Uses and Reliability of Energy Resources

The Three Uses of Energy Resources

Every time you switch on a light, take a bus, or turn up a radiator, you are relying on energy harvested from the Earth or the Sun.
Globally, we use energy resources for three main purposes: transport, heating, and electricity generation.
A Non-Renewable Energy Resource is a finite resource that is being used at a faster rate than it is replenished, meaning it will eventually run out (e.g., fossil fuels and nuclear).
A Renewable Energy Resource is being (or can be) replenished at a faster rate than it is used, meaning it will never run out (e.g., wind, solar, and biofuels).

Comparing Energy Resources for Transport

You might have noticed more cars plugging into chargers instead of filling up at petrol stations.
Historically, transport relied entirely on non-renewable fossil fuels, but there is an increasing shift toward renewable alternatives.

Transport Method	Non-Renewable Sources	Renewable Sources
Road Vehicles	Petrol and diesel (from crude oil); Natural gas (e.g., CNG buses).	biofuels (liquid bioethanol/biodiesel); Electricity (Electric Vehicles).
Trains	Coal (historical steam trains); Diesel.	Electricity (from renewable sources on the National Grid).
Aircraft	Kerosene (from crude oil).	Currently very limited; experimental biofuels.

When calculating the energy demands of transport, we look at the kinetic energy of the vehicles.
Formula: $E_k = \frac{1}{2} m v^2$

Worked Example:

Calculate the kinetic energy of a 1200 kg electric car travelling at 20 m/s.

Step 1: Identify values: $m = 1200\text{ kg}$ , $v = 20\text{ m/s}$ .
Step 2: Substitute into the equation: $E_k = 0.5 \times 1200 \times 20^2$
Step 3: Calculate the final answer: $E_k = 240,000\text{ J}$ (or $240\text{ kJ}$ ).

Comparing Energy Resources for Heating

Why does a hot water radiator stay warm long after the boiler turns off?
Heating buildings and water accounts for a massive portion of national energy use.
Historically, heating relied heavily on non-renewable resources, but there is an increasing use of renewable alternatives.

Heating Method	Non-Renewable Sources	Renewable Sources
Direct Heating (Fires/Stoves)	Coal (historically burned in fireplaces/stoves).	biofuels (plant matter or animal waste burned for heating).
Water and Space Heating	Natural gas (the most common UK resource, burned in boilers to heat water for radiators).	geothermal heat pumps (circulate water underground to extract thermal energy from hot rocks); solar heating panels (contain pipes of water heated directly by infrared radiation from the Sun).
Electric Heaters	Electricity (if generated from non-renewable sources on the National Grid).	Electricity (if generated from renewable sources on the National Grid).

Specific Heat Capacity is used to calculate the energy required by these heating systems: $\Delta E = m \times c \times \Delta\theta$ .

Comparing Energy Resources for Electricity Generation

Behind every plug socket is a complex chain of energy transfers starting at a power station.
The National Grid is supplied by a mix of non-renewable and renewable energy resources.

Electricity Generation Method	Non-Renewable Sources	Renewable Sources
Thermal (Heating water to turn a turbine)	fossil fuels (coal, oil, natural gas) burned to heat water; Nuclear fuel used to heat water via nuclear reactions.	biofuels (burned to heat water); Geothermal (hot rocks heat water to steam).
Kinetic (Directly turning a turbine)	None.	Wind (turns blades); Hydroelectric (falling water); Tides and Water waves (moving water).
Direct Electrical Conversion	None.	solar cells (photovoltaic cells transfer light directly into electricity without a turbine).

In most power stations, a fuel is used to turn a turbine, which then turns a generator to produce electricity.
Different resources have different energy transfers:
- fossil fuels: Chemical $\rightarrow$ Thermal (water/steam) $\rightarrow$ Kinetic (turbine) $\rightarrow$ Electrical.
- Nuclear: Nuclear store $\rightarrow$ Thermal $\rightarrow$ Kinetic $\rightarrow$ Electrical.
- Hydroelectric: Gravitational Potential Energy (water) $\rightarrow$ Kinetic $\rightarrow$ Electrical.
Power station efficiency is calculated using:

\text{Efficiency} = \frac{\text{Useful output energy transfer}}{\text{Total input energy transfer}} \times 100

