Solar panels are devices that are designed to absorb sunlight as a source of energy for generating electricity. Also called as photovoltaics by some scientists, the panels are gradually becoming popular the world over as a result of increasing awareness about the benefits accorded by solar energy, both in terms of incremental cost savings as well as environmental benefits. Currently, solar panels are widely used across various industrial, commercial and domestic sectors. As for the future, their usage is only expected to increase, helped to a large extent by the emphasis put on the use of solar energy by environment activists and governments the world over.
Simply put, solar panels are a collection of solar cells, with their construction design based on the thought process that lots of smaller cells spread over a large area can work together to provide enough power to be useful. The panels are generally designed in such a way as to ensure maximum sunlight hits the cells, thus increasing overall efficiency of the panels. These are available in various dimensions and with different usage mechanisms, ranging from those used in homes to provide electricity to those used to power handheld agricultural sprayers.
Harnessing of solar energy:
As everyone would recall, solar energy is a renewable source of energy that has the ability to completely replace traditional energy sources. Apart from some logistical and locational issues, there is nothing that makes solar energy inferior or less usable to traditional energy sources in any form. People have harnessed solar energy for centuries. As early as the 7th century B.C., people used magnifying glasses for concentrating the light of the sun into beams so hot that they would cause wood to catch fire.
Modern harnessing of solar energy dates back to more than 100 years ago in France, when a scientist used heat from a solar collector to make steam to drive a steam engine. The research for optimal and practical harnessing of solar energy in all earnest began in the 20th century, with a landmark breakthrough coming in the form of an efficient solar boiler invented by charles greeley abot, an American astrophysicist, in 1936.
The solar water heating industry first gained prominence in Florida, united states around 1920's and by the start of second world war, it was being used by a lot of people across America. Apart from their use in heating, solar energy wasn't being fully utilized due to the fact that a majority of public and also government's across the world were insensitive towards it. Coming to the oil crisis of the 1970's precipitated by gulf countries and the worsening of international diplomatic relations, government's across the world had to wake up to the need of finding a replacement for oil. Solar power was the most obvious energy form to replace oil. This resulted in a massive emphasis being put by government's the world over to increase the usage of renewable energy sources.
Case for promoting the use of solar energy:
The below mentioned points promptly lay out the reasons for increasing the usage of solar energy.
The below mentioned points promptly lay out the reasons for increasing the usage of solar energy.
- It's a proven fact that half of the world's oil reserves will not last beyond 2040. Oil shortage will surely mean massive unrest amongst citizens across the world. Thus it is pertinent that usage of solar energy as a replacement for oil is emphasized.
- We all know what greenhouse gases have done to the ozone layer and as an extension to our environment. As a result of greenhouse gases, glaciers around the world are melting faster than ever before, strange weather patterns are being seen etc. The situation will keep turning more and more drastic if we do not find a way to replace traditional energy sources with other renewable ones like solar power
- Solar energy is comparatively much cheaper than fuel or coal energy. Although the initial cost is high, it provides benefits due to the fact that apart from the initial investment, no additional investment is needed for the continuous generation of electricity from solar panels
- This is a known fact that everyday the amount of solar light that hits our planet is enough to meet all our energy needs for a whole year. So why not utilize some of this energy.
- Solar energy is the ideal source of energy for people living in rural areas across the world, where it might be comparatively much costlier to provide power using traditional energy sources. Thankfully, governments across the world are concentrating on using solar power for meeting energy demands, a case in point being state governments of uttar pradesh and tamil nadu. These two states are selling solar panels to people living in rural areas at a subsidized rate. This should be encouraged and implemented to a much larger area.
Construction and working of solar panels:
- A slab of pure silicon is used to make a solar cell. The top of the slab is thinly diffused with an “n” do-pant such as phosphorous. As for the base of the slab, a small amount of “p” do-pant( which is generally boron) is diffused. The phosphorous has a negative charge and gives the wafer of silicon an excess amount of free electrons. As for the boron used, it is not charged but because of it's tendency to attract electrons, it gives the base of silicon a positive character
- When the n-type and p-type silicon meets, free electrons from n-type flow into the p-type silicon. This point of contact is called as the p-n junction.
