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Energy is the ability to do work.If there is no energy we won't be able to do any activity.Ex.Energy is required to cook food,to run car,buses,truck,train and use aeroplane. We use heat energy obtained by burning fuels like wood,LPG for cooking.Electricity is used for lighting bulbs and tubes,and to run radio,T.V etc.So energy is essential for our daily life.However,Sun is primary source of energy.view more....
A Good sources of energy is one of which can provide sufficient amount of energy in a convenient from over a long period of time.
Thus,useful energy=output energy-input energy
These sources of energy are those which are exhaustible and cannot be replaced once they have been used.
These sources have been accumulated in nature over a very long period of million of years.
> All these fuels are called fossil fuels
Renewable sources of energy are those which are inexhaustible,i.e.,which can be replaced as we use them and can be used to produce energy again and again.
These are available in an unlimited amount in nature and develop within a relativly short period of time.
The sources of energy which are commonly used and a major portion of our energy requirement are conventional sources of energy.The main conventional sources of energy are fossil fuels(coal,petroleum andnatural gases). As We discuss above.
Those sources which are not used extensively and which are tapped with the help of advanced technology are called alternative or Non-Conventional sources of energy. These sources are not based on the burning of fossil fuels.
The electricity produced from the kinetic energy of flowing water is called hydro-electric power and a plant which generates hydro-electric power is known as hydro-electric power plant.In this process,a high-rise dam is built to stop the flowing water.The kinetic energy of flowing water is converted into the potential energy of water stored behind the dam.
Wind power is the use of air flow through wind turbines to mechanically power generators for electric power. Wind power, as an alternative to burning fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, consumes no water, and uses little land. The net effects on the environment are far less problematic than those of nonrenewable power sources. Wind farms consist of many individual wind turbines which are connected to the electric power transmission network. Onshore wind is an inexpensive source of electric power, competitive with or in many places cheaper than coal or gas plants. Offshore wind is steadier and stronger than on land, and offshore farms have less visual impact, but construction and maintenance costs are considerably higher. Small onshore wind farms can feed some energy into the grid or provide electric power to isolated off-grid locations. Wind power gives variable power which is very consistent from year to year but which has significant variation over shorter time scales.It is therefore used in conjunction with other electric power sources to give a reliable supply. As the proportion of wind power in a region increases, a need to upgrade the grid, and a lowered ability to supplant conventional production can occur Power manage- ment techniques such as having excess capacity, geographically distributed turbines, dispatchable backing sources, sufficient hydroelectric power, exporting and importing power to neighboring areas, or reducing demand when wind production is low, can in many cases overcome these problems. In addition, weather forecasting permits the electric power network to be readied for the predictable variations in production that occur. As of 2015, Denmark generates 40% of its electric power from wind, and at least 83 other countries around the world are using wind power to supply their electric power grids.In 2014, global wind power capacity expanded 16% to 369,553 MW. Yearly wind energy production is also growing rapidly and has reached around 4% of worldwide electric power usage, 11.4% in the EU.
The main advantages include an unlimited, free, renewable resource (the wind itself), economic value, maintenance cost, and placement of wind harvesting facilities. First and foremost, wind is an unlimited, free, renewable resource. Wind is a natural occurrence and harvesting the kinetic energy of wind doesn't affect currents or wind cycles in any way. Next, harvesting wind power is a clean, non-polluting way to generate electricity. Unlike other types of power plants, it emits no air pollutants or greenhouse gases. The wind turbines harmlessly generate electricity from wind passing by. Wind energy is far more ecofriendly than the burning of fossil fuels for electricity. Currently, the United States, along with other countries, remains dependent on fossil fuels imported from unstable and unreliable nations. Strains on supply (of fossil fuels) are likely to increase the prices of fossil fuel resources and leave the US economy exposed to international market volatility. Wind power has the ability to free the US from the figurative economic bondage of fossil fuels. Once turbines and energy centers have been installed, the cost of maintaining turbines and generating wind power is next to nothing. Another advantage of wind power is the ability to place turbines wherever necessary. After performing research and finding areas that have adequate wind, experts may place the turbines in desired areas. These areas are usually unpopulated (offshore wind turbines, for example). In fact, offshore winds tend to blow harder and more uniformly than on land, providing the potential for increased electricity generation and smoother, steadier operation than land-based wind power systems. Fig. 1 shows offshore wind turbines harvesting energy.
Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. Biogas is a renewable energy source. Biogas can be produced by anaerobic digestion with anaerobic organisms, which digest material inside a closed system, or fermentation of biodegradable materials. Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulfide (H2S), moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat. Biogas can be compressed, the same way as natural gas is compressed to CNG, and used to power motor vehicles. In the UK, for example, biogas is estimated to have the potential to replace around 17% of vehicle fuel. It qualifies for renewable energy subsidies in some parts of the world. Biogas can be cleaned and upgraded to natural gas standards, when it becomes bio-methane. Biogas is considered to be a renewable resource because its production-and-use cycle is continuous, and it generates no net carbon dioxide. Organic material grows, is converted and used and then regrows in a continually repeating cycle. From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released when the material is ultimately converted to energy.
An unfortunate disadvantage of biogas today is that the systems used in the production of biogas are not efficient. There are no new technologies yet to simplify the process and make it abundant and low cost. This means large scale production to supply for a large population is still not possible. Although the biogas plants available today are able to meet some energy needs, many governments are not willing to invest in the sector.
Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis.It is an important source of renewable energy and its technologies are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light-dispersing properties, and designing spaces that naturally circulate air.The large magnitude of solar energy available makes it a highly appealing source of electricity. The United Nations Development Programme in its 2000 World EnergyAssessment found that the annual potential of solar energy was 1,575\9649,837 exajoules (EJ). This is several times larger than the total world energy consumption, which was 559.8 EJ in 2012.In 2011, the International Energy Agency said that "the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries\92 energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating global warming, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared".