A Comparative Study Paper: Power Generation -Conventional and Renewable Energy Sources – Duvvuri Venkata Lalitha, Penneti Ujwala & Adari Bhuvaneswari

January 25, 2014 Yuva Engineers Electrical Engineering 0

Title: A Comparative Study Paper: Power Generation -Conventional and Renewable Energy Sources

Authors: Duvvuri Venkata Lalitha, Penneti Ujwala & Adari Bhuvaneswari, 3rd Year, BTech, EEE Department

College: Dr.L.Bullayya College of Engineering (for women), Visakhapatnam

ABSTRACT:

Electricity generation is the process of generating electric power from the energy sources such as Renewable and Non-renewable, conventional and non-conventional methods. Renewable and Non-renewable power generation includes electric power generated by renewable and non-renewable (which can renewed and which cannot be renewed) energy sources such as solar, wind, tidal, thermal etc. Conventional and Non-conventional power generation includes electric power generated by conventional and non-conventional methods such as coal, petroleum, natural gas etc.

 INTRODUCTION:

The conventional sources of energy are generally non-renewable sources of energy, which are being used since a long time. These sources of energy are being used extensively in such a way that their known reserves have been depleted to a great extent. The coal, petroleum, natural gas etc., are conventional sources of energy.

With the rising cost and decreasing availability of nonrenewable fossil fuels, renewable resources are receiving increasing attention and also these are pollution free. We can regenerate or replenish them. Biomass, water, geothermal, wind and solar are the Renewable Energy sources

ELECTRICITY GENERATION USING COAL (Conventional Energy Source):

Thermal power station turns the chemical energy in coal into electrical energy that can be used in homes and businesses.

COAL:  Coal is one of the most important sources of energy and is being used for various proposes such as heating of housed, as fuel for boilers and steam engines and for generation of electricity by thermal plants.

a. Coal burning: First the coal is ground to a fine powder and sent into the boiler, where it is burned, converting its chemical energy into heat energy. As well as heat, burning coal produces ash and exhaust gases. The ash falls to the bottom of the boiler and is removed by the ash systems. The gases enter the exhaust stack, which contains equipment that filters out any dust and ash, before venting into the atmosphere.

b. Mechanical Energy:  Burning the coal heats water in pipes coiled around the boiler, turning it into steam. The hot steam expands in the pipes, so when it emerges it is under high pressure. The pressure drives the steam over the blades of the steam turbine, causing it to spin, converting the heat energy released in the boiler into mechanical energy.

c. Electrical Energy: A shaft connects the steam turbine to the turbine generator, so when the turbine spins, so does the generator. The generator uses an electromagnetic field to convert this mechanical energy into electrical energy. After passing through the turbine, the steam comes into contact with pipes full of cold water. The cold pipes cool the steam so that it condenses back into water. It is then piped back to the boiler, where it can be heated up again, turn into steam again, and keep the turbine turning.

d. Finally, a transformer converts the electrical energy from the generator to a high voltage. The national grid uses high voltages to transmit electricity efficiently through the power lines, homes and businesses that need it. Here, other transformers reduce the voltage back down to a usable level.

We can generate electricity using oil and natural gas but from the past decades we are generating 50% of electricity using coal and remaining by the other sources due to the advantages of coal and disadvantages of natural gas and oil.

DISADVANTAGES OF NATURAL GAS FOR GENERATING ELECTRICITY:

  1. Natural gas is pollution free but when it burns, carbon dioxide, monoxide, and other carbon compounds are emitted in the atmosphere contributing to the greenhouse effect.
  2. Natural gas is cheap in cost but the transportation cost is high.
  3. During the transportation or in any another situation. Natural gas is extremely dangerous. Such leaks may be the cause of fire or explosions. The gas itself is extremely toxic when inhaled. The main risk comes from the fact that it is naturally odorless and cannot be detected by smell, unless an odorant has been added to the gas mixture. In the case of an underground leak, the odorant may gradually become weaker and the gas may go undetected.
  4. It is a finite source of energy and cannot be considered a long-term solution to our energy supply problem.
  5. The whole pipe installation may be very expensive to construct since long pipes, specialized tanks, and separate plumbing systems need to be used. Pipe leakage may also be very expensive to detect and fix.

