Physics - fossil fuels and biomass + nuclear power Flashcards
Give three examples of non-renewable energy resources
coal crude oil and natural gas
Explain the step by step process in a fossil fuel power station, starting from when the fuel is burnt
fuel is burnt and the heat that is produced turns water to steam. This steam turns a turbine. The turbine spins a generator to produce electricity.
State three disadvantages of fossil fuels
burning releases pollutants
carbon dioxide contributes to global warming
the fuels need to be mined and transported which has a negative impact on the environment
State one advantages of fossil fuels
fossil fuel power plants are an established, reliable technology, producing large amounts of electricity
What is a biofuel?
biomass used for burning
Give examples of biofuels in solid form
wood, woodchips + straw, from specially grown trees or crops
Give examples of biofuels in liquid form
alcohol fuels (ethanol), produced by fermenting (conversion of sugar to carbon dioxide/alcohol by yeast) sugar cane crops
Give examples of biofuels in gas form
methane gas, from animal waste/manure, in storage tanks called sludge digesters/ rotting waste - food from homes
State three advantages of burning biomass
uses products that would otherwise be wasted
power stations can also supply hot water to local industry/houses
CARBON NEUTRAL
Explain what is meant by ‘carbon neutral’
burning biomass releases carbon dioxide. Unlike fossil fuels, there is no overall increase in carbon dioxide because the amount released is the same amount that was abosorbed by the plant when it was alive
State three disadvantages of burning biomass
releases atmospheric pollutants
in developing countries, land is used to grow crops for biofuels, which could otherwise be used for food, leading to food shortages
power plants are ugly to look at -> visual pollution
What happens in a nuclear reactor?
atoms of uranuum or plutonium undergo nuclear fission, which releases large amounts of heat energy. This heat is used to turn water to steam (much like in other thermal power plants). This steam drives turbines
What do nuclear reactors produce?
radioactive waste
State three advantages of nuclear power
large amounts of electricity can be generated for each kilogram of fuel used
fuel is rapidly available and won’t run out for thousands of years, unlike fossil fuels
no polluting gases are produced, like carbon dioxide, so there is no contribution to global warming/acid rain
State four disadvantages of nuclear power
produces radioactive waste which can be harmiful to living things
decommissioning (cost of building the plant and taking it down again when finished) is quite high, so electricity generated can be expensive
nuclear fuel requires processing before it an be used
nuclear reactors take a long time to increase/decrease the amount of electricity being generated because they have a very slow start up time
