P3- energy resources Flashcards
what are fossils fuels
Fossil fuels = coal, oil and gas
how are fossils fuels made?
Living organisms millions and millions of years ago died, and they became buried in the earth. Under a lot of heat and pressure, they became fossil fuels.
what happens when fossils fuels are burned
Fossil and nuclear fuels are non _______/_______
sustainable/renewable
what does non-renewable mean
Non-renewable = they can’t be replaced. This means we are using things faster than they are being made
how is energy generated in most coal/fossil powered station
In most gas/coal-fired stations (power plants), the fuel is burnt –> this heats water in a boiler –> this causes the water to become steam –> the steam rises to drive the turbine and turn the generator –> generates electricity
where can we get methane from
Methane is one of the gases we get from crude oil, HOWEVER there are also some natural sources of methane:
1) cow/animal manure
2) sewage works
3) decaying rubbish (landfill
what does Bio-fuel mean
Biofuel = fuel taken from living/recently living organisms
where does nuclear fuel take energy from
Nuclear fuel takes energy from atoms
what are 2 positives of bio-fuel
2 positives of biofuel: renewable and carbon neutral
what are the fuels in nuclear power stations
Fuel in nuclear power station = uranium or plutonium (radioactive isotopes so can be used as fuel)
why is uranium and plutonium radioactive
they are radioactive as the nucleus of the uranium atom is unstable, and so it can be split in two
what happens when there are lots of atoms in the core
When there are lots of atoms in the core it will get very hot
why is nuclear energy better than fossil fuels
Energy released by a kg nuclear fuel is 10,000x the energy released by a kg of fossil fuel
what are disadvantages of wind generator
DISADVANATGE: Unreliable - when there is little or no wind, no electricity is generated
how does wave energy work
Wave energy: waves make a floating generator move up and down –> motion turns the generator which generates electricity
disadvantage of wave energy
DISADV: 1. generators need to withstand storms and they don’t constant supply of energy
2. Requires a lot of maintenance and resources - lots of cables and buildings need to connect the generator to the grid
3. Visual pollution - spoils areas of coastline
what is ‘HEP’
HEP = Hydroelectric power
where is rain water collected?
Rainwater is collected in a resevoir (or water in a pumped storage scheme), which flows downhill
what drive the turbine and turns the generator in a reservoir
When this water is falling downwards, it drives the turbine which turns the generator
what can suns energy produce/generate
Sun’s energy can:
generate energy using solar cells
heats water directly in solar heating
why is solar energy not as useful for powering big things
Solar cells convert less than 10% of the energy they absorb into energy transferred by electricity
where are some example of where solar cells can be found
watches, calculators
why us sun energy not as reliable
Solar cells convert less than 10% of the energy they absorb into energy transferred by electricity
HOWEVER a LOT of solar energy is needed to create enough electricity to be useful
Unreliable where sun is often hidden behind the clouds
how does a solar cell work
A solar heating panel heats water that flows through it
Water in the tank is turned to steam by the heating effect of the solar radiation directed at the water tank
Steam is piped down to the generator where it makes electricity
what does geothermal energy mean
Geothermal energy:
geo = earth thermal=heat
how does geothermal energy produce energy
Geothermal energy –> uses energy released by radioactive substances deep within the earth
how does geothermal energy work
Power stations are built in volcanic areas or places where there are hot rocks underneath
Water is pumped down to these hot rocks –> heat turns the water to steam –> steam rises –> drives the turbines which turns the generator
what are fossil fuels and what are some examples
fossils fuels are the gases that get trapped in the earths atmosphere. For example, CO2, methane, water vapours
what causes climate change
Scientists believe the increase in greenhouse gases is the reason for global warming and climate change
why is burning fossil fuels bad?
Burning fossil fuel –> sulfur impurities in the fossil fuels means that when fossil fuels are burned, sulfur dioxide is released –> causes acid rain –> sulfur dioxide can be removed from the flue gases by lining the chimeny with calcium carbonate (limestone)
what are some advantages of nuclear energy
2 points
Advantages of nuclear energy:
1)No greenhouse gases/carbon emissions
2)Much more energy is transferred a kg of uranium or plutonium compared to a kg of fossil fuel
what are disadvantages of nuclear energy
Disadvantages:
1)Fuels rods have radioactive waste –> has to be stored safely for centuries
2)Nuclear reactions are normally safe but an explosion would release radioactive waste over wide area –> affects people for many years-eg. Chernobyl
3)Expensive
4)High maintenance
renewable sources advantages
4 points
Renewable Sources Adv:
1)Never runs out –> always being replenished by natural resources
2)Don’t produce greenhouse gases/carbon emissions or acid rain
3)No radioactive waste products
4)Can be used where connection to the national grid is uneconomical
renewable sources disadvantages
Not able to meet the world’s energy demands
Wind turbine - sound pollution
Tidal barrages affect habitats
HEP needs large resevoirs - affects habitats –> habitats are often flooded for dams
Solar cells need a large surface area to create a lot of electricity
Some are unreliable –> not available all the time
WHICH SEASON IS ENERGY DEMANDS HIGHEST
Energy demand is higher in winter than summer
why can renewable energy be unreliable
Renewable energy - very unreliable - very dependent on certain specific conditions - you can’t obtain energy on demand, the way it is required in winter
what is required to run a facility
Overall cost of new facility includes:
Capital costs to build - cost/kW of power
Capital costs to take it out of use
Running cost –> fuel + maintenance
Capital costs are lowest for gas-fired stations and highest for nuclear and wind
what are four demands that variable demands are met by
Variable demand is met by:
Nuclear and coal-fired stations to provide constant energy - base load demand
gas-fired stations and pumped storage schemes for daily and seasonal variations
Renewable energy for high demand when the conditions are right (windy for wind energy)
Renewable energy when low demand to store in pumped storage schemes
