The evolution of energy generation continued with the evolution of mankind. The solar energy is harnessed by humans since ancient times using a range of ever-evolving technologies as well as practices. Solar energy technologies include solar heating, solar photovoltaic (generation of electrical energy), solar thermal electricity and solar architecture, which can make considerable contributions to solving some of the most daunting problems the world now faces, such as energy security, pollution control and global warming. Beside this source of energy is renewable.
Among many alternative non-conventional and renewable energy sources, the three and technically feasible options are Tidal, Wind and Solar energies. Nuclear energy is yet another option for very large scale electrical power generation. While Tidal and Wind energy generation is possible only at limited locations due to dependence on availability of Tidal waves and good velocity Winds, the Nuclear and Solar energy generation do not have such locational constraints. Tidal wave energy is yet to reach its commercially viable position.
The advantage of Wind and Solar energy generation is non-requirement of water either for process or for cooling, as a result these can be installed at any arid place. Beside these are not dangerous like Nuclear power plant where radiation leakage problem may occur due to some acts of God like earth quake, floods or Tsunami. The only constrain is the requirement of large space for large scale electrical energy production. India is blessed with many such places like Rann of Kachchh in Gujarat for example, where although water is not available, the vast non agricultural land with good wind velocities as well as good solar radiation is available. Here already many wind farms as well as solar farms are in operation for large scale electrical energy generation. Due to very high capital cost, the wind turbines or wind mills are installed in the range of more than 250 KW capacities. A large number of such wind mills are located at one place and known as wind farms, where electrical energy in MW range is generated and wheeled through the existing net work of Discoms or Transcoms. Although the concept of micro wind mills is also being debated, but so far wind farms of MW range are commercially viable and are in operation worldwide.
The greatest advantage of solar power generation is its range. It can be from few watts to mega watt, depending upon the requirement. Due to this the solar energy can be generated and used for the individual requirement and can be specifically designed. Also in such case there is no need for transmission and distribution. A few KW solar power plants can be roof top mounted and the electrical energy so generated can be used for the particular application. Some of such examples are solar traffic signal lights, solar street lights, and solar water pumps. Solar lights that charge during the day and light up at dusk are common sights along walkways, traffic signals, signage boards, village road lighting to name a few applications. Solar-charged lanterns have become popular in developing countries where they provide a safer and cheaper alternative to kerosene lamps. In case of use of solar energy to generate heat are solar cookers to cook food, solar water heaters. This is yet another advantage that the same solar energy can be used to generate electricity as well as heat. Unlike other non-conventional energy sources such as wind, tidal and nuclear plants, it does not need skilled men power for its upkeep and maintenance and are easier to install. Also the gestation period for such solar power plants is much less. It is pollution free, safe and clean source of energy. Solar generators can be the best method of distributed generation. The only constraint is the requirement of large space per KW of electrical power. But other advantages like non-dependence on water, safety, ease of operation and maintenance and flexibility of the rating depending upon the power requirement, fund availability and the space available outweigh this constraint. Although the manufacturing of solar panels is highly techno sophisticated, the users do not have to face many problems. So the solar energy has vast potential for development as well as usage.
Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels for generation of electrical energy and solar thermal collectors to generate heat to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air. Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies.
In 2011, the International Energy Agency said that “the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered as learning investments; they must be wisely spent and need to be widely shared”.
The Earth receives a lot of incoming solar radiation approximately 30% of which is reflected back to space while the rest is absorbed by clouds, oceans and land masses. It is estimated that the amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth’s non-renewable resources of coal, oil, natural gas, and mined uranium combined. On a surface on the Earth’s orbit, normal to the sun, solar radiation that hits the earth is estimated at the rate of 1,366 Watt Per Meter Square. This is known as solar constant. Solar energy can be harnessed in different levels around the world. Depending on a geographical location, the place closer to the equator, the more solar energy is available. Solar energy refers primarily to the use of solar radiation for practical ends.
The photocell or photovoltaic cell (PV), is a device that converts light energy into electric current using the light sensitive substances such as Selenium and Silicon which convert incidental light energy into electric energy. India is lucky to have a huge potential for tapping the abundant, free, non-polluting and renewable energy of sun. The Indian Renewable Energy Development Agency is busy creating a programme to facilitate the use of solar energy in over one million homes in India in the next few years. Solar Energy is the energy received from the sun that sustains life on earth. For many decades solar energy has been considered as a huge source of energy and also an economical source of energy because it’s free availability. However, it is only now after years of research that the technology has made it possible to harness solar energy. The most basic process of harnessing the solar energy is pictorially illustrated as under.
(Reference: Wikipedia). A photo panel receives solar light energy and converts the same into electrical energy. A device called charge controller regulates the flow of electrical current to a storage battery, which stores the electrical energy so generated in chemical forms. The battery storage will be required to supply power during night time and during cloudy or stormy conditions. Now this electrical energy can be used to operate electrical devices. Two most popular applications of solar energy for illumination is the Solar powered street lights and Solar powered Lanterns are depicted below.
