Solar energy nuclear power and wind mills are the three common renewable energy sources that are easily available. Their details, limitations and issues are also mentioned below:

Solar Energy

The most popular and simple way of alternate energy is solar energy i.e. the electricity produced by sun's radiation. There are two methods of achieving the above-mentioned goal:

1. Photovoltaic Cells



A photovoltaic cell converts sunlight directly into electricity. These cells normally produces 1-2 Watts of electricity which is not sufficient enough to operate appliances, therefore a number of such cells are bound together to form large modules and even these modules can be connected to form arrays to produce required power output. PV systems can easily be used at any remote site like RF stations. They are also used to power watches, calculators, road signs and streetlights. Electricity produced by these modules produces Direct Current (DC) whereas the normal home appliances that we use are Alternate Current (AC) appliances therefore an inverter is required to convert the DC into AC.

2. Solar Power Plants

They indirectly generate electricity when the heat from solar thermal collectors is used to heat a fluid that produces steam to move the turbine that is connected to ordinary generators.

Limitations

The output of solar energy systems depend on amount of solar radiation produced by the sun at that particular site and at that particular time of the year. Moreover, the PV modules are only 18% efficient however; efforts are being made to increase their efficiency to a remarkable level. 

Wind Mills



The windmill systems includes wind turbine with a conventional generator. The wind flowing produces mechanical energy in a turbine that is converted into electricity from a conventional generator coupled to the turbine. These systems works essentially the same as generation from fossil fuels except that instead mechanical energy produced by using steam it is produced from the combustion of fossil fuels, the mechanical movement is produced by the wind flow. Modern wind turbines range from 600 kW to 5 MW of power output, although turbines with rated output of 1.5–3 MW have become very common for commercial use.

Limitations

The power output of a turbine is a function of the cube of the wind speed, so as wind speed increases, power output increases. Areas where winds are stronger and more constant, such as offshore and high altitude sites are preferred locations for wind farms. Since wind speed is not constant, the energy production also varies.

Nuclear Power Plants

Nuclear power plants normally use nuclear fission reaction to produce energy. In fission the nucleus of large, atoms such as uranium 235 or plutonium 239, is split into two or more smaller nuclei producing large amount of kinetic energy along with free neutrons and gamma radiation. The free neutrons are used to produce more such fission reactions. A cooling system removes heat from reactor core and transports it to the area where thermal energy is used to heat fluid producing steam to rotate the turbine coupled with conventional generators.

Issues

It is fact that the nuclear waste is hazardous to the environment but these risks can be eliminated by using improved method to handle the waste products. Moreover, nuclear reactors produce virtually no air pollution and the energy produce is much higher than the fossil-fuel generators. In addition, nuclear power produces far less waste material than fossil-fuel based power plants. Coal burning plants are particularly noted for producing large amounts of toxic and mildly radioactive ash due to concentrating naturally occurring metals and radioactive material from the coal.

Limitations

The nuclear power plants have high initial investment and the maintenance cost is also very high.

Conclusion

The renewable energy systems use fuel that has unlimited reserves, free of cost and generalized existence like sun-rays for solar systems and air for wind mill systems, even uranium for nuclear power plants are very abundant in nature. It is approximately as common as tin or germanium in Earth's crust, and is about 35 times more common than silver. In addition, more importantly they are none or far less pollutant than the conventional sources.

However, these renewable energy systems produce no air or water pollution but do have some indirect impacts on the environment. For example, manufacturing the photovoltaic cells used to convert sunlight into electricity consumes silicon and produces some waste products. In addition, large solar thermal farms and windmill can also harm desert ecosystems if not properly managed.

Man in the name of technology and scientific advancement does these damages to the Mother Earth like the weapons that we make to safe lives are actually killing ourselves by one way or the other. It is we who in the blind quest of technological advancement had willing or unwillingly destroyed the entire ecological system and it is our prime duty now to save it as our survival depends on its existence.

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Tag: Solar Energy vs Wind Mills vs Nuclear Power