Our earth is full of natural resources which can be exploited for the benefit of mankind. Sunlight or solar energy is one of the most abundant natural resources that our planet has and can effectively be utilized for solving the ever growing energy problem.
Electricity has long been produced using the burning of fossil fuels which have severely damaged our earth. With depleting fossil fuels and for a safe future for the earth, people have now turned towards more reliable, sustainable and renewable energy resources to produce electricity and meet the excessive demands.
Sunlight is abundant in most parts of the world, with some parts receiving more than the others. In many of the countries like Pakistan, you can have sufficient sunlight everyday throughout the year. According to research, the total amount of solar energy reaching the surface of earth at a time is 173,000 terawatts; this amount of energy is 10 times the energy that we need. This makes solar energy quite a reliable resource of energy for most of the countries.
Pakistan also has great solar potential and receives an average of 5.5 kW of solar energy for every square meter and has sunlight availability of 8 to 9 hours every day. An estimated value of the solar potential that Pakistan has rounds up to 100,000 MW. If this potential is effectively utilized Pakistan will no longer have to face any sorts of energy shortage. You can explore more possible solar solutions in pakistan.
In order to produce electricity and meet the energy demand , this solar energy must be captured and converted into usable electricity However, harvesting sunlight and utilizing it to produce electricity is not that simple and easy. Great efforts and studies have been conducted to transform this idea into reality and humans have been quite successful in it and are making advancements and progress every other day.
How can you utilize solar energy?
The Sun is the main source of solar energy. But how does this solar energy reach the earth? The sun releases small packets of energy known as photons which strike the surface of the earth as solar energy. Theoretically, the number of photons that strike the earth every hour are sufficient enough to produce electricity for the whole world for one year. If it was that simple, how pleasant it would be!
Present statistic show that solar energy only shares less than 2% of the energy consumption chart. Harvesting solar energy and converting into electricity is not only difficult but costly as well. However, great advancements have been made in the field of solar energy.
Solar energy can be effectively used by designing a proper system to capture the energy packets and then convert them into electricity. The main component of this system are the photovoltaic cells which combine to make the solar panel.
What are Solar Panels?
The photons striking the earth cannot be used as is. They need to be captured properly and then their energy can be used. For this purpose, photovoltaic cells (PV) or solar cells have been designed. Photovoltaic cells are designed by layering silicon, phosphorus and boron. Phosphorus is used to obtain the negative charge while boron is used to obtain the positive charge. The flow of positive and negative charges is necessary in order to produce current. The layers of phosphorus and boron serve as the positive and negative terminals of a battery and help the current to flow.
Photovoltaic cells are arranged in an array to build up PV modules which are then electrically connected to produce photovoltaic arrays. The best thing about photovoltaic cells is that the efficiency per unit area of the cell will not be affected by the size of the array. This means that 5 square km array and 5 square meter array will have the same efficiency per unit area which is usually not the case for most of the renewable energy resources; their efficiency is directly related to their size.
How do the Solar Panels Operate?
The solar panel is an array of photovoltaic cells which are designed to capture photons and produce electricity. But how does this actually happen? In layman terms, solar panels collect sunlight and convert it into electricity which can be used to power up loads. This collection and conversion is an intricate and detailed process.
1st step (Establishing an electric field)
For the photovoltaic cells to perform what they are designed to do, it needs to establish an electric field. An electric field is established by the presence of opposite charges. The opposite charges in a cell are developed by the doping of silicon sheets which are then sandwiched like in a semiconductor.
The top layer is phosphorus with an extra electron making the layer negatively charged while the bottom layer is boron with the absence of an electron or commonly known as hole, thus creating a positively charged layer. The junction between the two layers now has an electric field. Now, if this sandwich receives an extra electron, the established electric field will push it out of the junction thus causing the electron to flow.
2nd Step (Flow of current)
Flow of electron is called current. The cells have been designed such that they allow the flow of electrons outside the cell and transform into usable energy. The cell has conductors on the sides which collects the flow of electrons and transfers it into a wire making it a usable directional current.
Sunlight will hit the top layer of the solar panel which means multiple photons will hit the surface of the panel and introduce excess electrons in the panel. This electron is absorbed into the panel and thus will initiate current to flow when the electric field will pull these free electrons in one direction. This entire process of absorption of photons and production of current by the solar cell is called the photovoltaic effect which is the basis of solar panels.
