National & Global Energy Resources (AQA GCSE Physics): Revision Notes
Energy resources
What are energy resources?
Energy resources are sources we use to produce electricity, heat our homes, and power transport. There are two main types:
Renewable energy resources can be replaced as we use them. They will not run out.
Non-renewable energy resources cannot be replaced once we use them. They will eventually run out completely.
Understanding the difference between renewable and non-renewable energy sources is fundamental to modern energy policy and environmental science. This classification helps us evaluate the long-term sustainability of different energy options.
Renewable energy resources
Biomass
- What it is: Fuel made from living or recently living things like wood, animal waste, and sewage
- How it works: Burnt to release energy, or produces methane gas which can be used as fuel
- Key benefit: Carbon neutral - the carbon dioxide released when burnt equals the amount the organism took in while living
- Uses: Transport fuel, heating homes, generating electricity in power stations
Wind energy
- What it is: Uses moving air to generate electricity
- How it works: Wind turns the blades of wind turbines, which turn generators to make electrical energy
- Limitation: Only works when it's windy - not too little wind or too much wind
- Best locations: Windy areas like hilltops and coastal regions
Hydroelectricity
- What it is: Uses flowing water to generate electricity
- How it works: Water stored in a reservoir flows downhill through generators
- Key benefit: Generally very reliable
- Limitation: Won't work if the reservoir runs dry during droughts
Worked Example: How Hydroelectric Power Works
Step 1: Water is collected in a reservoir behind a dam Step 2: When electricity is needed, water flows through pipes down to generators Step 3: The flowing water turns turbines connected to generators Step 4: The generators convert the mechanical energy into electrical energy Step 5: Electricity is transmitted through power lines to homes and businesses
Geothermal energy
- What it is: Uses heat from inside the Earth
- How it works: Water is pumped down to hot rocks underground, returns as steam to turn generators
- Key benefit: Very reliable because the Earth's heat is constant
- Uses: Generating electricity, heating homes directly
Tidal power
- What it is: Uses the movement of sea water caused by tides
- How it works: Tidal streams flow through turbines to generate electricity
- Key benefit: Predictable - we know exactly when tides will occur
- Limitation: Only works in a few coastal locations with strong tides
Solar power
- What it is: Uses energy from the Sun
- How it works: Solar panels heat water for homes, or solar cells generate electricity directly
- Key benefit: Can provide energy to remote areas
- Limitation: Doesn't work when it's not sunny (at night or on cloudy days)
Wave power
- What it is: Uses the up and down movement of sea waves
- How it works: Wave motion turns generators to produce electricity
- Limitation: Unreliable - produces little energy on calm days with small waves
Non-renewable energy resources
Fossil fuels
- What they are: Coal, oil, and natural gas formed over millions of years
- How they work: Burnt in power stations to heat water into steam, which turns turbines
- Key benefit: Very reliable - work all the time
- Uses: Generating electricity, transport (petrol, diesel), heating homes
- Major problem: Produce carbon dioxide, which causes global warming
Climate Change Impact
Fossil fuels are the major contributor to climate change. When burnt, they release carbon dioxide that has been stored underground for millions of years, adding extra CO₂ to the atmosphere and causing global temperatures to rise.
Nuclear energy
- What it is: Uses uranium or plutonium atoms
- How it works: Nuclear fission releases huge amounts of energy to generate electricity
- Key benefit: Extremely reliable and produces about 10,000 times more energy per kilogramme than fossil fuels
- Major problem: Creates dangerous radioactive waste that stays harmful for thousands of years
Nuclear Waste Challenge
Radioactive waste from nuclear power plants remains dangerous for thousands of years and must be stored safely. This is one of the biggest challenges facing nuclear power today, as we need secure storage solutions that will last longer than human civilizations.
Key differences to remember
Understanding the trade-offs between different energy sources is crucial for making informed decisions about our energy future.
Renewable sources:
- Will never run out
- Usually better for the environment
- Can be unreliable (depend on weather conditions)
- Often more expensive to set up
Non-renewable sources:
- Will eventually run out
- Usually cause pollution or other problems
- Very reliable
- Often cheaper and easier to use
Key Points to Remember:
- Renewable energy can be replaced and won't run out - non-renewable energy will eventually run out
- Fossil fuels are reliable but cause global warming through carbon dioxide emissions
- Nuclear power produces huge amounts of energy but creates dangerous radioactive waste
- Weather-dependent renewables like wind and solar are unreliable but environmentally friendly
- Geothermal and tidal power are renewable and reliable, but only work in certain locations