(3) Energy Resources
How can SO2 emissions be reduced?
Removing sulfur in fuel before burning it
Give 2 features of biofuels
Renewable Carbon-neutral
Define power stations
Sites which use fossil fuels, biofuels and nuclear fuels to generate electricity
What are the 2 types of solar panels?
Solar cell panels - generate electricity Solar heating panels - directly heat water
Define decommissioning
Taking stations out of use.
Give 3 features of wind power
Unreliable Renewable Carbon-free
Give 4 features of solar cell panels
Unreliable Renewable Carbon-free High installation cost
Give 5 features of wave power
Unreliable Unsightly Renewable Carbon-free Harmful to Environment (if tidal flow patterns change, the habitats of marine life and birds may be affected)
What fuels are used in nuclear power stations?
Uranium and Plutonium
How can CO2 emissions be reduced?
Using Carbon, Capture & Storage (CCS) technology (old oil and gas fields can be used for carbon dioxide storage)
What are capital costs estimated in (unit)?
cost per kilowatt of power
What percentage of solar energy absorbed do modern solar cells transfer into electricity
10%
How much power can a solar power tower generate in a hot, dry climate?
20+ MW; enough to power a few homes
How much energy does burning 1 kg of fossil fuel release?
30 million Joules
How many joules of energy does the average person use per second?
5000 Joules per second 150 thousand million Joules per year 10,000 kg of fuel per year as a result of inefficiencies
Define a wave generator
A device that uses waves to make a floating generator move up and down, turning the generator, generating electricity.
Define a carbon-neutral fuel
A fuel that does not result in a net increase in atmospheric greenhouse gases.
Define a renewable fuel
A fuel that is used up at the same rate that it is replaced (its biological source either regrows, or is continually produced)
Describe tidal power
A tidal power station traps water from each high tide behind a barrage, and releases it through turbines back into the sea, driving generators.
Define geothermal energy
Energy released by radioactive substances deep within the Earth heats the surrounding rock. Water is pumped down into these rocks which heat it into steam, driving electricity generators at ground level.
What would reduce the need for more power stations?
Energy saving schemes such as low-energy light bulbs and improved home insulation
At what time of the year is demand for electricity higher?
In winter
How is electricity from a wave generator delivered to the grid system?
It is delivered through a cable connecting the generator and the shoreline.
Describe how nuclear fuel is used in a nuclear power station
It is sealed in cans at the core of the reactor. When the nucleus of a uranium/plutonium atom undergoes fission, lots of energy is released. Energy transferred heats the core. A coolant, pumped through the core, transfers its energy. The coolant leaves the core hot, and flows to the heat exchanger, before returning to the core. The heat exchanger heats water into steam, which is used to drive turbines which turn electricity generators.
Compare the start-up time of different power stations
Longest to shortest: Nuclear Coal Oil Gas
Give an example of a biofuel? Where does it come from?
Methane. It can be collected from animal manure, sewage works and decaying rubbish.
Give 2 advantages of nuclear power
No greenhouse gases are produced Much more energy is transferred per unit kg fuel than other energy resources
What provides the base load of energy? What provides energy for daily variations?
Nuclear & coal-fired power stations provide a constant amount of electricity (the base load). Gas-fired power stations & pumped storage schemes meet daily variations/extra demand because of their fast start-up time.
Compare nuclear power with fossil fuel power
Nuclear power transfers 10,000 times more energy per kilogram than fossil fuel power (30 MJ; 300,000 MJ). Nuclear power produces radioactive waste that must be stored for many years; Fossil fuel power produces non-radioactive waste. Nuclear power produces no greenhouse gases; fossil fuel power does, as it is burned.
Give 3 features of geothermal energy
Reliable Renewable Carbon-free
When are solar cell panels useful?
When only small amounts of energy are needed (e.g. calculators) In remote places (e.g. small islands)
Describe how hydroelectric power can be generated
When rainwater collected in a reservoir (/water in a pumped storage scheme) flows downhill, it drives turbines, turning electricity generators. The water is pumped back up during off-peak hours
What 2 things does burning fossil fuels release?
Sulfur dioxide Carbon dioxide
Describe how electricity is generated from fossil fuels
The fossil fuels are burned, heating water in a boiler, producing steam. The steam is used to drive turbines which turn an electricity generator.
Give 6 disadvantages of renewable energy
They are currently not able to meet the world's demand. Wind turbines are noisy and unsightly. Tidal barrages affect the environment. Hydroelectric schemes often require habitats to be flooded. Solar cells must cover large areas to be useful. Some are unreliable.
Why are certain isotopes of Uranium and Plutonium used as nuclear fuels?
They are more unstable, thus, are more likely to undergo fission.
Describe why renewable energy resources are unreliable
They depend on: Hydroelectric: upland reservoir could run dry Wind/Waves: too weak on very calm days Tidal: height of tide varies on a monthly/yearly cycle Solar: none at night; variable during day
Give 4 advantages of renewable energy
They will never run out as they are constantly replenished by natural processes. They do not produce greenhouse gases/acid rain. They do not produce radioactive waste. They can be used where connection to the National Grid is uneconomical (e.g. in remote areas).
Describe a solar power tower
Thousands of flat mirrors (controlled by a computer, enabling them to track the Sun) are used to reflect sunlight onto a huge water tank at the top of a solar power tower. The water in the tank is heated into steam which is piped down to ground level, where it turns electricity generators.
Define biodiesel
A type of fuel which uses waste vegetable oil and plants such as rapeseed
Define a wind turbine
An electricity generator at the top of a narrow tower, whose turbine blades are driven by the force of the wind, turning a generator.
Define a biofuel
Any fuel taken from living/recently living organisms
State the percentage of each energy resource used to meet the global demand for energy around the world?
Coal - 31% Oil - 31% Gas - 24% Hydroelectricity - 7% Nuclear - 4% Other renewables - 3%
Which releases the most greenhouse gases when burned - oil, gas or coal?
Coal then oil then gas
What are running costs estimated in (unit)?
Cost per kilowatt hour of energy
Define Capital Costs
Costs needed to build, fuel, manage, decommission new energy facilities.
Where does most of the energy used come from?
From burning fossil fuels (mostly gas/oil/coal)
Where are fuels extracted from?
From underground or under the sea bed
Give 2 disadvantages of nuclear power
Produces radioactive waste which must be stored for many years. An explosion in a reactor could release radioactive material over a wide area, affecting the area and its inhabitants for many years.
Give 3 features of hydroelectric power
Reliable Renewable Carbon-free
