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Electrochemical Machining (ECM) Principles

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Electrochemical Machining (ECM) is based upon Faraday's law of electrolysis. Faraday's law states that the the mass of a metal altered by the electrode is proportional to the quantity of electrical charges transferred to that electrode.
  • In ECM the removal of metal is controlled by the anodic dissolution in the electrolyte. 
In ECM -
  •  The workpiece acts as the anode
  • The tool act as cathode.
  • The electrodes should be placed closely with a gap of about 0.5 mm .
  • The anodes and cathodes should be immersed into electrolyte. (Here Sodium Chloride)
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Schematic illustration of the electrochemical-machining (ECM) process

Electrochemical Machining (ECM)

The main principles of ECM are as follows - 

  • A potential difference is maintained between the electrodes as a result ions existing in the electrolytes migrate towards the electrodes. 
  • Conventionally positively charged ions are attracted towards the cathode and negative ions are attached towards to the anode. And thus flow of current is initiated in the electrolyte. 
  • The set-up is kept stationary and tool is fed linearly. 
  • The desired amount of metal is removed because of ion migration towards the tool. 
  • For keeping the tool safe from damage a continuous supply of electrolyte is ensured by pumping it at high pressure (15kg/cm2). 
  • In this process the temperature generated is very low and no spark is produced and thus there isn't any scope of metallurgical changes in the job. 
  • When electricity is supplied to the metallic ions of the w/p is pulled out. The positive ions of the metal reacts with the negative ions present on the electrolytic solution and hydroxides of metal and other components. This hydroxides are precipitated and washed away by the electrolytic solutions.  
  • In Electrochemical Machining the tool and workpiece doesn't come in direct contact with each other so negligible wear and tear is observed. 
  • Metal removal rate is high and voltage supplied is very low. 
  • The metallic workpiece is not damaged due to thermal stresses. 
  • Dimensions up to 0.05 mm can easily machined . 

Examples of parts made by ECM 

Electrochemical Machining (ECM) Principles

Different parts made by electrochemical machining.  (a) Turbine blade material :  nickel alloy (b) Thin slots on a 4340-steel roller-bearing cage.  (c) Integral airfoils on a compressor disk.

 Electrochemical Grinding  (ECG) Principles  

electrochemical machining and electrochemical grinding


(a) Schematic illustration of the electrochemical-grinding process.  (b) Thin slot produced on a round
nickel-alloy tube by this process.

        Functions of Electrolyte
  •           The current is carried between the tool and the w/p through electrolyte.
  •           The produced heat is dissipated by the liquid electrolytic solution.
  •           The product of machining is removed by the solution.               
  •            It keeps the reactions continuous by supplying the elements necessary for the reaction.  

What Should be The Criteria of Selecting Electrolyte in Electrochemical Machining  (ECM) and Grinding (ECG)


The selection of the electrolyte should be done by considering the following matters - 
·         Required Machining rate 
·         Required Dimensional Accuracy 
·         Surface Texture and Integrity  

            
      The properties of Electrolytes 

  •            High Electrical Conductivity 
  •            High Current Efficiency for machining 
  •            Good Surface finish and integrity is necessary
  •            Composition of the electrolyte and structure of the material controls the final surface texture. 

 Flow Arrangement of the Electrolyte in  ECM / ECG 

       Perfect electrolyte flow across the machining tool is mandatory for proper machining.
      cavitation is likely to be occurred in the tool so proper care is necessary to keep the 
      tool in shape. Tool design must ensure the uniform flow of electrolytic solution in all
      the machining areas. Optimum flow of the electrolyte is desired because excessive
      flow can cause erosion of the tool. 
      
     Mainly two types of flows are used –
     1.     Divergent flow
     2.     Convergent flow

     Convergent flow provides a smoother flow of electrolytes. At first the electrolyte has to pass a
     chamber known as ‘dam’. The dam is used to pressurize the are outside  the working tool. 

   Advantages of convergent flow system.  
  