- When the solar panels are placed in the sun, photons of light strike the electrons in the solar cells p-n junctions, energizing and knocking the cells free of atoms. Almost all photon electron collisions occur in the silicon base of the cells
- A conducting wire connects the solar panels to an electrical appliance such as light, battery etc. The conducting wire provides a path for the electrons to move away from each other. A noteworthy thing here is that the wire is connected from the p junction to the electrical; appliance and back to the n- junction, thus completing the required circuit to enable flow of electricity.
How efficient are modern solar panels at harnessing solar energy:
Solar panels generally convert around 15 percent of their available energy into electricity. It might seem less to the uninitiated but that's how solar panels work. Although advanced solar panels are already available that convert around 21.5 percent of their available energy into electricity. With constant innovation and design improvements facilitated by cutting edge research, the efficiency of solar panels is only expected to grow further in the coming years, with recent research at the imperial college, London showing efficiency of the solar cells can be improved further by studding the light receiving semiconductor surface with aluminum nano cylinders.
How the sun's energy is concentrated inside solar panels:
There are several different types of technologies that use mirrors or other reflecting surfaces to concentrate the sun's energy upto many times it's normal intensity.
- Parabolic troughs - These use long reflecting troughs that focuses the sunlight onto a pipe located at the focal line. A fluid circulating inside the pipe then collects energy and afterwards transfers it to a heat exchanger. The world's largest parabolic trough is located in the Mojave desert in California, united states.
- Power towers - These use a large field of rotating mirrors to track the sun and focus the sunlight onto a heat receiving panel on top of a tall tower. The fluid inside the panel then collects the heat and uses it to generate electricity
- Dish/ engine systems – These are like satellite dishes that concentrate sunlight and have an engine located at the focal point to generate electricity
- Concentrated solar power – The concentrated solar power technologies require an unhindered supply of continuous sun light, like that received in desert areas.
Applications of solar panels:
There are many application areas for solar panels ranging from in agriculture as a power source for irrigation to in infrastructure construction. A list containing some application areas of solar panels is mentioned below:
- Photovoltaic power stations
- Rooftop solar photovoltaic systems
- Standalone photovoltaic systems
- Solar planes
- Solar vehicles
- Solar pumped lasers
- Concentrated photovoltaics
Essentials to check before installing solar panels:
- The topmost requirement for any place where solar panels are being installed is uninterrupted access to sunlight during day time hours.This makes solar panels not so feasible for places were the presence of sunlight cannot be guaranteed such as countries nearby north pole and south pole or countries with excess rainfall etc.
- Before installing solar panels, always ensure that your site or building is free from shading by trees, nearby buildings etc
- Another fact that needs to be checked is that is if your roof or site is large enough so as to optimally contain solar panel system
- If your roof is older and needs to be replaced soon, then only install solar panels after replacing the roof. This will eliminate the additional logistical problem of uninstalling and installing the solar panel again, as a result also saving costs
Concept solar panels that might become a possibility in the future:
Scientists and energy conservationists have long been fantasizing about the design and efficiency of future solar panels. Some see solar panels as all pervading, being used in all aspects of our lives, while some are comparatively less optimistic. It should be accepted that a future all encompassing usage of solar panels is beyond the realms of possibility as for now, yet compared to today, the scope of their usage is much larger in the future.
Some of the possible future usage areas of solar panels are:
- Cars and other modes of transport only powered by solar energy, with solar panels installed on their roof - to achieve this, we would first have to create much more efficient solar panels that convert more than 21.5 percent ( the figure for the most efficient solar panels as of today) of their stored energy into electricity
- A solar panel road that is able to support the force of any vehicle driving across it ( a 70 meter cycle path with the same mechanism is currently being used in Amsterdam)
- Solar panels that can coat shingles, skylights, windows etc
- Solar powered electronic charging spots in public places
- Solar energy based power plants that convert sunlight into electricity and supply it to homes, offices etc., thus completely replacing current power plant distribution systems.