DISADVANTAGES OF OIL FOR GENERATING ELECTRICITY:

The cost of oil is low but disadvantages are more for oil for producing electricity. And the disadvantages are as follows:

  1. Not sustainable.
  2. Produces carbon dioxide, which causes greenhouse effect.
  3. Requires sustainable amount of cooling water.
  4. The world’s oil reserves are limited.
  5. If the oil spills while transporting, causes severe pollution and affects the marine species.
  6. Some oils contain high levels of sulphur.

When compared to the use of natural gas and oil for generating electricity use of coal is more convenient. Some of the advantages of coal for generating electricity are as follow: 

ADVANTAGES OF COAL FOR GENERATING ELECTRICITY:

  1. Burning of coil is currently one of the cheapest ways to generate power comparing with energy sources of energy.
  2. Power stations can built anywhere with good transport links or access to gas pipelines and a plentiful supply of cooling water.
  3. The world has many coal reserves.
  4. For cooling purpose Gas can be easily transported by pipeline as it is light in weight.

Not only are these advantages but there some disadvantages of using coal to produce electricity. Those disadvantages are 

DISADVANTAGES OF COAL FOR GENERATING ELECTRICITY:

  • Coal is not a Renewable energy source. So, we may lose the coal reserves.
  • Thermal Power stations require large amounts of fuel to produce the less amount of electricity which results in wastage of fuel.
  • Causes pollution when compared to another sources. Coal emits less percentage of harmful gases into atmosphere.
  • Requires more water for the thermal power plant.
  • Very large quantities of ash have to be disposed of and a lot of smoke is produced.
  • The methods of mining coal can be very destructive; although responsible coal miners do a remarkably good job of restoring the land after the coal has been mined off.
  • These coal mines are getting reduced day by day because of the extensive use of the coal for generating electricity in large amounts for development in all the fields. Also electricity produced by coal causes the environmental pollution and In future these coal mines may completely vanished. It cannot be renewed or reused again so, there is need to develop the Renewable methods of generating electricity such as solar energy, tidal energy, wind energy etc.

Hence it was proved that we have disadvantages if we consider coal as a usage of generating electricity. So let us discuss about the Renewable energy sources.

ELECTRICITY GENERATION BY SOLAR ENERGY (Renewable Energy Source):

Photovoltaic devices, or solar cells, directly convert solar energy into electricity. Individual solar cells grouped into panels range from small applications that charge calculator and watch batteries, to large systems that power residential dwellings. Photovoltaic power plants and concentrating solar power plants are the largest solar applications, covering acres.

Sun: The sun has been producing energy in the form of heat and light since the Earth is formed. Solar energy systems do not produce emissions and are often not harmful to the environment. Thermal solar energy can heat water or buildings.

sun

Solar panels turn energy from the sun’s rays directly into useful energy that can be used in homes and businesses. There are two main types: solar thermal and photovoltaic, or PV. Solar thermal panels use the sun’s energy to heat water that can be used in washing and heating. PV panels use the photovoltaic effect to turn the sun’s energy directly into electricity, which can supplement or replace a building’s usual supply.

Working of photovoltaic cell: PV panel is made up of a semiconducting material, usually silicon-based, sandwiched between two electrical contacts. To generate as much electricity as possible, PV panels need to spend as much time as possible in direct sunlight.  A sheet of glass protects the semiconductor sandwich from hail, grit blown by the wind, and wildlife. The semiconductor is also coated in an antireflective substance, which makes sure that it absorbs the sunlight it needs instead of scattering it uselessly away.

Getting Electrical energy: When sunlight strikes the panel and is absorbed, it knocks loose electrons from some of the atoms that make up the semiconductor.  The semiconductor is positively charged on one side and negatively charged on the other side, which encourages all these loose electrons to travel in the same direction, creating an electric current. The contacts capture this current in an electrical circuit.