  •         Improved Surface finish 
  •         Improved Uniform and predictable side over cut as well as front machining gap. 
  •         Less prone to arcing. 
  •         Clean operating environment 
  •         Stray currents make it possible to eliminated unwanted machining.  
But it is also to be mentioned that machining in convergent flow is much expensive than divergent flow. 

Advantages of Electrochemical Machining (ECM)

  1. Accurate Machining 
  2. No direct contact between tool and job. 
  3. Negligible wear and tear of the tool. 
  4. Environment friendly 
  5. no thermal or mechanical stress is induced on the tool.
  6. There is no contact between worpiece and the tool so its is possible to machine non-rigid and open w/p. 
  7. Jobs with complex geometric shapes can be machined with ease accurately and repeatedly. 
  8. ECM is a time saver when compared to conventional machining. 
  9. During drilling several holes can be done at once.  
  10. Deburring can be done in hard to access areas. 
  11. Fragile and brittle materials which are prone to damage can be machined easily in ECM without cracking or breaking. 
  12. Surface finish up to 25 μ in can be achieved. 

Disadvantages of Electrochemical Machining (ECM)

  1. Sometimes this process is costly because the equipments are expensive. 
  2. Continuous supply of electrolytic solution is mandatory. 
  3. Steady voltage or potential difference should be maintained. 
  4. Rigid fixturing is required to withstood the high flow rate of electrolytes. 
  5. Designing the tool is arduous because it must be insulated to maintain the perfect conducting paths towards the workpiece. 
  6. Corrosion free material is needed for the structure and the electrolyte handling unit. 
  7. If hydrogen is liberated at the tool surface then it is possible to suffer from hydrogen-embitterment of the surface. 
  8. There is possibility of damages because of sparks. 
  9. Conventional machining techniques produce more improved fatigue properties than ECM.  

Applications of Electrochemical Machining ECM 

  • ECM is mainly used in the areas where conventional machinig techniques are not feasible . One of the main applications of ECM is found in the aerospace industries where accuracy is very important when complex shaped difficult to machine materials are needed to be machined. 
  • Different Industrial techniques have been developed on the basis of Electrochemical Machining Such as 
                a. Electrochemical Cutting 
                b. Electrochemica ECM 
                c. Electrochemica broaching 
                d. Electrochemica drilling 
                e. Electrochemica deburring 

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Miller TIG Welder - Dynasty Series Review and Classification

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Miller Welders are one of the most famous manufacturers of TIG welding equipment. Performing TIG welding perfectly is an art. And for a clean, successful and accurate TIG weld we need efficient welders and efficient welding machine. Miller TIG welder always comes handy in achieving the desired weld. Miller manufactures two types TIG of welding equipment

  1. AC/DC all type metal welder (including aluminum).
  2. DC Steel alloy welder. 
The first type includes three different Miller TIG welder which includes 
  • Dynasty Series
  • Diversion Series and 
  • Syncrowave Series 
The second type have only one series named - Maxstar Series . In this article I will talk about the Dynasty series and its classification.

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Miller TIG Welder - Dynasty Series Types 

Miller Dynasty welders have the advanced technology which makes it flexible for AC/DC. stick or TIG solutions. It has the inverter technology. 

Features 
  • Compact and mobile design producing ease of opearion. 
  • Superior weld quality and arc performance.
  • Low cost of installation and maintenance .  

Dynasty Models 

Miller TIG welder Dynasty Series Review

Dynasty 200 

  • Portable only 45 lb 
  • Input voltage - 120-460 Volts 
Applications of Miller Dynasty 200 
  1. Fabrication
  2. Aerospace
  3. Can be used in Food and beverage company
  4. Suitable for petroleum or chemical indsutries
  5. Useful for Mechanical Contractors 
  6. Repair/ maintenance of different metals 
  7. Aluminum product building 

Dynasty 280 

  • Input voltage 208-575 volts 
  • 3 phase or single phase power 
  • Two models - 280 and 280 dx 
  • weight 52 lb
  • Adjustable shoulder strap 
  • Pro-set feature available 
Application 
  • Fabrication
  • Aerospace
  • Anodized aluminum fabrication can be done 
  • High precision-fabrication can be done 
  • Heavy industry uses 
  • Aluminum ship building, repair and maintenance 

Dynasty 350/700

  • Programmed memory
  • Independent AC current control 
  • Input power 208-575 volts 
Application of Dynasty 350 /700 
  • Fabrication
  • Aerospace
  • Anodized aluminum fabrication can be done 
  • High precision-fabrication can be done 
  • Heavy industry uses 
  • Aluminum ship building, repair and maintenance 
  • Its application includes marine fabrication. 

