Categories
Choose Language: 
PHOTOVOLTAICS
Weather conditions in the Mediterranean area favor the profitable use of some renewable energy sources, such as solar energy. The abundant solar radiation and the simple structure of the photovoltaic systems offer the possibility to decentralize solar energy, converting it into electricity.
Solar energy is a clean, endless, soft and renewable energy source. It is controlled by no one and represents an endless domestic energy resource, providing energy supply independence, predictability and security.
Photovoltaics, which convert solar energy into electric current, are considered to be the ideal energy conversion systems, since they use the most available energy source in the planet, they don't have moving parts and they produce electricity, which is the most useful energy form.
Our state provides incentives for the installation of photovoltaic systems, the most important being the guarantee of fixed selling price for the energy produced in the power supply network. The harmonization of the institutional framework to that of the other European states is expected to lead to the fast development of the photovoltaic area.
1. What is a photovoltaic system?
It is a system converting the abundant solar energy into electric current. It is one of the fastest developing renewable energy source technologies in the world. In 2004, for example, the photovoltaic production increased by 60% compared to 2003, while it is estimated that the last 5 years the photovoltaic facilities have been steadily increasing by 40% per year. First of all, photovoltaic systems consist of solar collectors, which are big flat surfaces (mostly made of crystalline silicon technology), similar to solar-powered water heater collectors. The photovoltaic system produces low voltage direct current. Thanks to an electronic device, known as inverter, this current is converted into a corresponding quality current, like the one produced by the Public Power Corporation S.A.
2. What is its operation principle?
Solar light consists essentially of elementary energy particles, called photons. Photons contain different amounts of energy, depending on the solar spectrum wave length. For instance, light blue or ultraviolet colors contain more energy than red or infrared colors. As a result, when photons collide onto a photovoltaic element (which is essentially a “semiconductor”), some of them are reflected, others penetrate it and others are absorbed by the photovoltaic element. The latter are the ones that produce electric current. These photons force the photovoltaic element electrons to move to another place, producing this way the electricity phenomenon. This is the simple physics’ principle on which one of the most advanced electricity production technologies of our time is based.
It is estimated that collectors of 10-15 sq. m. surface produce power of one (1) kilowatt (kW). From that point on, the amount of energy delivered by every kilowatt depends on the solar energy received by the collector, but also on the collector technology. Greece represents the ideal country as far as solar energy is concerned.That is explained by the fact that each kilowatt delivers 1,150-1,350 kWh per year. The southest the better: Crete, Aegean islands and Attica are on top of the production list and can reach even up to 1,400 kWh.
4. What are the benefits of the photovoltaics?
When the photovoltaics are exposed to solar energy, they convert 5-17% of solar energy into electrical energy. The exact percentage number depends on the technology used. There are, for example, the so called monocrystalline photovoltaics, the polycrystalline photovoltaics and the amorphous photovoltaics. The latter deliver less energy, but are the cheapest ones. Moreover, the surface coverage varies in each case, depending on the technology. The selection of the appropriate photovoltaic type has to do with the available capital and the investment goals. What is important is that all photovoltaic systems share the following benefits:
- Zero pollution
- Quiet operation
- Reliability and long-lasting life
- Independence regarding fuel supply
- Expandable according to your needs
- Minimum maintenance
The photovoltaic system is the cheapest solution for energy and money saving!
A photovoltaic system consists of:
Τhe collector .jpg)
The inverter .jpg)
The baterry .jpg)
