Solar panels represent today clean and green technology that can help us reduce energy bills and the carbon footprint of our home or company.
Solar photovoltaic (PV) panels, have the ability to turn the sunlight into clean electricity, which can reduce our dependence on the energy provided by the grid (which is usually produced from fossil fuels).
How Do Photovoltaic Solar Panels Work And Convert The Sunlight Into Electricity?
The most common type of solar panels used today is the photovoltaic (PV) panels, which are mainly made of silicon and are used by homes and businesses to pay less on energy bills.
Being made from melted silicon rocks (silicon is a semiconductor material), the PV panels can turn the sunlight into electricity through the ‘photovoltaic effect’.
The photovoltaic effect is a physical and chemical phenomenon, which refers to the generation of power (electric current) in a material that is exposed to light.
How Are Photovoltaic Solar Panels Made?
Solar panels consist of solar cells, which are the units responsible for power generation. The type and number of solar cells installed on the panel will produce a higher or lower voltage and output of the panel.
I already mentioned that photovoltaic solar cells are made of melted silicon rocks.
A positive chemical element (boron) is added to the silicon to produce a silicon block (ingot) with a positive potential.
Once the silicon ingot has cooled and hardened (it can take up to a few days), it is sliced into thin wafers, and the wafer will be coded on one side with a negatively charged element (phosphorus).
The combination of positive boron infused silicon on one side and the negative phosphorus on the other side, creates a P–N junction (positive-negative junction).
Wires will be painted on the wafer to harness the flow of electrons, and this is how a solar cell is produced.
When the sunlight hits the negative side of the solar cell, some of the negatively charged electrons are knocked loose from their atoms, they travel across the P–N junction to the positive side of the solar cell, where there are holes for them to settle into.
This creates a direct current (DC) flow, which is measured in amps (A).
At the same time, a voltage potential is created between the two sides of the solar cell, and each cell can generate about half a volt.
To increase the voltage, several solar cells are wired together in series (plus to minus) to produce a usable voltage.
An 18V solar panel will have 36 solar cells wired in series to produce that voltage, while a 24V solar panel will use 48 solar cells.
Types of Solar Cells
There are several types of PV solar cells available today on the market.
Monocrystalline cells or Single-crystal cells
Monocrystalline cells are made using long blocks of silicon that are sliced into thin wafers. The manufacturing process of this type of solar cells, is energy-intensive and consumes more materials, but produces a solar cell with higher efficiency.
Monocrystalline solar panels cost more, but they can reach an efficiency up to 23 percent, so they can be used on roofs with a small area.
Monocrystalline solar cells account for a little over 33 percent on the global PV market.
Polycrystalline cells
Polycrystalline cells are made using molten silicon cast into ingots then sliced into squares. The manufacturing process of these cells is less expensive, but the efficiency of the cell is smaller too.
Some of the best polycrystalline solar panels can reach an efficiency up to 20 percent.
Being less efficient but more affordable, polycrystalline solar cells account for about 50 percent on the global PV market.
Thin film cells
Thin film cells are produced by spraying or depositing materials onto glass (amorphous silicon, cadmium-telluride, etc.) or metal surface in thin films.
The manufacturing process of these PV cells, is very simple and less costly because the whole PV module is made in one process instead of two processes (producing the cell and then assembly the PV module).
Thin film modules are less efficient (around 10 percent), but have a lower cost, and they account for about 10 percent on the global PV market.
How To Reduce Your Energy Bills Using Solar Power?
Energy bills can only be reduced by consuming less power in the house or by generating additional power from a different source.
The energy consumption in the house can be slightly reduced by replacing old light bulbs with LED light bulbs, and the old appliances with smart and more efficient ones.
Solar panels. Source.
However, to make a difference on your energy bills, you have to install a solar panel system that can produce additional energy for you.
During the day, the energy produced by the panels will replace the energy provided by the grid, and this will lower the overall consumption of the house, so you will pay less on energy bills.
If you install a larger PV system, you can store some of the energy produced during the day (when the Sun is up) using a battery system, and this will lower your energy bills even more because the stored energy will be used during the night and the next morning.
The Solar Potential On Planet Earth
The Sun has a great potential to produce clean and free electricity for mankind, but today we are harnessing only a tiny amount of this potential to produce power. We rather use fossil fuels that are polluting the atompshere and the environment, instead of increasing the generation capacity for solar energy on the planet.
Solar energy is unevenly distributed across the planet because geography affects the potential of solar (areas closer to the equator receive a higher amount of solar radiation every year).
Solar energy isn’t a reliable source of power because in cloudy days or during the night, the production of solar energy is very reduced.
A total reliance on solar, requires efficient ways to produce electricity (solar thermal can produce power even during the night).
To make solar power more reliable, we have to produce solar power in sunny spots and efficiently transport the electricity to cloudy areas, and we also need to improve energy storage for solar power.
Solar power can become a major source of energy for mankind (like the energy produced from fossil fuels) only if we manage to improve the efficiency of the solar cell (the most advanced solar cell today has an efficiency of about 46 percent).
Commercial solar panels available today on the market have an efficiency between 15 and 20 percent, which means that only 20% of the sunlight received by the panels is turned into electricity.
Conclusion
To power our civilization with solar technology, we need to massively invest to increase the generation capacity for solar, and we also need a large area of sunny space.
The Sahara Desert is a very hot desert located on the African continent with an area of 3,600,000 sq mi (9,200,000 sq km).
If we manage to cover with solar panels such a large area of land, we can make solar power a major source of electricity in the energy mix of the planet, which would severely decrease the use of fossil fuels, and would clean the atmosphere, the soil and the water on our planet.
