The sun has the potential to produce heat, facilitate chemical reactions, and generate electricity. It generates more than 170,000 terawatts of energy in a day when it shines on this planet. That amount is 10,000 times the daily energy use in the world. But how does solar energy work from the sun to your appliances? In a moment, we are going to unravel that.
Interestingly, the cumulative solar incident on planet earth is more than the world’s current and projected energy needs. Appropriately harnessing this energy could see the world have sufficient power for its future requirements.
There is a lot of expectation that more people adopt solar energy in this century. That is because it is a renewable resource that is inexhaustible. Besides, it has a non-polluting characteristic. Unlike sources such as natural gas and fossil fuels, solar energy does not harm the environment.
The unfortunate thing is that solar energy is not cheap to collect, convert, and store. Therefore, its full exploitation faces limits in many places.
Step by Step Guide on How Solar Energy Works
1. Absorption of solar radiation
The first step is the absorption of energy from the sun by the photovoltaic cells. Solar photovoltaic (PV) is a high tech invention that has been around for quite some time. In the 19th century, Edmond Becquerel discovered the potential of electric sparks production when the sun radiation hits certain materials. It is the general principle through which solar energy work.
In the late 1800s, there was the creation of the first PV cells. That was after researchers realized that it was possible to harness the photoelectric effect discovered by Becquerel. In the middle of the 20th century, Bell labs scrutinized the technology more and created silicon PV cells.
The Photovoltaic cell
A PV cell has two layers of silicon crystals, which happens to be the most crucial components. It is a semiconductor material. However, doping, which involves intentionally adding materials to the crystallized silicon, improves the conductivity.
The PV cell consists of boron doping on the bottom, which works with silicon for a positive charge. The top layer consists of phosphorus doping, which provides a negative charge.
The P-type and n-type semiconductors have a surface between them. The movement of electrons in this region generates an electric field. Through it, electrons flow in a single direction from the bottom layer to the top layer. The surface is known as the P-N junction.
When radiation from the sun reaches the cell, its energy kicks electrons in the two layers. They become loose, and since the layers have opposite charges, the electrons move from the negative.
An external circuit offers an ideal path through which the electrons flow to the p-type section from the n-type. Solar cells come in three types.
Polycrystalline cells
The solar panels consist of molten silicon curved into square, lower production cost and an efficiency of around 20%. They account for approximately 50% of the PV market in the world.
Single crystal cells
They consist of long tubes and curved into slim wafers. These cells account for around a third of the world’s PV market. Although it is an energy-intensive process, it is highly efficient in converting the incoming radiation into electricity. Panels consisting of single-crystal cells can be around 23% efficient.
Thin-film cells
Unlike the other types where there is the assembly of individual cells, the thin film involves making the entire panel. It consists of a deposit of thin films of amorphous silicon or other materials onto a metal or glass surface. The efficiency and production cost are low too. They account for around 10% of the PV market in the world.
In the past, most of the Photovoltaic modules were common in off-grid systems. You could find them in residential houses, water pumps, and cell phone towers. However, over the past few years, there has been tremendous growth in solar power into the grid. It is not only in the United States but also in other countries.
2. Conversion of alternating current into direct current
A typical solar module consists of a metal frame, a layer of silicon cells, a glass covering. Additionally, there are wires to facilitate the flow of current from the cells. Whenever there is an interaction of the silicon cells with sunlight, electrons begin to move. It is the motion that triggers the flow of electricity.
Other than the silicon solar cells, a standard solar panel has a glass covering. It protects the silicon PV cells, thus increasing their durability. Beneath the glass interior, the panel has an insulating sheet that prevents heat dissipation and protects the panels’ interior from humidification. The insulation helps in maintaining the high performance of solar panels because high temperatures reduce efficiency. Solar modules come with an anti-reflective layer that increases solar radiation absorption and maximizes silicon cells’ exposure to sunlight.
After the absorption of solar radiation and the conversion into electric energy, the electricity is in direct current. However, most electrical appliances use alternating current. Therefore, the conversion of the direct current to alternating current is necessary. Solar panels have a gadget referred to as inverter. It is responsible for converting DC into AC, after which the power flows into the electrical wiring of the building.
3. The flow of the excess electricity into the grid
After converting electricity into alternating current, it flows to power electronic devices in the building, including the lights. However, during peak hours, there is energy that remains after a household meets its requirements. It is the electricity that flows into the local grid.
Although most people might know how solar energy systems work, there is confusion when you bring the aspect of grid connection. Any residential premise connected to the electrical grid has a utility meter. It is through it that the utility company tracks the power it supplies to your home.
In the United States, net metering is accessible to most homeowners. It is a solar incentive that substantially enhances the economic aspect of solar. With net metering, it is possible to feed power into the electrical grid when your solar panels generate excess electricity. You receive credit on your bills through which you can draw additional power when there is less production.
Therefore, you can consider net metering as a free storage solution for homeowners who use solar energy.
There are two major systems of solar energy production. There are rooftop solar panel systems, and the large scale PV systems. Electricity from rooftop systems first meets the needs of the site. The grid supplies extra electricity if the need arises. In case the residential or business produces excess power, the electricity flows into the grid.
Unlike the small scale, large scale systems feed the power into the grid. It can operate at the highest capacity when there is a lot of demand. These systems are more resilient to harsh weather due to the nature of the PV technology. Additionally, in large scale PV systems, solar energy works even when a section is faulty.
Effectiveness of solar systems on cloudy and rainy days
Although solar energy is more efficient when there is full sunlight, the panels work even in cloudy or rainy conditions. It is possible to have enough power generation even when the clouds block the sun. It is the sunlight that powers the solar panels and not the heat. Therefore, electricity generation during low temperatures is as effective as that in hot areas. A good example is Germany, which leads to solar energy production, yet it is not warm or sunny most of the time.
Maintenance of solar systems
Solar systems require less maintenance. However, you might have to change the inverter several times throughout the entire life. Like the solar modules, inverters to have a warranty ranging around 5-15 years. Inverters usually stop functioning at once, and thus the only option is to replace them. The case is different from solar modules, whereby they continue working as the efficiency decreases.
However, technological advancement is taking care of the issue of replacing inverters. These days, every solar panel comes with its microinverter, unlike the single central inverter for the entire system. The micro-inverters can last longer up to 25 years. The advantage is that in case one of them fails, the system continues functioning.
Once you install your solar panels, you have a guarantee that they will last for decades. They usually come with a warranty of 25 to 30 years. Solar energy systems work even beyond the stipulated time frame since their parts are durable.
Does solar energy save on cost?
There are several determinants of the amount you can save when you use solar energy. One is the solar system’s size. If you have a large system, then you are likely to generate more power. Therefore, there is less reliance on energy from the utility company. Other determinants include the amount of power you consume per month and solar panels’ exposure to the sun’s radiation. Besides, your local utility company’s requirements can impact the amount that the solar system can save you.
A good thing with the solar energy system is that it works compatibly with other applications. As the system provides power for your uses, it can feed the additional energy to the grid. Therefore, it reduces the cost of utility bills. Additionally, it is possible to store excess solar energy and use it in case of a blackout or in times of low production.