Understanding Reliability and Environmental Impact

Imagine if your TV only worked when the wind was blowing outside.
A Reliable Energy Resource is one that can provide energy at any time to meet demand, independent of the weather.
fossil fuels, nuclear, biofuels, geothermal, and tides are reliable. Tides are considered reliable because they are completely predictable twice daily.
Wind, solar, and water waves are Intermittent (unpredictable and weather-dependent).
Environmental impacts vary drastically: burning fossil fuels releases Carbon Dioxide ( $CO_2$ ), which contributes to global warming, and Sulfur Dioxide ( $SO_2$ ), which causes acid rain.
biofuels are considered Carbon neutral because the $CO_2$ absorbed by the plants during growth equals the $CO_2$ released when they are burned.

Managing the National Grid: Base Load and Peak Demand

The National Grid must constantly balance the electricity generated with the electricity demanded by the country.
Base Load is the constant, minimum level of electricity demand required 24 hours a day. This is met by nuclear and coal power stations because they have long start-up times (nuclear takes up to 48 hours) and run efficiently continuously.
Peak Demand occurs during sudden increases in electricity usage. This is met by natural gas (which has a fast start-up time of about 30 minutes) and Pumped storage.
Pumped storage acts like a giant battery to manage demand. During low demand at night, surplus base load electricity pumps water up to a high reservoir (storing Gravitational Potential Energy).
During peak demand, the water is released through a turbine to generate electricity almost instantly.

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Get full access to revision notes, key terms, and exam tips for every subtopic.

Exam Tips

Common Mistake
Students often confuse solar cells with solar heating panels. Remember that solar cells generate electricity directly from light, whereas solar heating panels use infrared radiation to heat water.
2
When discussing the environmental impact of electric vehicles (EVs) in an exam, use the phrase 'zero emissions at the point of use' because the power station generating the electricity might still release greenhouse gases.
3
Never use the words 'green' or 'clean' to describe renewable energy. Instead, state specifically that they 'do not release greenhouse gases' or are 'carbon neutral'.
Common Mistake
Students often call tidal power 'unreliable' because tides go in and out. Examiners consider tidal power reliable because the tides are completely predictable.
5
When asked why gas power stations are used instead of coal or nuclear for sudden surges in demand, specifically state that gas power stations have a much faster start-up time.

Key Terms(20)

Non-Renewable Energy Resource: A finite resource that is used at a faster rate than it is replenished and will eventually run out.
Renewable Energy Resource: An energy source that is being (or can be) replenished at a faster rate than it is being used.
Reliable Energy Resource: An energy resource that can produce energy at any time on demand, independent of external factors like weather.
Intermittent: Energy resources that are available only some of the time and are usually weather-dependent, such as wind or solar.
Carbon neutral: A process where there is no net release of carbon dioxide into the atmosphere, such as burning biofuels.
Base Load: The constant minimum level of electricity demand over a 24-hour period.
Peak Demand: A period of high electricity usage that exceeds the base load, requiring fast-responding energy sources.
Pumped storage: A system that uses surplus electricity to pump water to a high reservoir, storing it as gravitational potential energy to be released during peak demand.
fossil fuels: Non-renewable energy resources, such as coal, oil, and natural gas, formed from the remains of ancient organisms.
geothermal heat pumps: Systems that circulate water underground to extract thermal energy from hot rocks, used to heat buildings directly.
solar heating panels: Devices containing pipes of water that are heated directly by infrared radiation from the Sun, used for heating water, not generating electricity.
solar cells: Devices that transfer light energy directly into electrical energy without the use of a turbine.
Specific Heat Capacity: The amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.
Carbon Dioxide: A greenhouse gas released when burning fossil fuels, which contributes to global warming and climate change.
Sulfur Dioxide: A gas released when burning certain fossil fuels (like coal and oil) that causes acid rain.
biofuels: Fuel produced from recently living organic matter, such as plant material or animal waste, which can be burned to produce energy.
turbine: A machine equipped with blades that is spun by the kinetic energy of a moving fluid (like steam, water, or wind) to turn a generator.
generator: A device consisting of a coil of wire in a magnetic field that converts kinetic energy into electrical energy.
efficiency: The ratio of useful output energy transfer to total input energy transfer, often expressed as a percentage.
infrared radiation: A type of electromagnetic radiation that transfers thermal energy, such as the heat radiated from the Sun.