Dynasty model steel and aluminum welding capability 

steel and aluminum welding capability

Dynasty Quick Specs 


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Catalytic converters- Dual bed and three way catalytic converters

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Catalytic Converters 

Catalytic converter is a  way of treating exhaust gases. These convert harmful pollutants into harmless gases. A catalyst is a material that causes chemical change without entering into chemical reaction. In effect the catalyst encourages to react with each other. For example, in the HC/CO catalytic converter, the catalyst encourage5 the HC to unite with oxygen to produce H20 (water).It encourages the CO to change to CO2 (carbon dioxide). The catalyst in the NOx converter splits the nitrogen from the oxygen. The NO therefore becomes harmless nitrogen and oxygen. Figure 31-40 shows that a two way type catalytic converter that converts only HC and CO. Figure 31-40 also shows that the flow of the exhaust gas through the converter. The converter is filled with BB-shot-size metal pellets. They are coated with a thin layer of platinum or similar catalytic metal. The pellets form a matrix through which the exhaust gas must pass. As the exhaust gas flows through the catalyst produces the chemical reaction. Another type of catalytic converter must use non-leaded gasoline. If the gasoline contains lead, the lead will coat the catalyst and the converter will stop working. If this happens to the pellet type converter, there is a way to remove the old pellets and put in a charge of fresh pallets. But in the honey-comb type, the complete catalytic converter must be replaced.
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Dual bed and three way catalytic converters 

There are three general categories of catalytic converters .These are oxidizing, reducing, and three way. The oxidizing converter handles handles HC and CO, using platinum and palladium as the catalyst. To control NOx, rhodium is used as a reducing catalyst. It changes NOx to harmless N2. Instead of having two separate catalytic converters in the exhaust system, one for HC and CO and the other for NOx, most manufacturers use either a dual-bed catalytic converter or a three-way catalytic converter.
catalytic converters


A dual bed converter (Fig 31-42) is like two bead type converters in one housing with an air chamber between them. The exhaust gas first passes through the upper bed, reducing the Nox and oxidizing some of the HC an CO. Then the exhaust gas flows through the air chamber to the lower bed, where the air pump is adding sufficient air for final oxidizing of the HC and CO.

catalytic converter
A three-way catalyst is a mixture of platinum and rhodium (sometimes mixed with palladium). It acts on all three of the regulated pollutants (HC, CO and Nox), but only when the air-fuel mixture ratio is precisely controlled (Fig 31-43). If the engine is operated with the ideal of stoichiometric air-fuel ratio of 14.7:1, the three-way catalyst is very effective. It strips oxygen away from the Nox to form harmless water (H2O), carbon dioxide (CO2 and Nitrogen (N2). However, the air-fuel mixture must be precisely controlled if thus action is to occur. For this reason, a closed-loop fuel-metering system (either feedback carburetor or fuel injection) must be used. 

Dual bed and three way catalytic converters


There are two types of three way catalytic converters. They have a mesh or honeycomb (Fig 31-44) coated with catalyst. The front section (in the direction of the gas flow) handles NOx and partly handles HC and CO. The partly treated exhaust gas then flows through the air chamber into the rear section of the converter. There the gas mixes with the air being pumped in by the air pump. This is called secondary air. It puts more oxygen in the exhaust gas to that the two way catalyst can take care of the HC and CO.