3rd step (Conversion of DC current into AC current through an inverter)
The inverter is designed to take DC electricity from the solar panel and then convert into AC electricity through the use of high speed electromagnetic switches and multiple electronic components. They are designed to not only convert direct electricity into alternating electricity but also provide system statistics and ground fault protection. The statistics that they provide include the energy production, voltage and current of the system and track the highest point of power.
4th step (Net metering)
The net metering system ensures that your house will always have a backup from the utility’s grid for times when the solar panel system is not producing sufficient electricity. However, there will be days when the solar panel system will be producing more electricity than required. In such cases, through the net metering system, the excess electricity can either be fed back to the grid or can be compensated for the utility’s electricity that you have used. The net meter will bill you on the difference of the electricity received from the grid and the amount sent back to the grid.
How is usable electricity produced from solar panels?
We have seen above that directional current is produced by a solar panel. Directional current is current that flows in one direction. However, our homes and the entire systems are designed on alternating current in which the electrons or the current do not flow in one direction but periodically change the direction.
Alternating current is produced by generators when a metal coil is rotated in a magnetic field. The choice of alternating current has been made for quite a number of reasons, mainly because it is easy to transfer alternating current over long distances and is much cheaper as well.
Solar panels produce directional current which means that the current being produced by the solar cell cannot be used as is. Now, the main question arises, how can this directional current then be used to meet our electricity demands? This directional current needs to be converted into alternating current to be able to be used in our homes. For this purpose an inverter is used.
Most of the solar panel systems have been designed using central inverters, in which one inverter is collectively used for the entire solar panel system. With advancement in technology micro-inverters have been introduced which are designated for individual solar panels and thus make the system more efficient. With the use of micro-inverters a fault in one of the solar panels will not affect the working of the entire system; thus maximizing output and efficiency of the system.
The output of the inverter is alternating current which will be distributed to your home through a panel. This electricity will be the same as the electricity you were receiving from the utility and so you do not have to change any of your appliances to make it compatible with the solar panel system.
How does the solar panel system work at your home?
If you are planning to install a solar panel system at your home, then your home must have enough roof space to install the solar panels. The roof space in most houses is usually sufficient enough to be able to produce solar energy that can meet the house’s energy demand.
When sunlight falls on the panel, directional current is produced which travels to the inverter where it is converted into alternating electricity that can be used to power the house. Your house is now getting clean energy and you are not damaging the environment and causing air pollution. This will work wonderfully on sunny days; but you do not have sunny days throughout the year. Where will the electricity come for the nights?
After the solar panel system installation, your house will still remain connected to the area’s grid. This means that you now have two sources of electricity. This requires that you install a net metering system instead of the usual utility meter. Setting up the net metering system is an essential component of the solar panel system.
The solar panel system can have an additional storage system to store excess electricity produced and then be used at a later time. Software monitoring can also be included in the storage to monitor the power and manage power usage smartly. This way you will be able to save more on electricity and the bill also.
How to choose the Best Solar Panel System?
Choosing the best solar panel system on your own can be a difficult task. It is best to take help from the professionals. In order to avoid any scam and get the best possible solution, visit the AEDB website to know about the registered companies of Pakistan and then choose the company that can supply and install solar panel systems in your area.
Prices of the system vary with the size of the solar panel system. You yourself cannot judge the size needed for your home. You can contact any reliable company and then use their expertise to determine the suitable size for your house and the cost. You can get quotes for the same size from multiple companies and then go for the best price.
Solar panel systems are an expensive investment. Most people cannot pay the whole amount at a time. This is why most companies offer solar financing for the customer which enables the customers to use solar energy without purchasing the system. Usually an upfront amount is paid and the rest is payable through instalments agreed by the customers.
The companies also offer maintenance and repair services to the customers.
Your next step:
Solar energy is the most abundant resource and is readily available as well. Utilizing it for meeting the energy demands is the best option for the earth and the people as well. But solar panel systems are quite expensive and difficult to set up therefore, solar energy cannot be used effectively. However, research is being continuously done and great advancements have been made in developing the solar panel systems to be more efficient and affordable by the people. If technology continues to develop, there is great hope that soon the world will be free from energy crises and people will be able to enjoy free electricity.