P3 - Sustainable energy Flashcards
What are the 6 types of primary energy sources?
- Fossil fuels (coal, oil, gas)
- Nuclear fuel (uranium and plutonium)
- Biofuels (plants and animals)
- Wind
- Waves
- Sunlight (radiation from the Sun)
What can primary energy sources transfer their energy to?
Secondary energy sources, e.g. electricity
Why is electricity a secondary energy source?
It is produced using other energy sources.
What are fossils fuels known as?
Non-renewable energy source (one day they will run out)
What does the burning of fossil fuels increase?
The amount of Carbon Dioxide which is a greenhouse gas
What does the Greenhouse Effect (caused by CO2) contribute to?
GLOBAL WARMING: an increase in the temperature of the Earth’s surface
What does global warming result in?
Climate Change - leading to floods and storms
What is Power?
The amount of energy transferred in one second
i.e. the rate of energy transfer
A power of one Watt (W) transfers…?
One JOULE of energy in one second.
How do you calculate the transfer of energy?
Energy transferred (J / kWh) = Power (W / kW) x Time (s/h) E = P x t
Why does Domestic electricity measure energy in transfer in kilowatt-hours (kWh) rather than Joules (J)?
A joule is a very small amount of energy.
It would be ridiculous to write down large numbers in Joules.
What is Current?
What is current measured in?
The flow of electricity in a circuit.
It’s measured in AMPERES.
What is Voltage of a power supply measured in?
Volts (V)
What does ELECTRIC current in an appliance do?
Transfers energy to it from the power supply.
What is the equation for calculating Electrical power?
Electrical power (W) = Current (A) x Voltage (V)
What is the power of an electrical device the rate of?
How is this normally given as?
The rate at which it transfers energy from the power supply.
This is normally given as a rating.
What is the formula for APPLIANCE current?
Appliance current (A) = Appliance power (W) / Supply voltage (V)
What does current in a COMPONENT transfer?
Electrical Energy into other useful forms
What does current in the connecting wires transfer?
It WASTEFULLY transfers electrical energy to heat.
What is the formula to calculate the electricity supplied to a component?
Electricity supplied to a component (in Units) = Power (kW) x Time (hrs)
What is for the formula to calculate the cost of electricity?
Cost of electricity = number of units supplied x cost per unit
What are 3 ways in which information about energy use can be displayed?
- a PIE CHART to compare different uses of electricity
- a BAR CHART to show the amount of electricity used by different components
- a LINE GRAPH to show how the number of units consumed changes with time.
What do Sankey Diagrams show?
The energy transfers in a component.
The sum of the energy transfers OUT of a component equals the….
What does this statement show?
The sum of the energy transfers OUT of a component equals the INPUT ENERGY.
This statement shows that energy is CONSERVED.
The amount of energy input in a Sankey Diagram is shown at the…
…LEFT of the arrow tail and is proportional to the thickness of the arrow tail.
The sum of the widths of the NEW arrows at a split is equal to the…
width of the arrow BEFORE the split.
Each energy OUTPUT should be shown on the…
RIGHT with an arrow head.
Useful energy transfers in a Sankey Diagram flow to the…
Wasteful energy transfers flow….
Useful energy transfers in a Sankey Diagram flow to the RIGHT.
Wasteful energy transfers flow DOWN or UP.
What does the efficiency of a component tell you?
The proportion of electricity that it transfers to a useful form.
What is the equation for Efficiency?
energy USEFUL transferred / TOTAL energy supplied x 100%
As a person, how can we use less electricity? Give 5 ways.
- Using high-efficiency A-rated appliances
- Using energy-saving lightbulbs.
- Turning off components when they aren’t needed.
- Not boiling more water than is necessary and cooking food in a microwave oven.
- Installing cavity wall / loft-insulation / double glazing / fibreglass wool hot water tank jacket / thick curtains/ in houses to reduce heat loss.
As a nation, how can we use less energy? Give 3 ways.
- Using more efficient cars.
- Living in houses with better installation.
- Building more efficient power stations and improving the output of old power stations.
How can workplaces save energy? Give 3 ways.
- Appliances should be switched off when not in use.
- Not printing and photocopying things unnecessarily.
- Providing employees incentives for using energy-efficient ways to travel to work, e.g. cycling/public transport.
How can the government encourage people to save energy? Give 3 ways.
- Offering grants for better home installation.
- Running schemes to trade in old boilers for more efficient ones.
- Improving public transport.
As the population increases and the quality of life for many people improves, what will rise in the future?
The global demand for energy and other resources.