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Biomass-Advantages and Disadvantages

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Biomass - Important facts 

Biomass advantages and disadvantages are associated with some very important facts. Day by day the conventional energy sources like fossil fuels is reducing. Finding sources for conventional energy is a very complicated and lengthy process. But with the increasing population, the need for new energy sources is also rapidly increasing in developing countries and in rural areas. Sometimes the grid power is not economically feasible to expand in those areas. In many south Asian countries like India, Bangladesh and Pakistan biomass is the first choice when it comes to the production of heat for cooking. Here you can find the impact of renewable energy on the global warming in India. The most important biogas plant found in India is Fixed Dome Type Janata Model. 

Biomass-Advantages and Disadvantages
image courtesy: http://renewableenergyhub.com/

Definition of biomass fuel?

Biomass is naturally produced from plants and animals. It is natural and organic. Biomass is one of the most cheapest non-conventional energy sources because it is produced from micro organisms. Biomass stores energy from sunlight by the photosynthesis process. Though it is cheap and clean it is not a popular form of energy source like fossil fuels. Especially in the developed countries biomass has lost its popularity. But in the rural areas biomass is widely used in small industries and for cooking purposes. Some examples of biomass fuels are wood, manure, animal and human wastes, crops, manure etc. In the last two decades biomass has become very common alternative energy. 

Classifications of biomass 

Biomass is generally classified in two big classes 
  1. Solid biomass  like - weeds, agricultural residues, coconut shells, cotton stock con cob etc. 
  2. Powdery biomass like - rice husk, ground, cofee husk, sugarcane smashes parts etc. 


Biomass advantages and disadvantages 

If you talk about the advantages and disadvantages of biomass energy then we will see that there are very few cons. There are different techniques for the energy harnessing. One of the biggest disadvantage of biomass energy is that sometimes some biomass fuels are needed direct burning. Wood or dried cow dung cakes are some of the sources which need direct burning. And this can cause some pollution. So if not taken care of, biomass can produce severe environmental problems as it releases a lot of carbon. As a result the balance in the ecosystem can be hampered. 
We cannot deny the fact that biomass can be a good alternative fuel to fossil fuels. Biomass can be collected from various sources. So if this energy is harvested in a way that creates negligible harm then it can dispel some of the energy crisis of the world. So for the proper use of the biomass energy , appropriate policy should be made. Awareness about the potential biomass energy advantages and disadvantages should be created. All the energy sources have their own advantages and disadvantages. With proper guidelines and policy biomass can be a great sustainable and low cost clean energy. Like any other energy sources there are advantages and disadvantages of using biomass energy. Let's discuss about them: 

Advantages
  • Biomass energy is renewable or alternative. 
  • Biomass is carbon neutral. 
  • It is  inexhaustible fuel source. 
  • Biomass produces very low amount of  carbon compared to fossil fuel energy;
  • The environmental impact is minimum if the direct burning burning is avoided. Instead of that fermentation or pyrolysis can be used 
  • Alcohol and other forms of fuels produced from biomass is very clean burning and environment friendly. 
Disadvantages
  • Fossil fuels are more efficient than biomass fuels. 
  • Sometimes biofuel production can be proved a little expensive. 
  • Some biomass production plants need a lot of space to grow the raw materials of the plant (crops and plants)
  • Direct burning can produce pollution by particulate emission. 

Conclusion

In developing and rural areas biomass is still used in heating purposes and also for cooking. Using biomass farmers can do their agricultural activities. These days almost 16% of the world's total energy supply from biomass. In developing countries 40% of the rural supply come from the biomass energy. A number of environmental groups are strongly opposing the wide use of forest biomass use because of high carbon emission. For the better realization of biomass advantages and disadvantages, I think this post will be very helpful. Biomass fuels can be great option to replace the fossil fuels as a source of  power generation in rural, developing as well as developed countries. 

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Tidal Energy - Advantages and Disadvantages on electricity generation

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Tidal Energy - How Tidal energy works- An introduction 

All flowing water carry with them kinetic energy. When such water encounters a turbine, part of the momentum of the flowing water is transferred ton to the turbine, causing it to rotate. The rotation of the turbine cam then be used to generate electricity. So for electricity generation purpose we must know about tidal energy advantages and disadvantages.  Whether the water is om the open ocean, an estuary or a river, its motion can thus be utilized in generating energy. The tides occurring in the oceans are one such source of energy based on the movement of the water. If we analyze the tidal energy pros and cons then we will find that tidal energy is renewable and the output of this energy varies with the variation of the tidal range.

