Energy is present in various forms within and outside the organisms in various forms. What we see around us is the expression of itself as energy, for instance, the energy in the sunlight is expressed as heat, brightness and shiny. Based on the source of energy, the resources are divided into conventional and non-conventional. Conventional sources are the traditionally used sources on a day to day basis. The conventional sources of energy are the natural resources available in a limited quantity. They are usually non-renewable and quickly exhaustible in nature, for example, petroleum and coal. On the other hand, the non-conventional sources are usually the renewable and inexhaustible sources found affluently. In this section, we will focus on the most common non-conventional sources of energy including solar energy, geothermal energy wind energy and biogas.
It is one of the excellent sources of renewable energy becasue solar energy is available forever, nonetheless, it is limited to the daytime where sunshine is rich. It is, in fact, the most underutilized source just because of the non-availability of sunshine round the clock. Sunshine varies between seasons, thus the energy that reaches the earth on a daily basis varies between 4 to 7 kWh/m2. The amount of solar energy that reaches per-unit area of the earth is called solar Constant. Solar constant varies between each geographic areas. India is mostly tropical in its climate hence the available opportunities to trap the sunlight is easy. Moreover, the technology used for generating solar power is not very intricate.
Mechanism of solar energy
Solar energy can be converted into various other forms mainly into the electrical energy. The photovoltaic technology adopted in the solar plates will convert the sunlight directly into electricity. But the drawback of the solar energy is that it can be used in small scale domestic settings as it may not support high voltage input devices. Solar energy emitted by the sun is trapped through solar plates, panels and the bigger solar plants. The largest solar plant in India is located at Madhapur, near Bhuj Solar energy, however, many new plants are underway.
Uses of solar energy
Energy generated from the sun can be used for solar cookers, solar water heaters, bikes and cars, solar cell panels, etc. However, solar energy is not always the right option becasue of the few disadvantages. The following table denotes the advantages and disadvantages of using solar energy.
Advantages of solar energy
- It is a renewable source of energy available free of cost
- It does not harm the environment
- It doesn't require recurring expenses as it doesn't require a high maintenance cost
Disadvantages of solar energy
- Solar energy cannot be used during rainy days and at night.
- The direction of the reflector has to be manually adjusted from time to time according to the direction of the sun.
- The solar energy depends upon the seasonal variation. Summer is the best time as sunlight is rich, whereas the rainy season is not very productive.
1. Box Type Solar Cooker
It is a box made up of insulating wood material. The inner walls are painted with black colour as the black absorbs the heat faster than any other colour. A plane mirror is used as a reflector to increase the number of infrared radiations falling on the box. A thin glass sheet is used as a lid to cover the box that can minimize the loss of heat. In other words, it is an artificial greenhouse effect that enables us to retain a lot of heat. The cost of making such a cooker is very less and the food never gets burnt when if the heat from the bottom is excess. Box type solar cooker help in keeping the food hot for a longer duration.
2. Solar cells
Solar cells are the smaller devices which can convert solar energy into electricity. They generate about 0.5 – 1 volt with 0.7 Wats of electricity. It requires some maintenance cost but it doesn’t need any focusing device like other devices. It can be set up even in the most remote areas without supplementary equipment. Probably it’s one of the best environmentally – friendly modes of electricity production as it is highly environment-friendly. Solar cells are commonly used in calculators, watches, artificial satellites and space probes.Furthermore, it is used in a radio or wireless transmission system.
Disadvantage of Solar Cells
It requires a high initial cost to set up when compared to other electrical devices.
It needs sunshine and in the night time it may not produce energy so, energy must be stored for night usage.
Its efficiency is low for the high-end devices demanding more energy to run.
It’s not highly effective during the rainy season.
3. Solar panel
A large number of Solar Cells connected to each other in an arrangement is called a solar panel (see picture below). It is made up of Silicon and the interconnection is of silver.
Wind fans work on the principle that, irregular heating of landmass and water bodies generates a free air movement that can be converted into mechanical energy with the help of fans. The fans in the wind energy are just like the turbines used in the hydroelectric power. Wind energy is a kinetic energy source that can be useful in a wide variety of settings. In the olden days, wind energy was used to carry out mechanical works such as the rotatory windmill to lift water from a well. In the modern days, the wind energy is slowly gaining its traction hence it is turning out to be the primary source of energy especially in hilly terrains with the highest wind flow. It is almost similar to a large electric fan being built in a high altitude region.
Mechanism of wind fans
Wind fans are the least economical but ecofriendly. To generate a minimum amount of energy, the rotatory motion produced by the wind will move the turbine of the electric generator. The electric generator will store the energy produced during turbine movement. It is not suitable for commercial purposes. But as an alternative, many windmills are connected together to form a wind energy farm. The combined energy of many fans will be put together to get electricity on a commercial scale.
1. It’s one of the most environment-friendly and also an efficient source of renewable energy.
2. Once installed, it won’t require high recurring expenses for maintenance.
3. It doesn’t need raw materials like in the case of hydroelectric plant or biogas plant.
1. Wind energy farms suit only to those places with forceful air movement for the most part of the year. The wind speed must be minimum 15 km/h to maintain the required speed of the turbine
2. There need to be some back-up facilities (like storage cells) to take care of the energy needs in the absence of wind.
3. A lot of space is required to build a wind farm. To generate 1 MW energy, the area of the farm must be at least 2 hectares.
4. Initial investment is quite high. If the blades of fans get exposed to rain, sun, storm, and cyclone, they need a lot of attention and maintenance.
Earth`s core is a great source of heat energy. It is observed that heat has been radiating from the centre of the earth from the past 4.5 billion years. At the depth of 6437.4 km, the centre of the earth generates the same amount of energy as that of the sun's surface. The earth`s crust can generate 9932°F (5,500°C) of heat energy. Earth holds many layers but the crust produces a lot of energy as a result of an excess of heat found in the liquid form -lava. The heated lava can be used to generate energy from the inner layers of the earth. Geothermal energy is a pollution-free source of energy, nevertheless, it is not available everywhere.
Mechanism of geothermal energy
Due to geological changes, the earth’s crust is pushed upwards. The forceful upward push can form some special areas called hot spots. When underground water comes in contact with the hot spot, steam is generated. Sometimes hot water from that region finds outlets at the surface. Such outlets are known as hot springs. The steam trapped in rocks is routed through a pipe to a turbine and used to generate electricity.
Tidal energy is a limitless and renewable source. For producing the tidal energy, dams are built close to estuaries that pours the inward and outward water currents and surges. Subsequently, the water is allowed to forcibly fall on the turbines. The forceful movement of turbines generate electricity. The tidal surge has to be a minimum of seven meters for cost-effective performance.
Nuclear fission and nuclear fusion helps in the generation of nuclear energy. Fission involves the splitting of a heavy nucleus of a radioactive atom. Nuclear fusion occurs when 2 or more heavy nuclei are combined to release a large amount of energy. Nuclear fusion and fission can generate a lot of energy as this is a high-intensity activity but it has many harms on life and the environment. One of the major hazards of nuclear power generation is that they directly enter the cells and cause damage to genetic material. It is highly risky to store and dispose of this form. The radiation emitted by radioactive materials like uranium can cause years of loss. On the other hand, the high cost of installation of a nuclear power plant, high risk of environmental contamination and limited availability of uranium make large-scale use of nuclear energy difficult. In history, there were many accidents due to nuclear energy, one of which is the Chernobyl accident. Even today the effects are visible. Hiroshima and Nagasaki's attack by Americans is another example that supports the fact that nuclear energy is highly potent.