Why do we worry about energy security if energy can neither be created nor be destroyed?
It is true that energy neither can be created nor can be destroyed. As we also know that the energy comes from a different form and one form of energy can be converted to another form, at present, we do not have the technology to us to use all form of energy and to convert one form of energy to the desired form. For examples,- If we drop a plate from a height, the potential energy of the plate is mostly converted to sound energy.
- The same is not reversible ( i.e the sound energy to potential energy), at presently available technology.
- If we light a candle, the chemical energy of Wax is converted to heat energy and light energy on burning.
- The same is not reversible ( i.e the heat and light energy to chemical energy), at presently available technology.
We have limited sources and forms of energy to use. Once we consumed can not be used or reverse again.
What is the good Source of energy?
A good source of energy has the following features.- Would do a large amount of work per unit volume or mass.
- be easily accessible.
- would be easy to stores and transport.
- Most importantly, be economical.
What are fossil fuels?
The following are fossil fuels:- Woods:
- Wood was the most common sources of heat energy
- Coals:
- The industrial revolution was succeeded because of the proper exploitation of coal as the source of energy for machines, transportation, energy generation, and communications.
- Petroleum:
- Mostly use in transportation.
What are the limitations of Fossil fuels?
- Non-renewable:
- Fossil fuels are non-renewable in nature, if we consume it at an alarming rate it will end.
- Create Air pollution:
- Burning fossil fuels emits harmful gases like Co2, CO, Methane, Ozone, etc.
- Acid rain:
- Oxides of Carbon, Nitrogen, and Sulphur led to acid rain
- Create a Green House Gas(GHG) effect or Global Warming:
- Co2, Methane.
Air pollution and GHG emission can be reduced by :
- Increasing the efficiency of the combustion process
- Using the various technologies to reduce the escape of harmful gases and Ashes into the environment.
How electricity is generated?
- It is generated by Dynamo. Dynamo converts mechanical energy( i.e moving Fan) to electrical energy.
What are the conventional sources of energy?
- Thermal Power Plant
- Hydro Power Plant
- Bio-mass
- Bio-gas
- Charcoal
- Wind energy
Thermal Power Plant
The following steps used in thermal power plants to generate electricity. |
| Thermal Power Plant |
Hydro Power Plants
The kinetic energy of flowing water or potential energy of water at height is converted to electricity.What are the limitations of the construction of the big dam?
- It can be made in a limited number of places, preferably in hilly terrains.
- Large areas of agricultural land and human habitation get submerged.
- Large Ecosystem destroyed when it submerged underwater.
- Submerged vegetation rots underwater emit a large amount of Methane which is Green House Gas. Renukoot-Singrauli in Uttar Pradesh is an example of Methane Hotspot emission in India.
Bio-mass
- These fuel sources are plants and animal products.
- The use of Cow-dung Cakes is an example of biomass.
Limitation:
- It does not produce much heat on burning
- Produces lots of smoke
Bio Gas
When ( cow dung, residue after harvesting, vegetable waste, sewage) decomposed in the absence of oxygen, bio-gases are produced.
Charcoal
When wood is burned in the limited or no supply of Oxygen.Benefits of Charcoal:
- Charcoal burns without flames
- Comparatively smokeless and has higher heat generation efficiency.
Wind Energy
Air movement generates and causes winds to blow by unequal heating of landmass and water bodies by solar radiation- Electricity generated by the movement of the turbine through windmills.
What is wind farming?
- The number of windmills is erected over large areas that are known as wind farming.
- Denmark generates 25 % of own energy requirement from Wind energy.
- However, India comes 4th in total installed wind capacity after China(1st), USA(2nd), and Germany(3rd).
- It is environmental friendly
- Efficient source of renewable energy
- No recurring expense for the production of electricity
What are the limitations or drawbacks of wind energy generation?
- It can be established in only those paces where winds blow for the greater part of the years.
- To maintain the required speed of the turbine, wind speeds should be higher than the 15 KM/hour.
- Need backup facilities like storage cells to take care of energy needs during a period where there is no wind.
- Large areas needed for a commercial establishment. For example, 2 hectares of land is needed for 1 MW generation of electricity
- The initial cost is very high for the establishment.
- High levels of maintenance needed as towers and blades are exposed to rains, sun heat, storms, and cyclones.
What are the non-conventional sources of energy?
- Solar energy
- Tidal energy
- Wave Energy
- Ocean Thermal Energy
- Geo-Thermal Energy
- Nuclear Energy
Solar Energy
- For nearly 5 billion years, Sun has been radiating an enormous amount of energy and it will continue to give energy for 5 billion years more.
- In our earth atmosphere, only a small fraction of solar energy reaches on it.
- Out of this, 50 % of sunlight is absorbed by the atmosphere while passing through it.
- Black surface absorbed more heat compared to the white or reflecting surface under identical conditions.
Electricity is generated from solar in two ways:
- Solar thermal
- Photovoltaic cell
What are the advantages of solar energy?
- It has no moving part as wind energy has.
- require little maintenance
- work quite satisfactory
- they can be set up in sparsely or remote areas.
What are the limitations of solar energy?
- Availability of special grade Silicon for making solar cell is limited
- Manufacturing cost is very expensive
- Silver used for interconnection of cell the panel further adds the cost of manufacturing
- Required battery for storage when solar light is not available
- Over time, the performance of solar panel get depleted
- The mishandling of E-waste generated by solar panel creates environmental problems.
Tidal Energy.
As the level of water in sea rises and falls due to the gravitational pull of mainly Moon on spinning earth. This event is called high and love tides. The difference in seal level gives us tidal energy. The turbine uses to convert tidal energy into electricity.Wave energy:
Kinetic energy possessed by a huge wave near the seashore can be traped to generate energy via the turbine.Ocean Thermal Energy:
- As the water at the surface of the sea or ocean is heated by the Sun while water in the deeper section is relatively cold.
- Ocean Thermal energy is generated by the temperature difference of ocean surface and ocean depth.
- This energy can operate if the temperature difference in 2 KM depth > 20-degree centigrade
- Warm surface water is used to boil a volatile liquid like Ammonia.
- The vapor of a liquid is then used to run the turbine of a generator
- The cold water from the depth of the ocean is pumped up and used to condense the vapor again to liquid.
Geo-Thermal Energy:
- Due to geological changes, molten rocks formed in the deeper hot region of the earth crust pushed upward and trapped in certain regions called "hot spots".
- The stream is generated when underground water comes with contact with the "hot spots"
- Stream trapped in rocks is routed through a pipe to run the turbine to generate the electricity.
What is the advantage and disadvantage of geothermal energy?
- The cost of production is cheap but very few commercially viable sites are available.
Nuclear Energy:
- Nuclear energy is generated through Nuclear fission.
- The nucleus of heavy atoms such as Uranium, Plutonium, Thorium bombarded with low energy neutron. As a result, a tremendous amount of energy is released.
- The fission of an atom of uranium = 10 million times of energy produces as compared to the atom of carbon from coal.
- Released energy can be used to produce stream and further generate energy.
What are the limitations of Nuclear energy?
- Mishandling of the storage fule, disposal of spent or used fule can be very hazardous for the environment, and human loss.
- Uranium still decaying into harmful sub atom particles.
- Improper nuclear waste disposal leads to Environment contamination
- Risk of accidental leakage of nuclear radiation
- The high cost of installation of plants
- Limited availability of nuclear fuel such as Uranium.
Notes: Nuclear fusion reaction are the sources of energy in the Sun and other stars
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