Solar cells - perspective energy source for the new millenium
Solar energy - the most promising clean energy source for new generations. Sun has been shinning for about 5 billion years (without malfunctions) and it will continue shinning for another 4 to 5 billion years.
The first PV system applications developed were applied as an energy source for satellites and later for orbital stations in space. Nowadays, photovoltaic systems are applied as an energy source in many cases. Most commonly applied photovoltaic systems can be found in remote and rural areas where no public grid is available. However, quite often grid-connected systems are constructed in urban areas. Photovoltaic systems are an excellent solution to electricity production regardless of your whereabouts - even at high latitudes of Himalayas or in Antarctica photovoltaic systems have been build. According to loads connected to the system and to the basic design principles, the following photovoltaic systems are used - direct coupled photovoltaic systems (systems without batteries - water pumping systems for example), standalone photovoltaic systems, grid-connected photovoltaic systems, hybrid systems (e.g. PV - wind or PV - diesel systems), concentrator photovoltaic systems. The applications below depict use of photovoltaic systems as an energy source in many interesting ways.
Photovoltaic power plants - Solar modules are nowadays parts of large standalone or grid-connected systems. Large photovoltaic power plants (MW range) have beeing constructed in Germany, Spain, USA, Italy, Netherlands etc. Worldwide more than 250 large PV power plants with peak power 1 MWp or more (each plant) are connected to the public grid(s).
Electricity source for protected areas - an example of application would be a natural park or other environmentally protected area. Negative influence on the environment is avoided by application of photovoltaic systems in such areas, which cannot be achieved by use of public grid.
Telecommunication devices supplied by PV systems - Many telecommunications systems can be found in impassable areas making them difficult to reach by ground. The locations can be most difficult to reach during winter with snowfalls increasing the possibilities of systems malfunctions. Many of the systems are used in critical applications, such as railway signalling, telecom facilities for rural areas, marine lights, TV transmitters to name but a few.
Alarm and control systems power supply - Numerous fire alarms, burglar alarms and other alarm systems could be powered by photovoltaic systems. Usually an alarm system is connected with a remote monitoring communication system and it is powered by solar cells. Such systems operate independently of a grid power supply, therefore, they can be used in remote areas or in situations, where high reliability is required. The other important group of systems, that could gain a lot from photovoltaic systems, are light signs, marine lights, airport landing lights, heliport lights etc.
Use of PV systems in medical applications - Application of photovoltaic systems has proved very suitable for power supplying medical clinics in rural areas. Photovoltaic systems power lighting, sterilisation equipment, vaccine refrigerators, air conditioning etc. Installation of such systems is most widespread in different African countries. The systems are usually designed as complements to small wind systems or diesel generators, which are used for backup power supply at night or in emergency, such as emergency surgeries, and for x-ray power supply.
Street lighting - PV street-lighting is the most applicable in rural areas, where no public grid is available.
Solar powered aircrafts - HELIOS project was a part of NASA's ERAST programme (Environmental Research Aircraft and Sensor Technology). It was developed by NASA and Californian company AeroVironment Inc. ERAST programme develops pilotless solar powered airplane technology. The HELIOS construction is based upon its predecessors like NASA's solar plane Pathfinder, which was successfully tested a few years prior to HELIOS. In the test flight on 13th August 2001, HELIOS reached the height of almost 30,000 meters.
Other interesting application examples - photovoltaic systems can also be used as an energy source in oil drilling platforms or for parking meters to name but a few. Often photovoltaic systems are realised in combination with wind or diesel generators wherever a 24 hours functioning of power supply system is necessary. Some other very important application examples are: PV systems for caravans and boats, rural electrification, solar powered vehicles (cars, boats) etc.
