A renewable energy resource is one that is being (or can be) replenished as it is used.
A reliable resource is one which can always be used. Fossil Fuels are reliable. The Sun is unreliable.
The uses of energy resources include: transport, electricity generation and heating.
The main energy resources available for use on Earth include:
Fossil Fuels (Coal, Oil, Natural Gas)
- Fossil fuels take millions of years to form from the fossilised remains of trees and plants
- Non-renewable
- Used for transport, electricity generation and heating
- Reliable
- Burning fossil fuels releases greenhouse gases which contribute to global warming. Burning coal releases nitrogen oxides which dissolve in water to form acid rain.
Nuclear Fuel
- Uses metals like Uranium and Plutonium which can be made to undergo the nuclear fission process
- Non-renewable
- Used for transport (there are some submarines which use nuclear power) and electricity generation
- Reliable; the power stations can not be turned on quickly so they stay active once they are switched on.
- The radioactive waste must be stored safely to avoid contaminating the environment, people or wildlife.
Biofuel
- Bioethanol is an alcohol made from crops. Biofuel can also be plant or farm waste which is burned.
- Renewable
- Used for transport, and heating
- Reliable
- Burning biofuel releases greenhouse gases which contribute to global warming. Land that is being used to grow the crops used to produce biofuel reduces the land available to grow food.
Wind
- Kinetic energy of the wind is used to turn a turbine which turns a generator to produce electricity
- Renewable
- Used for transport (sail boats), and electricity generation
- Non-reliable (the wind may not be blowing)
- Releases greenhouse gases. Wind turbines are noisy and some believe unsightly.
Hydroelectricity
- Water is collected high up behind a dam. When the waters released the kinetic energy of the falling water is used to generate electricity.
- Renewable
- Used for electricity generation
- Reliable; also is used when demand peaks suddenly as the electricity generation starts very quickly
- The dam and flooding behind it destroys habitats
Geothermal
- When hot rocks are near the surface of the Earth, the heat can be used to turn water to steam which is used to generate electricity
- Renewable
- Used for electricity generation
- Reliable if there are hot rocks near the surface
The Tides
- When the tide flows in and out twice a day, the kinetic energy of the water is used to generate electricity
- Renewable
- Used for electricity generation
- Not reliable as the tide only happens twice a day
- The equipment used can prevent migration of water life and stop boats from moving freely
Water Waves
- The kinetic energy of the waves is used to generate electricity
- Renewable
- Used for electricity generation
- Reliable
- The ocean is a difficult environment for equipment to be positioned in. The equipment can cause problems for boats.
The Sun
- The sun can be used to generate electricity using PV (photovoltaic) cells or be used to heat water.
- Renewable
- Used for electricity generation, and heating
- Not reliable; the sun does not always shine and the hours of daylight vary across the seasons.
- The land taken up for PV cells would otherwise have been used to grow crops.
Question: Describe the environmental advantages and disadvantages of using wind turbines to generate electricity in the UK. (4 marks)
- Environmental Advantages
- renewable / sustainable (energy source)
- conserves fossil fuels
- no release of pollutant gases e.g. sulfur dioxide
- no release of greenhouse gases allow does not release carbon dioxide
- does not contribute to global warming
- Environmental Disadvantages
- noise pollution
- visual pollution
- bird kill
- not always windy so more use of fossil fuel power stations
Question: Give one advantage and one disadvantage of using nuclear power stations rather than gas-fired power stations to generate electricity. (2 marks)
- Advantage
- produce no / little greenhouse gases / carbon dioxide
- high(er) energy density in fuel
- long(er) operating life
- Disadvantage
- produce (long term) radioactive waste
- accidents at nuclear power stations may have far reaching or long term consequences
- high(er) decommissioning costs
- long(er) start up time
Question: Explain one effect that burning fossil fuels has on the environment. (2 marks)
- produces carbon dioxide / nitrogen oxides
- that (may) contribute to global warming
Electricity Demand
There are times across a day that we use more electricity; the demand for electricity varies.
We might used more electricity:
- When we get home from school and put the TV/toaster/kettle on
- In the morning when we have just woken up and need to use lights & heating
- In the winter when it gets dark earlier