Typical Solar Street Light & Typical Solar Lantem
Solar Energy Facts: Solar Energy is already being successfully used in residential and industrial settings for cooking, heating, cooling, lighting, space technology, and for communications among other uses. In fact, fossil fuels are also a form of solar energy stored in organic matter. With fossil fuels making major impact on the environment and raising issues of pollution and global warming, solar energy has gained its importance in industries and homes. While the reserves of fossil fuels are restricted, available at selected places, available at cost and liable to be exhausted, there are no limitations to the availability of solar energy. With improvement in solar energy technology and the increase in prices of fossil fuel, solar energy is gradually becoming more and more affordable source of power generation as well as heat source. In addition, there is additional cost in the form of importation and transportation, required for oil, coal and gas. In the last few years, the cost of manufacturing of photovoltaic cells has gone down considerably and the percentages of government subsidies have gone up.
This means that every year, it is becoming more and more affordable to use Solar Energy. It is estimated that the amount of energy released by a single Kilo Watt of solar energy unit is equivalent to burning as much as 76 Kg of coal that releases over 35 Kg of carbon dioxide. As per energy industry giant, Shell more than 50% of the global energy in 2040 is going to be in the form of renewable energy. And, the demand for Solar Energy has grown due to policies in green pricing from utilities and government rebate programs. The demand has also grown due to the interest of households to get electricity from renewable, non-polluting and clean source. Vacation homes or holiday homes that don’t have access to the grid can utilize Solar Energy in a more cost-effective manner as compared to relying on the grid for running wires to the remote location. People living in remote areas having sufficient sunlight can get reliable power in the form of solar energy. The basic components required in the solar power system consists of a solar panel, battery for storing all the energy gathered during daytime, a regulator and essential switches and wiring. These types of systems are commonly known as Solar Home Systems (SHS).
Solar Energy Cost: When you want to install Solar Energy system at home, you would require it to be sufficient for meeting all electricity requirements in home for a day plus it should generate enough power to store for 3 to 5 days for contingency purpose. Such a system would keep supplying power and getting charged when the days are sunny. During rain or winters it would be able to keep backup charge for a couple of days until the sun emerges. This means that such a solar power system is going to supply you a regular flow of electricity. Solar panels are one of the most important factors in the generation of Solar Energy. On an average, 1 sq ft of Solar Panel generates 10.6 Watts of power. And, the cost of 1 sq ft of Solar Panel is approximately Rs 4,500. 10.6 Watt of power is sufficient to light a 10’*10’*10’ room. So, if you want to power appliances like television, refrigerator and computer, you would need more solar panels, and it may not be economically viable.
Advantages of Solar Energy: Solar Energy has more advantages than you can point out the disadvantages. Once the initial cost of installation is met, the electricity generated by solar panels is free of cost. So it provides hedge against. The government offers lots of rebates and incentives to cover the initial cost. Another good thing about solar power is, the cost of the technology is decreasing almost every few months and the efficiency is improving significantly. Today, we can find different types of solar solutions that are more convenient to install. Solar Energy is a renewable and clean source of energy and there is no transmission cost as well as losses. This is because the energy would be produced and consumed at the same place. Depending upon the budget, we can get all or a part of our electricity requirements fulfilled by solar energy. When batteries are used in the system to store electricity we can become entirely independent of the grid. This also means that no power failures and we would be able to enjoy seamless supply of electricity.
Disadvantages of Solar Energy: Even though Solar Energy has several disadvantages, they are not major in degree and the benefits of this renewable source of energy far outweigh them. The initial cost of the installation and equipment is high. When you compare fossil fuel technology with solar power technology, the former will seem to be far more affordable for large scale power generation. Even though Solar Energy is being used at an increasing rate, the initial costs don’t encourage the maximum users to switch to this renewable source of energy.
If there is shortage of space for installing solar panels, you would not be able to generate sufficient amount of Solar Energy required to meet your electricity requirements. Due to this reason, the solar energy use is restricted to the applications which are not power intensive such as lighting and direct heating. The use of solar energy to generate power on commercial scale is still not in vogue, although power plants in the range of few megawatts are set up recently. With the availability of high luminous efficient light sources such as Compact Fluorescent Lamps (CFL) and Light Emitting Diodes (LED), the use of solar energy for illumination has gained momentum. This has resulted in wide spread use of solar street lights, solar lantern etc. Considering all these factors, it appears that solar energy may become the formidable source of energy requirement in households as well as in industries, both in the future and in the next few years. It is only a matter of time before Solar Energy technology becomes easily affordable to make this untapped and unending source of energy a common phenomenon in every household.
Synopsis
Sun is the universal source of energy. Its light is used by default during day time and heat is used for some application such as hot water and cooking. But the ability of photovoltaic plates to convert light energy into electrical energy and the storage of this electrical energy into storage battery and then using the electrical power so generated has led to a situation where solar energy is used even during night hours. India is blessed with a unique geographical location where sun is everyday shining on it. We can use this free form of energy to meet our most basic needs of illumination by harnessing it for illumination and leaving other highly capital intensive high end electrical energy needs for lavish applications such as Air Conditioning, Heating for cooking and refrigeration etc.