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Key Terms(20)

Non-Renewable Energy Resource: A finite resource that is used at a faster rate than it is replenished and will eventually run out.
Renewable Energy Resource: An energy source that is being (or can be) replenished at a faster rate than it is being used.
Reliable Energy Resource: An energy resource that can produce energy at any time on demand, independent of external factors like weather.
Intermittent: Energy resources that are available only some of the time and are usually weather-dependent, such as wind or solar.
Carbon neutral: A process where there is no net release of carbon dioxide into the atmosphere, such as burning biofuels.
Base Load: The constant minimum level of electricity demand over a 24-hour period.
Peak Demand: A period of high electricity usage that exceeds the base load, requiring fast-responding energy sources.
Pumped storage: A system that uses surplus electricity to pump water to a high reservoir, storing it as gravitational potential energy to be released during peak demand.
fossil fuels: Non-renewable energy resources, such as coal, oil, and natural gas, formed from the remains of ancient organisms.
geothermal heat pumps: Systems that circulate water underground to extract thermal energy from hot rocks, used to heat buildings directly.
solar heating panels: Devices containing pipes of water that are heated directly by infrared radiation from the Sun, used for heating water, not generating electricity.
solar cells: Devices that transfer light energy directly into electrical energy without the use of a turbine.
Specific Heat Capacity: The amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.
Carbon Dioxide: A greenhouse gas released when burning fossil fuels, which contributes to global warming and climate change.
Sulfur Dioxide: A gas released when burning certain fossil fuels (like coal and oil) that causes acid rain.
biofuels: Fuel produced from recently living organic matter, such as plant material or animal waste, which can be burned to produce energy.
turbine: A machine equipped with blades that is spun by the kinetic energy of a moving fluid (like steam, water, or wind) to turn a generator.
generator: A device consisting of a coil of wire in a magnetic field that converts kinetic energy into electrical energy.
efficiency: The ratio of useful output energy transfer to total input energy transfer, often expressed as a percentage.
infrared radiation: A type of electromagnetic radiation that transfers thermal energy, such as the heat radiated from the Sun.

Uses and Reliability of Energy Resources

The Three Uses of Energy Resources

Every time you switch on a light, take a bus, or turn up a radiator, you are relying on energy harvested from the Earth or the Sun.
Globally, we use energy resources for three main purposes: transport, heating, and electricity generation.
A Non-Renewable Energy Resource is a finite resource that is being used at a faster rate than it is replenished, meaning it will eventually run out (e.g., fossil fuels and nuclear).
A Renewable Energy Resource is being (or can be) replenished at a faster rate than it is used, meaning it will never run out (e.g., wind, solar, and biofuels).

Comparing Energy Resources for Transport

You might have noticed more cars plugging into chargers instead of filling up at petrol stations.
Historically, transport relied entirely on non-renewable fossil fuels, but there is an increasing shift toward renewable alternatives.

Transport Method	Non-Renewable Sources	Renewable Sources
Road Vehicles	Petrol and diesel (from crude oil); Natural gas (e.g., CNG buses).	biofuels (liquid bioethanol/biodiesel); Electricity (Electric Vehicles).
Trains	Coal (historical steam trains); Diesel.	Electricity (from renewable sources on the National Grid).
Aircraft	Kerosene (from crude oil).	Currently very limited; experimental biofuels.

When calculating the energy demands of transport, we look at the kinetic energy of the vehicles.
Formula: $E_k = \frac{1}{2} m v^2$

Worked Example:

Calculate the kinetic energy of a 1200 kg electric car travelling at 20 m/s.

Step 1: Identify values: $m = 1200\text{ kg}$ , $v = 20\text{ m/s}$ .
Step 2: Substitute into the equation: $E_k = 0.5 \times 1200 \times 20^2$
Step 3: Calculate the final answer: $E_k = 240,000\text{ J}$ (or $240\text{ kJ}$ ).

Comparing Energy Resources for Heating

Why does a hot water radiator stay warm long after the boiler turns off?
Heating buildings and water accounts for a massive portion of national energy use.
Historically, heating relied heavily on non-renewable resources, but there is an increasing use of renewable alternatives.

