Principle of photovoltaic power generation

Solar power generation:

Solar energy is an indefinite source of renewable energy, as the sun has radiated about 500 trillion kilowatt-hours of energy for billions of years and will continue to do so for the next 4 billion years. Solar energy is an energy source that can be used in cookware, water heaters, etc. The main disadvantage of solar energy is that it cannot be produced without sunlight. This restriction is overcome by the use of solar cells, which convert the sun’s energy into electricity.

Solar energy:

It is defined as radiant light and heat from the sun, which is converted into other forms of energy such as electricity and heat using devices such as heaters, solar cookers, and photovoltaic cells.

​Solar panels and mc4 solar cables

A solar panel is a device that responds to light and converts it into electricity. There are numerous kinds of materials that can produce photovoltaic effect, such as: monocrystalline silicon, polysilicon, amorphous silicon, gallium arsenide, copper indium selenium, etc. They work essentially the same way.

A photovoltaic cell consists of two or more layers of semiconductors, one of which is positively charged and the remaining negatively charged.

The photon hits the cell, where it is reflected, transmitted, or absorbed.

When photons are absorbed by the negative layer of the photovoltaic cell, their energy is transferred to electrons in the cell’s atoms.

As energy increases, electrons escape from the outer layers of the atom. Free electrons naturally migrate to the positive layer, creating a potential difference between the positive and negative layers. When the two layers are connected to an external circuit, electrons flow through the circuit, creating a current.

We will now take crystalline silicon as an example to describe the process of photovoltaic power generation. p-n junction can be formed by doping phosphorus type crystalline silicon into N-type silicon. When light hits the surface of a solar cell, some photons are absorbed by the silicon material; ​the photon energy is transferred to the silicon atom, causing more and more electrons to move as free electrons, clumping together on either side of the p-n junction, and creating a potential difference. When the circuit is connected externally, under the action of voltage, the current will flow through the external circuit, producing a certain output power.

The essence of this process is the conversion of photon energy into electricity. There are two kinds of solar power generation, one is formal electricity conversion, the other is direct conversion of photoelectric.

(1) Solar heat conversion method using solar radiation generated by thermal energy generation. Typically, a solar collector absorbs heat from solar panels into industrial steam, which then drives a steam turbine. The former is a heat transfer process. This process is followed by a thermoelectric conversion process, the same as ordinary thermal power generation. The disadvantage of solar thermal power is low efficiency and high cost. The investment is estimated to be at least five times more costly than a conventional coal-fired power plant. A 20-1000 MW solar thermal plant requires an investment of $250 million, 1 kW, with an average investment of $2,000 – $2,500. Therefore, it is suitable for minor special occasions and economical to use on a large scale, which cannot compete with ordinary coal or nuclear power plants.

(2) Photoelectric conversion mode This mode uses the photoelectric effect to convert solar energy directly into electricity. Photoelectric conversion is the basic equipment of solar cells. A solar cell is a cell that converts solar energy directly into electricity through the photovoltaic effect. This is a semiconductor photodiode. When sunlight hits a photodiode, it converts the sun’s energy into electricity and generates an electric current.

Solar panels are a promising new type of power source with three main advantages: permanence, cleanliness and flexibility. Solar cells have a long service life. As long as there is sunlight, solar cells can be invested in long-term use. Compared with thermal and nuclear power, solar cells do not pollute the environment. Solar cells can be large, medium and tiny, ranging from a medium-sized power station with a capacity of 1 million kilowatts to a solar cell for only one home, which is unmatched by alternative energy sources.

Advantages of photovoltaic cells:

Environmental sustainability: photovoltaic cells generate clean green energy without the emission of harmful gases such as COx and NOx. In addition, they do not produce noise pollution, making them an ideal power source for residential areas.

Economic viability: The battery costs very little to operate and maintain. The cost of the solar panels generated is only the initial cost, which is the purchase and installation.
Accessible: Compared to traditional transmission lines, solar panels are easy to install and can be accessed at a lower cost in remote or sparsely populated areas. They are easy to install and do not cause any disturbance to the residential lifestyle.

Renewable Energy: Natural energy is free and abundant.

Cost: Solar panels have no mechanical moving parts, except for some extremely advanced sun-tracking mechanical bases. As a result, the price of solar panel maintenance and repair is negligible.

Disadvantages of photovoltaic cells:

Solar panels are less efficient than alternative renewable energy sources.
Energy from the sun is intermittent and unpredictable, and can only be harnessed when the sun shines. In addition, on cloudy days, electricity production decreases.

​Slow distance transmission of solar energy is inefficient and not easy to carry. The current produced is direct current in nature, and converting direct to alternating current requires the use of additional equipment, such as an inverter.

Photovoltaic panels are fragile and relatively easy to damage. Additional insurance costs are required to ensure the protection of the investment.
How do solar cells work?

Solar panels work by allowing light particles, or photons, to strike electrons in atoms, creating an electric current.

How does a solar cell work?

Silicon crystals are layered into P-type and N-type layers, superimposed on each other. When light hits a crystal, it creates a “photovoltaic effect” that produces electricity.

What does a solar cell consist of?

Solar cells consist of crystalline silicon solar panels, which are a series of interconnected silicon cells connected together to form a circuit.

Can solar energy from photovoltaic cells be harnessed in the absence of sunlight?

No, it should only be used when the sun is shining.

Leave a Comment