The performance of a solar cell is measured by its efficiency. The most important parameter determining the efficiency is the percentage of the transformation of the received energy into usable electricity. However, the light in certain wave lengths may be transformed into electricity; the remaining major amount is either absorbed by the structural component of the cell or is reflected. Therefore, a efficiency of a typical solar cell is about 15%, today, which means that it transforms only one sixth of the received energy into electricity.

It is possible to obtain maximum efficiency in every season, by directing the solar panels towards the sun in different angles depending on the seasons. By means of the winter inclination of 60º, which is generally valid for Turkey and because of the characteristics of the panel glasses, freezing or snow accumulation is prevented.

The alternative energy systems may be designed on-grid, off-grid or green-line (network supported) based on the project requirements. The power of the sun battery systems connected to the network changes between a few kW to a few MW. As these systems may be in the size of a high power plant, the more general application is in the form of small power systems in the buildings. The systems independent from the network are preferred in the places where the network is completely unavailable. As long as the climate data are sufficient, these systems can be more profitable than the investment required for connection to the network, when even if the first investment costs are considered. In these systems, batteries are required for storing the generated electricity to enable use of it at nights or when the energy is not generated. While the battery capacity is adjusted, the climate data of the region, the electricity devices to be used and the period of use are considered.

The general application fields of the systems independent from the network can be listed as follows:

• Communication stations, rural radio, wireless and telephone systems
• Cathodic pickling of petroleum pipelines
• Protection of the metal construction (bridges, towers.) from corrosion
• Telemetric measurements performed in electricity and water distribution systems, aerial observation stations
• Illumination inside and outside the premises
• Operation of electric devices such as TV, radio, refrigerator in the mountain houses and in houses far from the settlements
• Agricultural watering or water pumping for house-hold use
• Forest observation towers
• Light houses
• First aid, alarm and security systems
• Earthquake and air monitoring stations
• Mountain houses, farms
• Special applications such as ships and caravans

The annual total sunshine duration of Turkey is 2640 hours (7.2 hours per day), and the average total radiation intensity is 1311 kWh/m 2 year (3,6 kWh/m 2 per day). As can be seen from the figures, our country should start benefiting from alternative energy resources without losing time.

solar energy references

complete references list