The law of conservation says that energy is neither created nor destroyed. When we use energy, it doesn’t disappear. We change it from one form of energy into another. A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy. Solar cells change radiant energy into electrical energy. Energy changes form, but the total amount of energy in the universe stays the same. Scientists at the Department of Energy think they have discovered a mysterious new form of energy called "dark energy" that is actually causing the universe to grow!
The simplest way to define energy is said by: the capacity to do work by moving matter against an opposing force. If neither the table nor pencil moves, no work is done and therefore no energy is transferred. Force and energy are just a physical definition in a model that eases 'understanding' of the world around us. With this model one can define many things like the conservation of energy , transferring of energy ,etc.
There are different kinds of energies like kinetic, thermal, heat, electrical, solar, potential and many more. These energies are transferred and obtained from different sources, which are namely classified as renewable and non renewable sources of energy.
It is recognized that non-conventional or alternative sources of supply will undoubtedly play an increasing role in development as growth proceeds. Virtually none of these sources, however, should be viewed as being free of environmental impacts; in fact, they may, in some cases, have significantly greater effect on the environment. From an energy perspective, the alternatives range from nuclear power through geothermal and biomass energy to solar, wind, tidal and hydropower. The importance of these alternative energy sources in the energy mix within the region and with respect to their environmental impacts is enormous.
With both energy and minerals, the technical opportunities for substituting non-conventional or alternative sources for conventional ones are significant. However, such substitutions are not taking place, nor are they expected to take place, on a large-scale through out the world.
Energy sources available in the world include coal, nuclear, hydroelectric, gas, wind, solar, refuse-based, and biomass. In addition, fusion had been originally proposed as the long-term source. Every form of energy generation has advantages and disadvantages as shown below.
Biogas is a mixture of methane (also known as marsh gas or natural gas, CH4) and carbon dioxide it is a renewable fuel produced from waste treatment. As methane is very hard to compress I see its best use as for stationary fuel, rather than mobile fuel. It takes a lot of energy to compress the gas (this energy is usually just wasted), plus you have the hazard of high pressure. Biogas in India is known as Gobar Gas which means Cow Dung Gas. This dung is collected, dried and sold as fuel for cooking (it burns slowly). Compressed Biogas can be stored as compressed gas but this is dangerous and cumbersome. Advantages to producing Biogas is it destroys methane, which is a highly destructive greenhouse gas, so it does not go into the atmosphere and contribute to global warming. It even provides clean-burning fuel for stoves and lamps instead of using wood or dung which lose their soil building and fertilizing value when burned; reduces labor, since women now spend one day a week to collect a backbreaking 60-80 lb. load of scarce wood; protects the remaining forests by reducing the need to gather firewood; reduces respiratory disorders caused by smoke from cooking with firewood which especially affects women and their small children; improves village hygiene, since the attached toilets lead to the pathogen-destroying digestion tanks of the systems; yield more potent fertilizer than the original constituent wastes like the dung collected by children at right; provide lighting...