How can the impact of human activity on the environment be reduced? Give 2 ways.
- Recycling resources such as metals, glass and plastics.
2. Generating electricity from renewable sources of energy, e.g. water, wind and solar power.
Why is electricity convenient?
It is easily transmitted over long distances and can be used in many ways.
What device is used to produce mains electricity?
GENERATORS
What happens in a generator?
It contains an ELECTROMAGNET near a coil of wire. There is a voltage across the coil when the electromagnet spins.
What type of energy transfer happens in generators?
Generators use ELECTROMAGNETIC INDUCTION to turn Kinetic Energy from the turbines in power station to mains electricity.
If you want a bigger voltage and current in the wire, you can…
turn the magnet faster.
The bigger the current and voltage, in a generator, the…
more fuel we use up every second.
What does the turbine do?
Spins the shaft of the generator to make electricity.
How is a turbine set spinning?
By steam, hot exhaust gas, wind and water.
What do thermal power stations use to spin the turbine from high pressure steam.
Primary energy sources, e.g. coal, oil, gas, and nuclear.
How do coal-fired power stations spin the turbine?
By burning coal to transfer energy into water.
How do gas-fired power stations spin the turbine?
By burning natural gas to make hot gas for a turbine - another turbine is spun by steam from water heated by the hot gas.
How hydroelectric power stations spin the turbine?
By using a jet of high pressure water at the base of a dam.
How do wind-driven power stations spin the turbine?
By using convection currents in the atmosphere caused by the heating effect of the Sun on the land.
What are the 5 processes in a coal/oil/thermal power stations?
- Coal/oil burnt in furnace
- Water heated to produce steam
- Jet of steam turns a turbine
- Turbine spins the generator
- Electricity produced by generator
How do nuclear power stations make high pressure steam?
- Putting fuel rods close to each other in the REACTOR so that they heat up.
- Taking away the heat with high pressure water circulating around the rods.
- Using the high pressure water to boil low pressure water in a boiler.
What do nuclear power stations produce?
RADIOACTIVE WASTE. This a serious health risk.
What does nuclear waste emit?
IONISING RADIATION, which affects body cells.
What is IRRADIATION?
Being exposed to radiation WITHOUT coming into contact with the source. As soon as you leave the irradiated area, the damage to the body stops.
What is CONTAMINATION?
When something gets MIXED UP with radioactive material, e.g. drinking contaminated water / breathing / getting it on skin, etc. You still be exposed to the radiation once you’ve left the area.
Why is contamination a more serious hazard than irradiation? Give 3 reasons.
- It can result in a longer exposure to radiation.
- It is difficult to remove the radioactive material.
- It is difficult to stop the radioactive material from spreading through the environment.
Why do we often overestimate the risk from ionising radiation? Give 3 reasons.
- It cannot be seen or felt.
- Its effects take a long time to develop.
- People worry about unfamiliar technology.
What can stastiscs about death rates can be used for?
Give 3 uses.
- To compare risks from different technologies.
- Decide which technologies need to be controlled.
- Decide which risks are too small to worry about.
What are 3 renewable energy sources that can spin turbines directly to produce electricity?
- Hydroelectric
- Wind turbines
- Wave technology
What is The National Grid?
A network of cables which carries electricity throughout the UK.
Why do power cables warm up?
They wastefully transfer electrical current to thermal energy.
What does increasing the voltage of a power cable result in?
REDUCES the current.
Why does the National Grid carry electricity at a very high voltage?
To reduce wasteful energy transfers in the cables.
What structure connects to the National Grid to reduce the voltage to our homes?
Substations
The mains supply voltage to our homes is ____ volts.
230V
What are 4 energy sources that can produce large amounts of electricity?
- Fossil fuels
- Nuclear power
- Hydroelectricity
- Biofuels
What are 3 energy sources that rely on the right sort of weather?
- Wind
- Waves
- Solar
What do fossil fuels do that impact the environment?
They produce greenhouse gases ; extracting them is dangerous and a pollution risk.
What does nuclear power do that impacts the environment?
Creates radioactive waste.
What do wind farms do that impact the environment?
It can cause noise and visual pollution.
What do hydroelectric and tidal dams do that impact the environment?
They flood large areas.
When choosing an energy source, what are 6 factors to consider?
- Its impact on the environment.
- The cost of building and running the power station.
- How much carbon dioxide and other waste it produces.
- The reliability of the energy source.
- The cost of using the energy source.
- The efficiency of the transfer of energy to electricity.
What is the power output of a power station measured in?