Now How tides are generated ?

  • Tides are generated by the gravitational forces of the sun and moon on the oceans. 
  • by the spinning of the earth around its axis 
  • and the relative positions of the earth, moon and the sun. 

 What are tides and tidal current ? 
Tides are the periodic vertical rise and fall of ocean water. The period between consecutive high tides is 12.5 hours. The tidal rise and fall of water is accompanied by periodic horizontal and to and fro motion of water called tidal currents. Tides and tidal current is intimately related. So we are already a getting an idea about the pros and cons of tidal power.

Difference between Tidal Energy and Wave Energy 


  • Tidal energy differs from wave movement. Waves have a period of only about 6 seconds, whereas tides have a period of about 12.5 hours. 
  • Waves are caused by surface winds, whereas tides are caused by the gravitational forces of sun and moon on ocean water. 
Have a look - 

The amplitude of tides covers a wide range from 25 cm to 10 m. The speed of the tidal currents is in the range of 1.8 km/h to 18 km/h. The tides and and tidal currents possess renewable energy. The rise and fall of water follows a sinusoidal curve.

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Advantages and disadvantages of tidal energy to generate electricity 

Advantage 
  1. The biggest advantage of tidal power, besides being inexhaustible, is that it is completely independent of the uncertainty of precipitation (rain). Even a continuous dry spell of any number of years will have no effect whatsoever on the tidal power generation.  
  2. A great environmental advantage of tidal power generation is - its free from pollution because it does not use in any fuel and also does not produce any unhealthy waste like gases, ash or atomic refuse. 
  3. Electricity generation from tidal power  do not require large areas of valuable lands because they are mainly on the seashore, 
  4. Peak power demand can be effectively met when it works in combination with thermal or hydroelectric systems. 
advantages and disadvantages of tidal energy


Disadvantage and solutions to tidal energy cons 

 There are a number of reasons why the power generation is still novelty, rather than a normal source of energy, The reasons are -


  1. The fundamental drawback to all methods of generating tidal power is the variability in output caused by the variations in the tidal range. 
  2. The tidal ranges are highly variable and , thus the turbines have to work on a wide range of head variation. This is a great disadvantage of using tidal energy to generate electricity as this affects the efficiency of the plant. 
  3. Since the tidal power generation depends upon the level difference in the sea and an inland basin, it has to be intermittent operation, feasible only at certain stage of tidal cycle. This intermittent pattern could be improved to some extent by using multiple basins and a double cycle system. 
  4. The tidal range is limited to a few meters. As bulb turbine technology was not well developed for this range, use of conventional kaplan runners was the only alternative. This was found to be unsuitable. Now, with the development of reversible flow bulb turbines, this difficulty is overcome. 
  5. The duration of power cycle may be reasonably constant, but its time of occurrence keeps changing, introducing difficulty in the everyday planning of the load sharing grids. This handicap can be removed now with the help pf computerized programming. 
  6. Sea water is corrosive and it was feared that the machinery may get corroded. Stainless steel with a high chromium content and a small amount of molybdenum and the aluminium  bronzes proved to be good corrosion resistant at La Rance project. The vinyl paint exhibited good results. 
  7. Construction in seas or estuaries is found difficult. 
  8. Cost is not favorable compared to the other sources of energy. 
  9. It is feared that the tidal power plant would hamper the other natural uses of estuaries such as fishing or navigation. 

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Advantages and Disadvantages of Wave energy

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Wave Energy - A steadier Renewable energy than Wind 


Waves are increasingly generated in oceans and large lakes; at times the waves are strong enough to overturn large ships or toss them ashore.
Gravitational attraction of the sun and the moon as well as the force of wind are mainly responsible for the wave being created. Oceans are efficient collectors of wind energy; indeed waves are a source of energy steadier than the wind, because once wind generates a wave, the latter conveys the energy it had derived from the wind over immense distances with only moderate dissipation. It is another matter that wind energy has always proved far more easier to harness than wave energy. Wave energy may vary from a few watts to kilowatts per meter which is fluxed in the open sea or against coasts . Greatest power is achieved in winter and smallest in the summer, mainly in the zones of the prevailing westerlies and trade winds. 
Both vertical as well as horizontal movement of the water contributes to wave energy. Every particle of water experiences almost a circular motion moving up and down reaching the crests and troughs.  

