The energy from the sun is a vast and inexhaustible resource. Every morning the sun bathes the earth with ample amount of energy required to fulfill the power needs of the entire world many times over. Solar energy is a clean alternative to fossil fuels, whose usage pollutes the environment and causes global warming as well. As the cleanest source of energy found in abundance, solar energy is all set to become the energy of the future.
How is solar energy converted?
The sun rays that touch the surface of the earth contain energy. When these rays touch an object, the energy gets transformed into heat but when the same rays hit a specific material like silicon, the energy gets transformed into electric current, which can be harnessed to produce electricity.
The most widely used method to harness solar power is silicon-made solar panels consisting of small clusters of PV (Photovoltaic) cells combined together. Light striking a silicon semiconductor causes electrons to flow, creating electricity. Solar power generating systems take advantage of this property to convert sunlight directly into electrical energy. Solar-powered photovoltaic (PV) panels convert the sun's rays into electricity by exciting electrons in silicon cells using the photons of light from the sun. This electricity can then be used to supply renewable energy to your home or business establishment.
Solar cells are constructed with two sides one being the positive and other being the negative (similar to how a magnet works) which together create an electric field. When light hits a solar cell, they strike electrons loose from their atoms and if conductors are attached to the positive and negative sides of a cell, it forms an electrical circuit. When electrons flow through such a circuit, they generate electricity. The more panels you set together, the more energy you can generate.
The electricity generated by the solar panels is in the form of DC (direct current) electricity, whereas most of our products require an AC (alternating current) electricity to run. Thus a solar inverter is used to convert the electricity from solar panels (DC) into power that can be used by the plugs in house for TV, computer, and other wired products (AC).
There are majorly three types of solar grids that you can install to get your home equipped with solar energy. All of these systems use solar panels and other components to generate electricity from sunlight and reach your home.
The three types of solar grids
On Grid: On Grid solar power system is directly connected to the traditional electric utility grid and to the home. This system allows the homeowners to get power seamlessly from either the home electric system or the utility grid. The major advantage in this type of system is the ability to balance the system production and home power requirements. When the system is producing more power than required for home consumption the excess can be sold back to the utility in a practice known as net metering. In net metering when the system is not producing sufficient power, the home can draw power from the utility grid which was previously sent back due to excess generation.
On Grid systems offer the lowest cost for residential solar electric system, due to fewer required components.
Off Grid: An Off Grid system is not connected with the traditional electric power grid. Due to the non-connectivity to the utility grid, batteries become an essential part of the system to balance in case the power is generated in excess or there is an excess demand. When the solar system is under-producing and even the batteries are discharged an electric generator can be added to the system to protect against insufficient power supply.
Grid Tie with Battery Backup: Grid Tie with Battery Backup system offers advantages of both On Grid system and an Off Grid system. Which means, when utility grid power is available, the system works just like a standard on grid system and sends excess power back to the grid. But unlike a standard system, when the utility power supply is not there, the battery backup allows the solar array to continue to supply the home with power during the day, and the batteries can supply select circuits within the home during the night. Once the utility grid starts up again the system automatically switches back to normal operation.
While Grid Tie with Battery Backup system offers more flexibility, still it has certain disadvantages. Continuous charging and discharging batteries reduces the overall efficiency of the system. Designing this system is also complex and expensive as compared to the other systems.
Works at night too…
At the night time, solar panels are not that active in producing power, but still the appliances at your home get power to work. Can you guess how?
Net-metering is what can be used in this scenario. To utilize the solar energy at the night time, your home is connected with a utility grid which acts as a reservoir for excess power generated in the daytime. During the daytime, the excess power generated is sent back into the common electric grid shared by all. And during the night when your system is not able to produce enough power for your appliances, you can draw power back from the grid and utilize it as per your requirement.
In some areas where there is lack of efficient power grid battery backup is also a good choice. Power is generated during the day and then banked in the batteries to be used when needed.
Solar Energy - The ‘sunny’ path ahead
Solar energy is the cleanest and unlimited source of energy. The solar sector is fast expanding its reach everywhere, in India and overseas. The energy which was looked upon as energy for the future is now actually being utilized today in several forms. With the government’s impetus to spur the growth of the solar sector, recent investments, ongoing research and development going on in the solar sector, the day is not far when we’ll have panels that can generate seamless electricity 24/7.