Non-Conventional Sources of Energy sources

Introduction

Energy is present in various forms within and outside the organisms in an active or passive form. 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 sources that we regualrly use them. The conventional sources of energy are the natural resources available in a limited quantity. Conventional sources are usually non-renewable in nature, for example, petroleum and coal. On the other hand, the non-conventional sources are the renewable sources found in abundance. In this section, we will focus on the most common non-conventional sources of energy including solar energy, geothermal energy wind energy and biogas.

 

Table of Contents

1. Introduction

2. Solar energy

   2.1 Advantages and disadvantages of solar energy

   2.2 Solar devices

      2.2.1 Box Type Solar Cooker

      2.2.2 Solar cells

      2.2.3 Solar panel

3. Wind energy

     3.1 Mechanism of wind fans

     3.2 Advantages and disadvantages of wind energy

4. Geothermal Energy

5. Tidal Energy

6. Nuclear Energy

 

Solar energy

It is one of the excellent sources of renewable energy becasue solar energy is available forever except during the bad climate. It is, in fact, the most under-utilized source as the sunshine is not available round the clock. Sunshine varies between seasons, so the energy that reaches the earth on a daily basis varies between 4 to 7 kWh/m2. The solar energy that reaches per unit of the earth is called solar Constant. India is mostly tropical in its climate hence there are lots of opportunities to generate solar energy. Solar energy can be converted into various other forms. One such commonly convertible form is the electric energy. The photovoltaic technology adopted in the solar plates will convert the sunlight directly into electricity . Solar energy can be used in small scale settings and the domestic environments. Solar energy emitted by the sun is trapped through solar plates, panels and the plants. The largest solar plant in India is located at Madhapur, near Bhuj 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

  1. It is a renewable source of energy availabl free of cost
  2. It does not harm the environment 
  3. Intial investment for the equipment will suffice and it doesn't require a high maintenance cost 

Disadvantages of solar energy

  1. Cannot be used during rainy days and at night.
  2. The direction of the reflector has to be kept changing from time to time according to the direction of the sun.
  3. Seasonal variation as a result of winter and rainy seasons may interrupt the production of solar energy. 

 

Solar devices

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 quickly than any other. 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 devices that convert solar energy into electricity. They generate a voltage of 0.5 – 1 volt with 0.7 Wats of electricity. It needs some maintenance but it doesn’t need any focusing device. It can be set up even in the most remote areas without any dditional equipment. Probably it’s one of the best environmentally – friendly modes of electricity production with no chance to cause pollution. Solar cells are used in calculators, watches, artificial satellites and space probes. It is also used in radio or wireless transmission system.

Disadvantage of Solar Cells

  1. It requires a high initial cost to set up when compared to other electrical devices.

  2.  It needs sunshine and in the night time it may not produce energy so, energy must be stored for night usage.

  3. Its efficiency is low for the high-end devices demanding more energy to run.

  4.  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 energy

Wind fans work on the principle that, irregular heating of landmass and water bodies creates air movement result in the forcible wind blow. It is a kinetic energy source and useful in a wide variety of settings.  In the olden days, wind energy was used to carry out mechanical works for example, the rotatory motion of windmill was used to lift water from a well through a water-lifting pump. In the modern days, the wind energy is turning out to be a primary source of energy especially in hilly terrains with high 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.

Advantages

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.

 

Disadvantages

 1. Wind energy farms suit only in 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.

 

Geothermal Energy

Earth`s core is a great source of heat energy. It is found that heat has been radiating from the centre of the earth from 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 has 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 but it is not available everywhere. Due to geological changes, when the earth’s crust is pushed upwards this lead to 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

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 Energy

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.

 





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