The Photovoltaic conversion of solar radiation involves the conversion of solar radiation energy into electrical energy. This conversion is performed in the solar cells. Solar cells are made of special semiconductor materials, have a simple structure with no moving parts, do not pollute the environment and have a long shelf life. As the cell is the basic structural unit of the living organisms, a solar cell is the basic unit of each solar power plant.
Considering that these plants have no harmful products during the electricity production, and have good efficiency (20 – 40%), they represent a significant potential for the future. Since the amount of energy that reaches the earth’s surface is extremely high, such plants in sunny areas (e.g., Sahara) can supply a large number of users with electricity.
The solar power plant is a power station that converts solar radiation into electricity using the solar cells. It consists of solar cells grouped into solar modules, inverter that converts DC to AC voltage and transformer – through which electrical energy is transferred to the distribution network. All operations are automated and controlled by an appropriate computer program.
The most commonly used solar modules are made of monocrystalline and polycrystalline silicon, and less often of thin film materials, such as amorphous silicon and CdTe. Solar modules from monocrystalline and polycrystalline silicon are suitable for areas with predominantly direct sunlight, while the solar modules of thin film materials are suitable for areas with diffuse solar radiation.
Depending on the local climatic conditions, there are fixed, uniaxial and biaxial rotating solar power plants in the world. Fixed solar plants are commonly installed in areas with continental and moderate continental climate, while rotating power plants are more suitable for regions with tropical climate.
- Fixed solar power plant – The plant in which the solar modules (solar panels) are mounted on fixed metal brackets at the optimum angle to the horizontal plane with orientation to the south. Their main disadvantage is that modules don’t follow the position of the sun in the sky, so they do not produce the maximum amount of electricity on an annual basis.
- The uniaxial rotating solar power plant – Solar panels are placed at the optimum angle to the south and they follow changes in the position of the sun during the day, by turning around a vertical axis from east to west.
- Biaxial rotating solar power plant – The position of the solar modules is adjusted to the sun during the year, by turning around the vertical and horizontal axes.
For several years, growth of solar power plants was driven mainly by European deployment. Now, worldwide growth of solar PV has shifted to Asia, especially Japan and China, and to other regions all over the world: Canada, Australia, India, Israel, Chile, South Africa, Thailand, South Korea, and the United States. Currently, the world’s three largest solar power stations are:
- Topaz Solar Farm – Capacity of 550 MW (California, USA)
- Desert Sunlight Solar Farm – Capacity of 550 MW (Mojave Desert, California)
- Longyangxia Dam Solar Park – Capacity of 320 MW (Qinghai, China)
There are many advantages of solar power plant, and here are some of the top benefits: they help to slow / stop global warming, save money, provide energy reliability and security, have great shelf life and allow energy independence.