We get electricity, which is a secondary energy source, from the conversion of
other sources of energy, like coal, natural gas, oil, nuclear power and other
natural sources, which are called primary sources. The same point there is with
acting principle of steam locomotive and engines.
Despite its negative
image, nuclear energy may be the most efficient and realistic means of meeting
the rapidly-growing demand for power. Why?
1)Thermal power plants generate
electricity by burning fossil fuels such as petroleum, coal and natural gas.
This combustion process is the source of CO2 emissions, which causes global
warming.Nuclear power generation, in contrast, harnesses the heat energy
produced by nuclear fission. Because there is no combustion involved in the
process, nuclear power generation does not emit CO2 in principle.
2)Furthermore, indirect CO2 emissions from processes such as
mining/transportation of fuels and development/operation of power stations are
miniscule. While a natural gas-fired combined cycle plant, which is the most
efficient power generation option, emits approximately 474g of CO2 to generate
1kWh of electricity, a nuclear power plant emits only about 20g of CO2 and can
generate the same amount of electricity.
3)For comparison, fossil-fuelled
power stations (and nuclear, for that matter) have an efficiency of about 33%.
In other words, about 1/3 of the heat energy released from the fuel gets turned
into electricity. The other 2/3 of the energy ends up as waste heat - it just
warms up the power station and its surrounding environment.
The maximum
theoretical thermal efficiency of a power station is around 64% (look up 'Carnot
Cycle'), but in real life the best thermal efficiency is around 42%. Various
other random heat losses eventually give you around 33% overall 'generation'
efficiency.
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