Heating Method	Non-Renewable Sources	Renewable Sources
Direct Heating (Fires/Stoves)	Coal (historically burned in fireplaces/stoves).	biofuels (plant matter or animal waste burned for heating).
Water and Space Heating	Natural gas (the most common UK resource, burned in boilers to heat water for radiators).	geothermal heat pumps (circulate water underground to extract thermal energy from hot rocks); solar heating panels (contain pipes of water heated directly by infrared radiation from the Sun).
Electric Heaters	Electricity (if generated from non-renewable sources on the National Grid).	Electricity (if generated from renewable sources on the National Grid).

Specific Heat Capacity is used to calculate the energy required by these heating systems: $\Delta E = m \times c \times \Delta\theta$ .

Comparing Energy Resources for Electricity Generation

Behind every plug socket is a complex chain of energy transfers starting at a power station.
The National Grid is supplied by a mix of non-renewable and renewable energy resources.

Electricity Generation Method	Non-Renewable Sources	Renewable Sources
Thermal (Heating water to turn a turbine)	fossil fuels (coal, oil, natural gas) burned to heat water; Nuclear fuel used to heat water via nuclear reactions.	biofuels (burned to heat water); Geothermal (hot rocks heat water to steam).
Kinetic (Directly turning a turbine)	None.	Wind (turns blades); Hydroelectric (falling water); Tides and Water waves (moving water).
Direct Electrical Conversion	None.	solar cells (photovoltaic cells transfer light directly into electricity without a turbine).

In most power stations, a fuel is used to turn a turbine, which then turns a generator to produce electricity.
Different resources have different energy transfers:
- fossil fuels: Chemical $\rightarrow$ Thermal (water/steam) $\rightarrow$ Kinetic (turbine) $\rightarrow$ Electrical.
- Nuclear: Nuclear store $\rightarrow$ Thermal $\rightarrow$ Kinetic $\rightarrow$ Electrical.
- Hydroelectric: Gravitational Potential Energy (water) $\rightarrow$ Kinetic $\rightarrow$ Electrical.
Power station efficiency is calculated using:

\text{Efficiency} = \frac{\text{Useful output energy transfer}}{\text{Total input energy transfer}} \times 100

Understanding Reliability and Environmental Impact

Imagine if your TV only worked when the wind was blowing outside.
A Reliable Energy Resource is one that can provide energy at any time to meet demand, independent of the weather.
fossil fuels, nuclear, biofuels, geothermal, and tides are reliable. Tides are considered reliable because they are completely predictable twice daily.
Wind, solar, and water waves are Intermittent (unpredictable and weather-dependent).
Environmental impacts vary drastically: burning fossil fuels releases Carbon Dioxide ( $CO_2$ ), which contributes to global warming, and Sulfur Dioxide ( $SO_2$ ), which causes acid rain.
biofuels are considered Carbon neutral because the $CO_2$ absorbed by the plants during growth equals the $CO_2$ released when they are burned.

Managing the National Grid: Base Load and Peak Demand

The National Grid must constantly balance the electricity generated with the electricity demanded by the country.
Base Load is the constant, minimum level of electricity demand required 24 hours a day. This is met by nuclear and coal power stations because they have long start-up times (nuclear takes up to 48 hours) and run efficiently continuously.
Peak Demand occurs during sudden increases in electricity usage. This is met by natural gas (which has a fast start-up time of about 30 minutes) and Pumped storage.
Pumped storage acts like a giant battery to manage demand. During low demand at night, surplus base load electricity pumps water up to a high reservoir (storing Gravitational Potential Energy).
During peak demand, the water is released through a turbine to generate electricity almost instantly.

Sign up to continue reading

Get full access to revision notes, key terms, and exam tips for every subtopic.

Exam Tips

Common Mistake
Students often confuse solar cells with solar heating panels. Remember that solar cells generate electricity directly from light, whereas solar heating panels use infrared radiation to heat water.
2
When discussing the environmental impact of electric vehicles (EVs) in an exam, use the phrase 'zero emissions at the point of use' because the power station generating the electricity might still release greenhouse gases.
3
Never use the words 'green' or 'clean' to describe renewable energy. Instead, state specifically that they 'do not release greenhouse gases' or are 'carbon neutral'.
Common Mistake
Students often call tidal power 'unreliable' because tides go in and out. Examiners consider tidal power reliable because the tides are completely predictable.
5
When asked why gas power stations are used instead of coal or nuclear for sudden surges in demand, specifically state that gas power stations have a much faster start-up time.

