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Solar Power

Solar power is gained from the sun in a variety of ways. It is generally considered a unique renewable energy source separate from such resources as wind, geothermal, and hydropower. However, energy from the sun is actually the ultimate cause for wind, waves, and other energy sources of the earth. In that sense, solar energy is also the source of wind and water power.

Of course, certain methods of harnessing solar power are more direct than others. When it comes to discussion of solar technology, there are several ways in which today’s world can take advantage of solar radiation:

• Solar Thermal Technology
These heating systems make use of solar thermal collectors to heat water or air for different needs. Some are designed for warming swimming pools, others for creating hot water for daily use, and still others for heating the space within a building. These systems will generally include some form of storage so that the heat can be utilized even after the sun goes down.

• Photovoltaics
The field of photovoltaics (PV) concerns itself with converting sunlight directly into electricity. It does this through the use of semiconductors. The most commonly used of the semiconductors is silicon. Numerous solar cells comprised of this material are used to make up a photovoltaic panel. As the sunlight hits the panel, electrons are excited, creating DC power. This power can be converted into a more useable AC power through the use of an inverter.

PV panels are commonly seen in large scale arrays used to supplement or entirely replace reliance on city power. They are also seen on many small items, such as calculators and batter chargers.

• Solar Concentrators
These technologies use mirrors and receivers for the concentration of sunlight. The light is intensified and transformed into heat which can simply be used to heat food and water. The heat can also be converted into electricity in a couple different ways. Steam turbines are one option, while utilizing a heat engine to drive a generator is another.

Concentrating solar power (CSP) systems collect solar energy in three main ways. Linear systems focus sunlight onto a receiver tube, which heats a fluid and creates a super hot steam. The tubes may be shaped as troughs or they may reflect the light back up into a parallel surface which contains the fluid.

A dish/engine system has a dish which concentrates sunlight onto a receiver mounted immediately in front of it. The receiver is part of a power conversion unit which also includes the engine or generator. This engine takes the heat and converts it into electricity.

The third type of CSP system is known as a Power Tower. This system has a receiver mounted at the top of a tower. Many mirrors surrounding the tower direct sunlight to the receiver. These mirrors are known as heliostats.

• Solar Lighting
Solar lighting can involve simple passive design as well as a more technologically oriented hybrid structure. The passive design is basically a skylight which allows natural lighting in during the daytime. Hybrid technologies are part natural lighting and part electric light. They utilize concentrators to collect and distribute sunlight through optical fibers.