Millions of watts or MEGAWATTS (MW)
What is the output of a power station which uses nuclear or fossil fuel?
100 MW
What is the lifetime of a power station which uses nuclear or fossil fuel?
40 years
What is the power output of a wind farm?
300 MW - but this varies with the weather.
What is the lifetime of a wind farm?
20 years
What is the power output of a hydroelectric power station?
10 000 MW
What is the lifetime of a hydroelectric power station?
80 years
What are 4 advantages of fossil fuels?
- They produce a lot of energy
- Relatively cheap
- They do not rely on the weather.
- We have lots of fossil fuel power stations so we don’t need to spend money on new technology to carry on using them.
What are 4 disadvantages of fossil fuels?
- They release CO2, a greenhouse gas (causes global warming and climate change).
- Burning coal and oil also releases SULFUR DIOXIDE (causes acid rain and can harm trees and soils)
- Coal mining makes a MESS of the landscape, especially “open-cast mining”.
- Oil spillages cause serious environmental problems.
What are 3 advantages of Nuclear Power?
- Releases A LOT MORE ENERGY than chemical reactions (like burning).
- A nuclear power station DOESN’T PRODUCE CO2 when making electricity.
- Nuclear fuel (e.g. uranium) is relatively CHEAP.
What are 5 disadvantages of Nuclear Power?
- Produces radioactive waste (causes cancer and harms the surrounding environment).
- Requires EXTRA SAFETY PRECAUTIONS.
- People who live close are often more scared of the risks.
- Nuclear power stations take the LONGEST TIME of all the power stations to start up.
- The overall COST of nuclear power is HIGH due to the cost of the power plant and final decommissioning.
What are 3 advantages of biofuels?
- Renewable
- Relatively quick source of energy
- CARBON NEUTRAL
What are 2 disadvantages of biofuels?
- Forest has been cleared to make room to grow biofuels (causes loss of natural habitats).
- The decay and burning of this vegetation also increases CO2 and METHANE emissions.
What are 3 advantages of solar energy?
- No pollution (although they do use quite a lot of energy to manufacture in the first place)
- In sunny countries solar power is a very reliable source - but only in the DAYTIME.
- The energy is free and running costs are almost nil (after the initial costs).
What are 5 disadvantages of solar energy?
- Initial costs are high.
- Generates electricity on a relatively small scale.
- It may benefit some parts of the world better than others and it is not effective at night time.
- Ugly-looking
- Often not practical / too expensive to connect them to the National Grid.
What are 4 advantages of wind energy?
- Electricity is generated directly from the turbines.
- No pollution (except when manufactured)
- No fuel costs and minimal running costs.
- No permanent damage to the landscape.
What are 4 disadvantages of wind energy?
- Spoils the view
- Very noisy
- No power if the wind stops - impossible to increase supply when there’s extra demand.
- Initial costs are quite high
What are 3 advantages of wave power?
- No pollution
- No fuel costs and minimal running costs
- Very useful for small islands
What are 5 disadvantages of wave power?
- Fairly unreliable - waves tend to die out when the wind drops.
- Initial costs are high
- Wave power is never likely to provide energy on a large scale
- Spoils the view
- Hazard to boats
What are 5 advantages of tidal power?
- No pollution
- Reliable
- Excellent for storing energy ready for periods of peak demand.
- No fuel costs and minimal running costs.
- Has the potential for generating a significant amount of energy.
What are 6 disadvantages of tidal power?
- Prevents free access by boats
- Spoils the view
- Alters the habitat of wildlife
- The height of the tide is variable (lower tides = less energy)
- Initial costs are moderately high
- Can only be used in some of the most suitable estuaries
What are 3 advantages of hydroelectricity?
- No pollution
- Immediate response to increased demand
- Fairly reliable except in times of drought
What are 2 disadvantages of hydroelectricity?
- Big impact on the environment - rotting vegetation releases methane and CO2, some species lose their habitats, reservoirs can also look very unsightly when they dry up.
- Initial costs are high
What is 1 disadvantage of geothermal energy?
Brilliant free, renewable energy with NO REAL ENVIRONMENTAL problems.
What are 3 disadvantages of geothermal energy?
- Only possible where hot rocks lie quite near to the surface.
- The cost of drilling down several km to the hot rocks.
- Very few places where this seems to be an economic option.
What does a secure energy supply in the future require us to do? Give 5 ways.
- Generate enough electricity to avoid power cuts.
- Have constant access to energy sources
- Replace old power stations with more efficient ones.
- Use a mix of renewable energy sources
- Use more renewable energy sources as fossil fuels run out?
