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Energy is the ability of a system (human,
mechanical etc) to do work. Practically all things on Earth require one
form of energy or the other to function as designed or desired. Humans,
animals, and mechanical/ electrical systems require energy inputs to
perform. Electricity, heating, and lighting for home and industrial uses
are all derived through energy.
Energy comes in different forms: kinetic,
mechanical, electrical etc. Energy can be transformed from one form to the
other. However, overall energy within a system is conserved i.e. does not
change - net energy lost balances net energy gained within the system.
There
are various forms of energy sources. Most sources are traceable to the
Sun. The traditional energy source, fossil fuels, received the initial
energy from the light used by plants for photosynthesis and animal
metabolic needs. Organic matters from the plant and animal remains later
turn into the fossil fuels (Coal, oil and natural gas) which are currently
widely in use for energy supply.
Some energy sources are renewable
while others are non-renewable.
Renewable energy sources are sources that are freely available and cannot
be easily depleted while the non-renewable sources can run out and are
often not freely available.
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