Chemistry - Efficiency of energy conversions
Efficiency of energy conversions
During an energy conversion, not all of the energy entering an energy
converter is transformed. The percentage that is transformed is known as
the efficiency of the energy transformation. We are mostly interested in
The conversion of chemical energy into electrical energy in a coal-fired
power station is approximately 30 to 40 per cent efficient.
The internal combustion engine used in most motor vehicles is
significantly less efficient than a coal-fired power station. Only about 20
per cent of the chemical energy in petrol is converted into mechanical
energy to drive the car. Most of the other 80 per cent is lost as heat.
The most efficient converters of chemical energy to electrical energy are
modern batteries and fuel cells, which can reach efficiencies as high as 70
to 90 per cent. This emphasises the benefits of of chemical energy to
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