Wave energy Advantages and Disadvantages 

Advantages 

1. Wave energy has this advantage over solar or wind energy that the energy has been naturally concentrated by accumulation over time and space and transported from the point at which it was originally present in the winds. 

2. A much greater amount of power is concentrated in the waves than in the wind. If we compare the power concentrated in a good wind energy to the corresponding area having wave energy then we will find that wave energy is 100 times greater than wind energy.

3. It is a free and renewable energy source. 

4. Wave power devices do not need huge land masses like solar energy wind energy. 

5. These devices are almost pollution-free. After removing the energy from the waves waters are left in a placid state.

6. No wastes or greenhouse gases are produced in the process. In my opinion this is the most important advantage of wave energy. 

Disadvantages 

1. The major demerit of wave energy, in comparison to wind, is that the energy is available in the ocean. So the equipment needed for the extraction of wave energy must operate in a marine environment. The lifetime and reliability is a great factor which should be taken care while constructing the equipment. The transportation of energy is a great factor because the energy produced needed to be transferred to a great distance from the shore. 

2. Wave energy converters must be capable of withstanding very severe peak stresses in storms. 

3.  Finding a proper site for the extraction of energy from the wave is pretty tough because wave energy is totally related to ocean! 

4. Devices needed for the harnessing of the wave energy are very complicated.  

5. Many economic factors are important in the installation of a wave energy based power plant. These factors are capital, maintenance cost, repair cost as well as replacement cost. For the power generation companies economic factors can play as the major disadvantage of wave energy.

For a better and green house effect free world, renewable energy sources are the most preferable option. So after going through the advantages and disadvantages of wave energy the leaders of the world, power generation companies along with engineers should take some initiative to make the best use of wave energy.
advantage and disadvantage of wave energy



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Bernoulli's Equation and Euler's Equation - Different terms

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Bernoulli's Equation states that - 

For an incompressible liquid (density constant) which is flowing in a continuous stream; the total energy remains the same for all the particles, when the particle is moving from one point to another point.

Mathematical expression of Bernoulli's equation:

P1/w + (v2 )1/2g + z1 = P2/w +( v2)2 /2g + z1 = constant 

Here 
P1 , P2 = Pressure at points 1 and 2
V1,V1 = velocity at points 1 and 2
Z1 , Z2  = datum head at points 1 and 2
w= weight density of the liquid (also denoted by Greek letter gamma)

Please read : A Complete Guide to Fluid Mechanics 

Different types of energies or head in Bernoulli's equation 

1. Potential energy or potential head: 

Potential energy is the energy stored in a body because of changing its position above the fixed datum head. It's denoted by Z. 

2. Kinetic energy or head: 

It is due to the velocity of the fluid. It is denoted by v2 /2g.  Here, v is the velocity and g is the gravitational acceleration. 

3. Pressure energy or pressure head:

 This energy is due to the pressure of the liquid. It is denoted by P/w . 

P has the unit Newton/square meter ,N/m2 
W has the unit Newton / cubmic meter , N/m3

So, 
Total Energy = Pressure energy + Kinetic energy + Potential energy 
Total Head = Pressure Head + Kinetic Head + Potential Head  

Applications of Bernoulli's Equation: 

1. A modified equation for the measurement of velocity in a pitot tube and pitot static can be got from Bernoulli's equation. 
2. The flow through venturi meter and orifice meter can be measured by this equation. 
3. Flow over notches and weirs can be calculated. 

Euler Equation or Bernoulli Differential Equation 

bernoullis equation

Euler's equation is expressed as 

dp/ρ + g.dx + v.dv = 0 

Euler's Equation is based on some assumptions: 

1. Non-viscous flow. 
2. Incompressible  and homogeneous flow. 
3. Steady flow. 
4. Continuous flow. 
5. Uniform velocity of the flow. 


