Solar energy is the energy which occurs during the transformation of hydrogen in the Sun into helium. This reaction is supposed to last for 5 billion years.

The energy provided from the Sun is15.000 fold of the energy used in 1 year. The total reserves of all oil, coal and natural gas on the earth is equal to sunlight falling to the earth over 20 days.

The average solar energy amount calculated in the earth’s orbit is 1367 W/m². The average annual duration that Turkey is exposed to sun is 2.640 hour/year, and total radiation intensity has been determined as 1311 KWH/m²-year.

The photovoltaic effect composed of the words photo (light) and voltaic (voltage), was first observed by Alexandre-Edmond Becquerel in 1839, and has developed by “AT&T-Bell Labs” after 1950.

Through the serial connection of (30-36) cells producing (0,5V) voltage, solar modules of (12V) voltage create the solar panels connected to each other. Solar modules are semi-conductors converting solar energy directly to electrical energy. Voltage that is the result of the electron flow between (P) and (N) layers of module is used as direct current (12V, 24V, 48V). Besides, it can be used as  (220V)  by being converted to an alternative current through an inverter.

The efficiency ratios of solar panels, which is produced dependent on basic additive materials, outside laboratory are as follows.

Monocrystalline silicon -(Si) --------------------------------% 15–17
Polycrystalline silicon- (Si)----------------------------------- %12–14
Amorphous silicon -(Si)--------------------------------------- %5–8
Gallium arsenide- (GaAs)-----------------------------------%25–28
Cadmium tellüride- (CdTe)----------------------------------%7
Copper indium diselenide- (CuInSe2)-------------------%10

Solar panels are becoming more widespread day by day.

·        Residences away from circuit (farms, mountain houses, accomodation for the summer, villages)

·        Emergency stair lighting (for electricity outages and earthquakes)

·        Urgent communication, first aid, alarm, and security systems

·        Parks, gardens, streets, road lighting systems

·        Communication stations

·        Rural radio and TV stations

·        Telecommunication systems

·        Cathodic protection for petrolium pipelines

·        Sign ligthing systems-

·        Telemetric measurements used in electricity-water distribution systems

·        Protection of metal constructions from corrosion

·        Earthquake and meteorology observation stations

·        Forest watch-towers

·        Agricultural irritagion pumping systems

·        Lighthouses

·        Refregiration appliances for medicine, vaccination and beaches

·        Traffic signalling and warning systems

·        Pool pumping systems

·        Charge appliances