P3 - energy resources Flashcards
where does most of our energy come from
burning fossil fuels
how do coal or oil fired power stations work
burning fuel heats water in a boiler, this produces steam, the steam drives a turbine that turns an electricity generator
what is a biofuel
any fuel taken from living or recently living organisms
how is a biofuel renewable
it’s biological source either regrows or is continuously produced
how is a biofuel carbon neutral
the carbon the living organism takes in from the atmosphere can balance the amount that is released when it is burnt
what is the fuel used in a nuclear power at station
uranium
plutonium
how does a nuclear power station work
the uranium atoms nucleus splits in two, energy is transferred from nucleus, core becomes hot, energy of core is transferred by coolant, coolant flowed through pipe to heat exchanger then back to reactor core, energy transferred is used to turn water into steam which drives turbines
how does wind power work
wind drives turbines blades, this turns a generator, power generated increases as wind speed increases
how does wave power work
waves move a floating generator up and down, turns the generator
how does hydroelectric power work
rainwater collected in a reservoir flows down hill, flowing water drives turbines that turn electricity generators at the bottom of the hill
how does tidal power work
traps water from high tide behind barrage, water released into sea through turbines, turbines turn a generator
what is the physical distributor of all energy in UK
the national grid
when are solar panels useful
when only small amounts of electricity are needed
or in remote places
what are the disadvantages of solar panels
very expensive to buy (cost nothing to run though so every cloud)
lots are needed to generate enough power to be useful
how does a solar power tower work
thousands of mirrors reflect sunlight onto big water tank
water is turned to steam by heating effect of solar radiatiation
steak is piped to ground level where it turns electricity generators
how does geothermal energy work
energy is released by radioactive substances
energy transferred from these radioactive substances heat the surrounding rock
energy is transferred by heating towards the earths surface
what are the issues with fossil fuels
greenhouse gases get released, warming the atmosphere
produce sulfur dioxide which causes acid rain
non renewable
advantages of nuclear power
no greenhouse gases emitted
more energy is transferred from each kg of uranium/plutonium
disadvantages of nuclear power
used fuel rods contain radioactive waste which has to be stored safely for centuries
if a reactor explodes radioactive material would spread over a wide area
advantages of renewable energy sources
never run out
do not produce greenhouse gases
do not create radioactive waste
can be used where connection to national grid is uneconomical
disadvantages of renewable energy sources
not able to meet world demand for energy
wind turbines create a whining noise + are unsightly
tidal barrages affect habitats of creatures and plants
reservoirs for hydroelectric schemes can affect plant and animal life
solar cells need to cover large areas
unreliable
what are the reliability issues with hydroelectric, wind/waves, tidal, and solar power
hydroelectric - upland reservoirs could run dry
wind/waves - too weak on calm days
tidal - height of tide varies
solar - no solar energy at night, variable during day
how is the demand for electricity met (x4)
using nuclear and coal power stations to provide constant amount
gas fired power station and pumped storage schemes for daily variations in demand
using renewable sources when demand is high and when conditions are suitable
using renewable sources when demand is low to store energy is pumped storage schemes
what energy source is capital cost lowest for
gas fired power stations
what energy source is capital cost greatest for
wind power and nuclear power (including decommissioning cost)
what are overall costs lowest for
hydroelectricity
what are overall costs highest for
offshore wind farms
