|On this page: Forms of energy | Renewable | Non-renewable | Alternative|
Energy and Power
ENERGY is the capability of doing work.
ENERGY UNITS are kilocalories (kcal), Kilowatthours (kWh) of electricity, British thermal units (Btu), Joules (J), etc.
ENERGY EQUIVALENTS are barrels of petroleum, Quads, tons of bitumous coal, cubic meters of natural gas, etc.
POWER is the (potential) speed of work, i.e. the (capacity to) work per unit of time. Power can also be defined as the rate of energy transfer.
POWER UNITS are Watt (W), British Horspower (BHP), Pferdestärke (PS), etc.
POWER USE Power is the amount of energy used over a period of time.
Forms of energy
Also compare: Energy Synopsis
There are several forms of energy, such as
- solar: the sun - the source of most energy on the surface of the Earth
- geothermal: warmth from hot water wells and geysirs
- human and animal energy
(A suffient diet provides an adult human with some 2500 kilocalories per day. Approx. 1600 kcal energy is needed for maintaining our body and life functions. The remainder of some 900 kcal is vailable for performing "work", which includes walking, climbing stairs, work in the household and on the farm, or in a factory or office. This work energy per day is about the same as 1 kilowatthour (1 kWh). A kilowatthour is the energy consumed by a 100 Watt lightbulb that burns for 10 hours (1 kW is 1000 Watt)
- biological (foodstuffs, including cereals, vegetables, meat, fish, etc., wood, cow dung, etc.)
- motion (= kinetic) (wind, water, a rotating flywheel, a motorcar at a certain speed)
- fossil fuels (coal, oil, natural gas, uranium),
- chemical (a battery, a fuel cell, explosives)
- electrical (factually a form of motion energy - the motion of electrons, mostly produced by the motion of a turbine, which in turn is driven by steam, water, or wind)
If the energy is stored, e.g. in coal or in fat or in potatoes, it can be either used or saved for later. Motion energy can be stored, e.g. by pumping water to a higher level dam.
Renewable Energy [top]
Bio (plants and trees, animal, human), wind, water, solar
Non-Renewable Energy [top]
Oil, petrol, gas, nuclear
Alternative Energy [top]
Fuel cells, Hydrogen, biogas
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