energy. The first is beam radiation, which are the direct rays of the Sun. Beam radiation is the strong warm rays we feel on a clear sunny day. The second type is diffuse radiation, which is scattered in all directions. A good example is the radiation we experience on a cloudy day, which won't exactly blind us and isn't very strong. On a cloudy day, then, diffuse radiation contributes the majority fraction of the total solar energy. In order to use photovoltaics wisely, one should be in an area abundant with solar energy. Deserts are obvious candidates, in addition to semi-arid and tropical climates. Northern and coastal climates are tougher decisions due to extensive cloud cover, fog patterns, and rains in the winter. Each case should be considered respectively, however, as not all coastal climates are the same. Photovoltaic panels come in a variety of sizes, voltages, and constructions. They can be wired in series or parallel to meet your system's needs. 12 volt and 24 volt configurations are common, while 48 volts and greater are used for heavy duty installations. Most photovoltaics in production are about 12% efficient. This may not seem like much, but keep in mind that the cost of solar energy is zero, and they will have typical service lives of 25 years. Ultra high purity silicone semi-conductor materials are involved in the modern construction of photovoltaic panels. Due to this, photovoltaics can be an expensive option for using solar energy. New materials are under development, however, and are aimed at lower the manufacturing cost. Cadmium Telluride based solar panels are one such technology. The price of solar panels is expected to fall in coming years if these new materials proceed. Using photovoltaics to convert solar energy can be a complicated decision. One must consider the cost of local Utility's rate of electricity, and know the solar energy data for their location. In some cases, as with distant properties and transmission cables, the decision can be easy. But in most cases, an investigation of the payback period will be necessary to know if one is making a cost effective decision. In times of uncertainty and surging fuel costs, the simple piece of mind of energy independent technologies may be well worth the effort. About the Author: Walter Hull is a recognized expert in solar energy power systems. For a short time you can get his free checklist to solar energy from your own backyard. |