Converting DC to AC: The electricity PV panels generate is direct current (DC). Before it can be used in homes and businesses, it has to be changed into alternating current (AC) electricity using an Inverter. The inverted current then travels from the inverter to the building’s fuse box and from there to the appliances that need it.

inverter

PV systems installed in homes and businesses can include a dedicated metering box that measures how much electricity the panels are generating.

  • Solar panels can be arranged at the roof or terrace of our Homes and Industries or more number of the solar panels can be arranged in a large area like a power plant for huge amount of electricity. For reducing the use of large space we can place them on roofs or terrace.
  • We can generate the electricity using biomass, wind, tidal, etc renewable energy sources but we will get only less amount electricity compared to these all we get the maximum electricity from solar energy. It is the purest and cleanest form of energy we get freely every day by the sun we can make a best use of it by converting into Electricity for our development. And solar energy is pollution free, does not emit any harmful gases.

solar
ADVANTAGES OF SOLAR ENERGY:

  1. Non-polluting, no carbon dioxide like fossil fuels
  2. Free except for capital expenses.
  3. Longevity – solar panels can last over thirty years
  4. Environmental friendly because the conversion of energy does not produce any carbon dioxide.
  5. It is renewable. It comes from the sun, which is unlimited.
  6. Solar power costs less and is better for the environment, compared to burning fossil fuels and other electrical power
  7. It doesn’t have to be dug up from the ground like coal, oil, natural gas, or uranium
  8. It doesn’t have to be cut down, like wood from forests.
  9. We are using a renewable energy source like the sun, instead of non-renewable energy sources such as Gas, oil, fossil fuels etc…
  10. We can save power of electricity. Solar energy is not as much danger as electricity

DISADVANTAGES OF SOLAR ENERGY:

  1. It doesn’t produce much electricity for one single panel.
  2. If u were to build it on the ground, the cost will be higher [ for massive area of land]
  3. Only areas of the world with lots of sunlight are suitable for solar power generation
  4. The major disadvantage of solar power or solar energy is the cost of the photovoltaic panels
  5. e.      You need a lot of money to the installation of the solar power plant.
  6. f.        Least power energy at night time is another disadvantage of solar energy.
  7. There is no solar energy to be collected which means you’ll have to have adequate battery backup to get you through the nights
  8. Solar energy is not available 24 hours a day. It can only be harnessed well when it is the strongest, that is, excluding morning, evening and night.
  9. There is no guarantee of sunlight in stormy climate or during rain.
  10. Limited by environmental factors (like latitude and weather) 

APPLICATIONS OF SOLAR ENERGY:

Water heating and pumping-Heating water using electricity can be an expensive undertaking. Using applications of solar energy can help people to reduce their water heating and pumping costs.

Rural vacation homes-cottages and cabins may not have access to traditional power grids. If this is the case, these vacation homes can be designed to use solar energy so that vacationers can enjoy all the creature comforts of a hidden getaway.

Industrial uses-Most industries operate in environments where traditional power supplies are readily available. 

CONCLUSION:

  • Solar energy has great potential for the future. It does not pollute or otherwise damage the environment. It cannot be controlled by any one nation or industry. If we can improve the technology to harness the sun’s enormous power, we may never face energy shortages again.
  • By using renewable energy sources for generating electricity is a best way and we can save our non-renewable energy sources for future. And also we can save our environment.
  • So, in our view if we find out the solutions which can reduce some of the disadvantages of solar energy, we can eradicate pollution to some extent and we can also use the natural source which is not at all harmful in anyway
  • In Abroad solar energy is successful, like they are placing the solar panels on street lights and on roofs or terrace of buildings to avoid the using large power plants and free land which is not useful for constructing and agriculture.
  • In our India we can see Gujarat; It is also successfully generating the electricity using solar energy. In the same way we can make the best use of Solar Energy

REFERENCE:

http://en.wikipedia.org/wiki/Electricity_generation