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Pros and Cons of Solar Energy

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The energy from the sun reaching the earth per day ranges from about 600 Btu (British Thermal Unit) / square feet for Northern Europe to about 2000 Btu/square feet for arid regions near the equator. More energy from sun strikes the earth in one hour than all energy consumed on the planet in a year! A summer day’s sun at noon provides a square, meter of land with a power input almost a kilowatt. One might wonder why solar energy has not replaced the conventional energy sources, not even a significant fraction. So there are definitely some pros and cons of solar energy. In this article I will discuss about the pros as well as cons of this vast energy source.

Pros and cons of solar energy

Pros of Solar energy


No pollution

There is no pollution while producing energy from the solar panels. Only pollution we can talk about is the pollution that can happen while making the solar panels.

Great for household use 

Theoretically the sunlight falling on a typical single house can easily provide from one third to one half of the heating needs of that house anywhere in hot countries even in the cooler climates and even when there is persistent cloudiness.

Zero dependence on the fossil fuels 

The dependence on the fossil fuels can be reduced a great deal. In one day the solar energy falling on India alone is greater than the energy in their present annual coal consumption. 

Reasonable Cost 

One installed the cost of electricity production is very low though the cost of producing solar cells are high. And in the remote areas the installation cost will be comparatively very low.
Solar panels can be set up in the house roof tops. So there is no requirement of finding spaces for installing the solar panels.

Availability 

Most of the areas of the world are exposed to the sun’s rays and capable of using this energy very easily.

No transportation cost of fuels 

No need of transportation of fuels from one place to another. The fuel is everywhere!

The harnessing of electricity is very much easy in the remote areas when these areas are not connected to the national grid. 

Cons of Solar energy


Cost

The solar energy has not been the prevailing one because of its cost. The primary reason is clearly the cost of solar energy based technology, especially in comparison to the lower priced commercial fuels.

Some adverse environmental effects of solar energy

Large scale utilization of solar energy is associated with adverse environmental effect. To produce an electrical equivalent of 10 terra watt of solar electricity a land area as big as 220000 square kilometer will be required. An area of this size cannot be covered with solar energy collecting devices without making any adverse environmental effect.

Storage of captured energy

The devices for storing solar energy are of low efficiency and high costs. This can cost thousands of dollars for a buyer to set up a solar panel in houses as well as in factories. 

Though there are some cons of solar energy in the near future we must find a way to properly utilize solar energy because the fossil fuel storage are at the verge of getting finished. And the harm occurred due to the use of these solar energy is irreparable. So Solar energy pros and cons should be properly studied.

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Impact of Renewable Energy Sources on Global Warming in India

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 A brief story of global warming- global warming skepticism 

Of all the forecasts of global environmental disasters made from time to time, the one which aroused the most widespread skepticism was about global warming. Even as several well-meaning people took it seriously- some rather too seriously- a whole lot of other scientists and policy-makers dismissed it as over-exaggeration. During 1970s through 1990s, those who believed in global warming talked of it as soon as they felt a day was hotter than the previous one. Others believed that even if the world continued to produce gases which cause greenhouse effect, our oceans would keep assimilating them and no long-term global warming will ensue. They dismissed episodes of extreme climate as the usual fluctuations that occur in nature. Indeed during the late 1960s and early 1970s, it was the forecast of global cooling that had captured public imagination (Gribbin, 1975; Thompson, 1975; Peterson et al, 2008).

Global Warming A Scientifically Accepted Fact  

During the last 20 years, the balance of evidence has gradually and decisively shifted towards global warming. It is now a scientifically accepted fact that global warming is indeed occurring and that it will have long-ranging impacts on the earth’s ecosystems. There is no longer a disagreement on the existence of global warming; if there are disagreements, they are on the extent of harm global warming will cause. There is also near-complete consensus that use of fossil fuels is the principal cause of global warming and unless the emissions to atmosphere of CO2 and other greenhouse gases are drastically reduced, global warming will progressively increase and lead us to our doom.