Key Terms(20)

Non-Renewable Energy Resource: A finite resource that is used at a faster rate than it is replenished and will eventually run out.
Renewable Energy Resource: An energy source that is being (or can be) replenished at a faster rate than it is being used.
Reliable Energy Resource: An energy resource that can produce energy at any time on demand, independent of external factors like weather.
Intermittent: Energy resources that are available only some of the time and are usually weather-dependent, such as wind or solar.
Carbon neutral: A process where there is no net release of carbon dioxide into the atmosphere, such as burning biofuels.
Base Load: The constant minimum level of electricity demand over a 24-hour period.
Peak Demand: A period of high electricity usage that exceeds the base load, requiring fast-responding energy sources.
Pumped storage: A system that uses surplus electricity to pump water to a high reservoir, storing it as gravitational potential energy to be released during peak demand.
fossil fuels: Non-renewable energy resources, such as coal, oil, and natural gas, formed from the remains of ancient organisms.
geothermal heat pumps: Systems that circulate water underground to extract thermal energy from hot rocks, used to heat buildings directly.
solar heating panels: Devices containing pipes of water that are heated directly by infrared radiation from the Sun, used for heating water, not generating electricity.
solar cells: Devices that transfer light energy directly into electrical energy without the use of a turbine.
Specific Heat Capacity: The amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.
Carbon Dioxide: A greenhouse gas released when burning fossil fuels, which contributes to global warming and climate change.
Sulfur Dioxide: A gas released when burning certain fossil fuels (like coal and oil) that causes acid rain.
biofuels: Fuel produced from recently living organic matter, such as plant material or animal waste, which can be burned to produce energy.
turbine: A machine equipped with blades that is spun by the kinetic energy of a moving fluid (like steam, water, or wind) to turn a generator.
generator: A device consisting of a coil of wire in a magnetic field that converts kinetic energy into electrical energy.
efficiency: The ratio of useful output energy transfer to total input energy transfer, often expressed as a percentage.
infrared radiation: A type of electromagnetic radiation that transfers thermal energy, such as the heat radiated from the Sun.

Previous NoteTypes of Energy Resources Next NoteEnvironmental and Global Issues in Energy Use

Back to National and global energy resources

Put your knowledge into practice — try past paper questions for Physics

Key Terms(20)

Non-Renewable Energy Resource: A finite resource that is used at a faster rate than it is replenished and will eventually run out.
Renewable Energy Resource: An energy source that is being (or can be) replenished at a faster rate than it is being used.
Reliable Energy Resource: An energy resource that can produce energy at any time on demand, independent of external factors like weather.
Intermittent: Energy resources that are available only some of the time and are usually weather-dependent, such as wind or solar.
Carbon neutral: A process where there is no net release of carbon dioxide into the atmosphere, such as burning biofuels.
Base Load: The constant minimum level of electricity demand over a 24-hour period.
Peak Demand: A period of high electricity usage that exceeds the base load, requiring fast-responding energy sources.
Pumped storage: A system that uses surplus electricity to pump water to a high reservoir, storing it as gravitational potential energy to be released during peak demand.
fossil fuels: Non-renewable energy resources, such as coal, oil, and natural gas, formed from the remains of ancient organisms.
geothermal heat pumps: Systems that circulate water underground to extract thermal energy from hot rocks, used to heat buildings directly.
solar heating panels: Devices containing pipes of water that are heated directly by infrared radiation from the Sun, used for heating water, not generating electricity.
solar cells: Devices that transfer light energy directly into electrical energy without the use of a turbine.
Specific Heat Capacity: The amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.
Carbon Dioxide: A greenhouse gas released when burning fossil fuels, which contributes to global warming and climate change.
Sulfur Dioxide: A gas released when burning certain fossil fuels (like coal and oil) that causes acid rain.
biofuels: Fuel produced from recently living organic matter, such as plant material or animal waste, which can be burned to produce energy.
turbine: A machine equipped with blades that is spun by the kinetic energy of a moving fluid (like steam, water, or wind) to turn a generator.
generator: A device consisting of a coil of wire in a magnetic field that converts kinetic energy into electrical energy.
efficiency: The ratio of useful output energy transfer to total input energy transfer, often expressed as a percentage.
infrared radiation: A type of electromagnetic radiation that transfers thermal energy, such as the heat radiated from the Sun.