Renewable energy sources for electricity generation

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THE TERM renewable is applied for that resource which is naturally occurring and renewed after a short period of time. Renewable energy resources are defined as the naturally occurring energy resources such as sunlight, wind, rain, tides, and geothermal heat etc. These resources are also called as clean or green energy because they do not pollute the environment.


Conventional energy resources such as oil, coal, and natural gas are effective driver of economic progress but at the same time adversely damaging the environment and human health. So to meet demand of energy, these renewable energy resources are frequently used. In contrast to other energy resources, renewable energy resources exist over a wide range of geographical areas.


Rapid development of renewable energy resource is based on its energy efficiency, climate change mitigation, energy security, and economic value. There is strong support for promotion of renewable energy resources such as solar energy as per International surveys.


The potential of renewable energy resources such as biomass, wind, solar, and geothermal is very high and can provide sustainable clean energy. The economic and policy mechanism is needed to support the wide spread dissemination and sustainable market for renewable energy system which has rapidly evolved. The supply is dominated by traditional biomass mostly fuel wood used for cooking and heating.


An overview of energy equation of Pakistan:


The availability of energy has a strong relationship with social and economic stability of any country. Pakistan is fundamentally an energy deficient country and its per capita energy consumption is 3894 KWh.


History of renewable energy resources:


In the mid 19th century, prior to the development of coal, nearly all the sources of energy were renewable. Oldest form of renewable energy resource is biomass that dates back nearly 790,000 years. Moving into the time of recorded history, renewable energy resources are human labor, animal power, water power, wind, and firewood. Development of solar engine continued until the outbreak of first world war. The IEA 2014 world energy oultlook project of renewable energy supply from 1700 gigawatts in 2014 to 4550 gigawatts in 2040.


Types of renewable energy resources:


There are following the types of renewable energy resources that given as below;


Biomass:


The biomass energy is obtained from the fossils of plants and animals. Most common form of biomass is wood. When we use the plants as biomass, we convert their stored energy from sun. Methane gas from the landfill and animal wastes is most common form of biomass. Ethanol and biofuel is most common and recent form of biomass which is obtained from the derivatives of plants and animals. In 1974, the Government of Pakistan started comprehensive biogass scheme. The units were designed to provide 3,000 to 5,000 cubic feet of biogas per day for cooking and household purposes. Biomass energy is projected to play a major role in future global energy supply.


Geothermal:


The energy produced by the heat of earth interior is called as geothermal energy. By drilling down to earth interior like the drilling of oil, we get heat to generate electricity. The natural heat within the earth (geothermal energy) is a good source for heating the houses and buildings. It is ancient type of natural source of heat energy from the earths core where the contiental plates slides over each other. Techonological advances have made it possible to drill into hydrothermal reservoir, pipe the steam or hot water to the surface and use the heat directly or to convert the heat into electricity.


The geothermal reservoirs across the globe have been susbtantially increased in the last few decades.


Water (Hydropower):


The energy contained in running water can be turned into electricity. Water stored in dams is released through turbine that spins the generator as the result elerciticty produced. There is wast unexploited potential worldwide for new hydroplants, particularly in the developing conutries of Asia, Latin America, and Africa. Hydropower continues to be more efficient way to generate electricity. Modern hydro turbines can convert as much as 90% of availabe energy into electricity.


Hydropower is important source of elerciticy in all over the world. While large dams have become much risker investement ther still remain much unexploited potential for small hydro projects around the world. Improvement and efficiency measurements are direly needed in dam structure, turbines, generator, substations, transmission lines, and environmental mitigation technology if hydro power role as clean renewable energy resource is to continue to be supported.


Wind:


Wind has considerable potential as a global clean energy resource being widely available. Wind energy is one of the proimary energy producing sources. Windmills are used in China, India and Persia for over 2000 years back for electricity generation.


The main techanical parameter to determine the economic success of wind turbine system in its annual energy output, which in turn determine the parameters such as average wind speed statistical wind speed distribution, distributing of occuring wind direction, turbelence, intensities and roughness of surrounding terrain. Accurate meterological measurement and wind energy map mecomes more commonly available wind project developers are able to more relaibly access the long term economic performance of wind farms.


Solar energy:


There are two basic categories of techonologies that convert the sunlight into useful form of energy, aside from biomass based system. First is photovoltaic module that converts the sunlight directly into electricity. Second is the solar thermal power system that uses focused solar radiation to produce steam, which is then used to run a turbine producing the electricity.


Solar thermal system:


Solar thermal power system use various techniques to focus sunlight to heat an inermediary fluid, known as heat transfer fluid that then is used to generate electricity. At present time there are three solar thermal power system currently being develpoed; parabolic throughs, power tower, and dish engine system. These techonologies involve thermal intermidary, they can be readily hybridized with fossil fuels and in some cases are adapted to utilize thermal storage. Hybridization and thermal storage can enhance the economic value of electricity.


Pakistan is located in a sunny belt and is likely to have extended sunshine hours and high insolution level. It is ideally located to take advantage of solar energy technologies. This energy source is widely distributed and abundently available in the country. The mean global radiation falling on horizontal surface is about 200-250 watt per day.


Balochistan is particularly rich in solar energy. It has an average global insulation of 19 to 20 MJ m2 per day with annual mean sunshine duration of 8 to 8.5 hours a day and these values are highest in the world.


Advantage of renweable energy resources:


One major advantage is the use of renewable energy resource is that it is sustainable and so will never run out. Renewable energy facilitate the less maintenance then traditional generators. Their fuels are derived from natural and available resources which reduce the cost of operation.


Even more importantly, renewable energy produce no or little waste products such as carbon dioxide and other chemical pollutants so has minimal impact on environment. Renewable energy products can also bring economic benefits to many regional areas, as most projects are located away from large urban centers and sub urban of capital cities. These economic benefits may be from increased use of local services as well as tourism.


Conclusion:


We believe that the promise of renewable energy resources has now become a reality. Both solar photovolatics and wind energy are experiencing rapid sales growth, decreasing capital cost and electricity generation cost while providing clean energy. Eventually, it is concluded that energy producers are in best position to capture renewable energy markets. These producers have capital needed to make forays into these markets, and most to lose if they do not invest and renewable energy technologiescontinue to flourish. It is believed that artful production of renewable energy technologies into energy production system along with encouragement of public sector.


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Published in: Volume 06 Issue 20

Short Link: http://www.technologytimes.pk/?p=13312