| If you have ever used mirrors and a magnifying glass | | | | more directly and make heat transfer unnecessary. |
| to start a fire, you have a pretty good idea of how | | | | This heat is used to power what is known as a Stirling |
| concentrated photovoltaic systems operate. Using | | | | Engine, which operates by the expansion of gas or |
| these elements, sunlight is concentrated, amplified and | | | | fluid as it is heated. Fresnel lenses, similar to those used |
| focused onto concentrated photovoltaic solar panels | | | | in video projectors, may also be used to concentrate |
| or a transfer fluid duct, creating the heat needed to | | | | sunlight into a small area. |
| power an electrical generator. | | | | However, the heart of the most efficient systems is |
| Although the use of magnifying glasses to intensify | | | | the concentrated photovoltaic panel onto which this |
| solar rays may go back 2200 years and parabolic | | | | sunlight is directed. Rather than using the sun's energy |
| troughs were first used to boil water was in 1866, it | | | | indirectly to boil water or run a Stirling Engine, |
| wasn't until the late 1960s that these two elements | | | | concentrated photovoltaic systems generate electrical |
| were combined. Built in northern Italy near the city of | | | | energy directly. This essentially cuts out a step, |
| Genoa, this early attempt to concentrate solar energy | | | | creating much greater efficiency, since when heat |
| produced 1 megawatt of electrical energy by heating | | | | must be transferred, some is inevitably lost in the |
| steam to over 1,000 degrees Fahrenheit. | | | | process. |
| Today, the largest concentrated photovoltaic solar | | | | The only drawback is that concentrated photovoltaic |
| power facility is located in Southern California. | | | | solar panels must be mounted on some type of |
| Generating over thirty-five times the amount of energy | | | | tracking device so that the sun's rays remain focused |
| supplied by the Genoa plant, the Solar Energy | | | | on the panels' surfaces over the course of the day. |
| Generating System (SEGS) puts out 354 megawatts | | | | Currently, new alloys are allowing for efficiencies |
| and is still one of the largest solar power stations in the | | | | beyond 40%; it is projected that further advances in |
| world. | | | | solar energy technology will eventually allow an |
| These facilities are constructed in a number of | | | | efficiency rating of up to 50% within the next few |
| different ways; parabolic troughs are only one of them. | | | | years. |
| There are also dish systems, which use solar heat | | | | |