Adverse Effects of Global Warming 

      So, global warming has already hit us, and it is beginning to hit us harder. It has also produced another monster which may me even more destructive than temperature rise and ocean acidification .Given that 70% of the world is covered by oceans, any disturbances in oceans can have bigger and ‘deeper’ effects on earth than the disturbances in the rest of the 30% of the world!

Global Warming and Renewable Energy Source: India and the world 


Once again, there is a groundswell of demand for ‘alternative energy sources’, particularly the ‘renewable’. Even before global warming became an accepted reality in the post-modern era, fossil fuels were almost universally perceived as highly ‘unclean’ fuels responsible for numerous forms of gross pollution, including acid rain. On the other hand, non-conventional energy sources, especially the renewable energy sources, have created a ‘clean’ image regarding environment impacts. But obviously there is exception, one of the major exceptions is the large hydropower projects. Past experience showed us that they can be catastrophic for the environment. Now it is believed that mini-hydel and micro-hydel projects can be proved harmless for alternatives.



The tide has turned so strongly in favour of renewable that for the first time ever since the dawn of the fossil fuel era over two hundred years ago, renewable energy technologies have attracted more investment globally, ($140 billion) in 2008, compared with $110 billion for fossil fuel-based technologies according to figures released by the United Nations, June 2009 (Macalister, 2009). Wind energy has attracted the highest new worldwide investment, $51.8 billion, followed by solar at $33.5 billion. Biofuels are the next popular investment, winning $16.9 billion. There is as much as a 27% rise to $36.6 billion in developing countries led by China, which pumped in $ 15.6 billion, mostly in wind and biomass plants. India’s overall spending on renewable energy has risen to $4.1 billion 2008, 12% up on 2007 levels.

India has started Spending on Renewables to reduce global warming and pollution 


         According to India’s Ministry for New and Renewable Energy (MNRE, 2009), India has a potential of generating over 82000 MW (8.2 GW) of power from just wind, small hydro and biomass (Table 1.1). Of this, only 6100 MW, i.e., a mere 7.4% of the potential is presently being realized. There is a similarly vast potential for dispersed units, but only a small fraction has been realized (Table 1.2). Which is why India has stepped up its spending on renewable, just as the rest of the world has. It as if the world is preparing to stake it’s all on renewable in the hope that renewable will save it from the looming disaster of global warming and irreversible pollution.

Table 1.1 : Potential of Power Obtainable from wind, small hydro and biomass in India vs its actual realization at present (MNRE, 2014)

Impact of Renewable Energy Sources on Global Warming in India


Table 1.2 : Potential utilization of biogas and dispersed solar energy, biomass and wind energy systems in India and the present state of its realization (MNRE, 2014)
Statistics of renewable energy sources in India, 2014


These links gives glimpses of the renewable energy sources. It also addresses these tricky questions: are renewable energy sources really as benign as is widely believed? Are they really a sure answer to the problem of global warming?

Is there any major proof that Renewables are environment friendly ? 



One may say that for thousands of years when humankind was dependent almost totally on renewable, the world was much less polluted and there was no global warming. Is this itself not a major proof that renewable are environment-friendly?

Sadly, it isn’t!

The reason is that till the mid-18th century the global population and the per capita energy consumption, hence the total global energy consumption, were small fractions of what they are today. Had we used fossil fuels at the rate renewable sources were being used till 1850, we would not have experienced global warming. But at the present rate of population growth and per capita consumption no source of energy, however, clean it may be, can bail us out of rapidly increasing global warming and other forms of pollution. 

India, in its National Electricity Policy 2005 (MNRE, 2009), has set for itself the goals of, among other things: (a) access to electricity for all and (b) increase in per capita availability to over 1000 units by 2012. In other words, we want to greatly enhance energy consumption. In doing it, we will have to face the inevitable consequence of more serious pollution. And, as we will bring out in the next articles that renewable aren’t as squeaky clean as are popularly believed. Nor is the use of renewable energy sources on a large scale an insignificant burden on the environment.


   


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