Energy and the Environment

This lesson covers the environmental impact of energy use and how to approach evaluation questions about energy resources, as required by the Edexcel GCSE Physics specification (1PH0), Topic 3: Conservation of Energy. You need to understand global energy demand, climate change, and how to evaluate energy policies in exam questions.

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Global Energy Demand

The world's energy demand is increasing for several reasons:

• Population growth — more people need more energy for heating, transport, industry and electricity.
• Economic development — as countries become wealthier, energy use per person increases (more appliances, cars, industry).
• Technological development — new technologies (computers, data centres, electric vehicles) require energy.
• Urbanisation — more people living in cities increases demand for electricity and transport.

Key Statistics

Fact	Detail
Global energy demand	Increasing by about 1–2% per year
Main source of global energy	Fossil fuels (about 80% of total energy)
Fastest-growing energy source	Solar and wind (renewable)
UK electricity from renewables	About 40–45% (and rising)

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Climate Change and Fossil Fuels

Burning fossil fuels releases carbon dioxide (CO₂) into the atmosphere. CO₂ is a greenhouse gas — it absorbs and re-emits infrared radiation, trapping heat in the atmosphere.

The Enhanced Greenhouse Effect

1. Burning fossil fuels → releases extra CO₂ into the atmosphere.
2. Increased CO₂ → atmosphere absorbs and re-emits more infrared radiation.
3. More infrared radiation is directed back towards the Earth's surface.
4. Average global temperature increases — this is called global warming.
5. Global warming leads to climate change — changes in long-term weather patterns.

Effects of Climate Change

Effect	Detail
Rising sea levels	Thermal expansion of water and melting ice caps → coastal flooding
More extreme weather	More frequent and intense storms, droughts, heatwaves
Changes to ecosystems	Species cannot adapt quickly enough → loss of biodiversity
Agricultural impacts	Changed rainfall patterns affect crop yields
Ice cap melting	Loss of Arctic and Antarctic ice → habitat loss for polar species

Exam Tip: When discussing climate change, be precise. Say "burning fossil fuels increases CO₂ levels, which enhances the greenhouse effect, causing average global temperatures to rise." Do not just say "pollution causes climate change" — this is too vague and will not score full marks.

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Carbon Footprint

A carbon footprint is the total amount of greenhouse gases (mainly CO₂) released as a result of an activity, product, or process, measured in tonnes of CO₂ equivalent.

How to Reduce Carbon Footprint

Action	How It Reduces Carbon Footprint
Use renewable energy sources	No CO₂ emitted during generation
Improve energy efficiency	Less energy needed → less fuel burned
Insulate buildings	Less heating needed → less gas/electricity used
Use public transport or electric vehicles	Less CO₂ per person per journey
Plant trees	Trees absorb CO₂ from the atmosphere
Carbon capture and storage (CCS)	CO₂ from power stations is captured and stored underground
Reduce, reuse, recycle	Manufacturing produces CO₂ — reducing consumption lowers emissions

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Environmental Impact of Different Energy Sources

Comparing the Main Issues

Energy Source	CO₂ Emissions	Other Environmental Issues
Coal	Very high	Mining destroys habitats; produces SO₂ (acid rain) and particulates
Oil	High	Oil spills damage marine ecosystems; refining produces pollution
Natural gas	Moderate (about half of coal)	Fracking can cause earthquakes and water contamination
Nuclear	Very low (operation)	Radioactive waste; risk of accidents; mining uranium produces emissions
Wind	None (operation)	Visual pollution; noise; bird/bat deaths; manufacturing has a carbon cost
Solar	None (operation)	Large land area; manufacturing has a carbon cost; habitat disruption
Hydroelectric	None (operation)	Flooding valleys destroys habitats and displaces communities; affects fish migration
Tidal	None (operation)	Disrupts marine ecosystems; changes tidal patterns; very expensive
Wave	None (operation)	Visual impact; disrupts marine life; storm damage
Geothermal	Very low	Limited locations; drilling can cause small earthquakes; releases some trapped gases
Biomass	Low (carbon neutral*)	Land use for crops; deforestation risk; releases particulates when burned

Exam Tip: No energy source is perfect — every source has environmental impacts. Even renewable sources have impacts during manufacture, installation and decommissioning. A complete answer acknowledges this.

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Energy Security

Energy security means having a reliable, affordable supply of energy to meet demand.

Threats to Energy Security

Threat	Detail
Over-reliance on imports	If a country depends on foreign gas/oil, supply can be disrupted by political conflicts
Declining fossil fuel reserves	Oil, gas and coal will eventually run out
Increasing demand	If demand outpaces supply, prices rise and shortages occur
Intermittent renewables	Wind and solar cannot generate continuously

Improving Energy Security

• Diversify the energy mix — use a range of different sources.
• Develop renewable sources to reduce dependence on imported fossil fuels.
• Invest in energy storage (e.g., batteries, pumped hydro) to store excess renewable energy.
• Improve energy efficiency to reduce overall demand.
• Develop new nuclear power stations for reliable, low-carbon baseload electricity.
• Invest in research into new technologies (e.g., nuclear fusion, hydrogen fuel).

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Evaluating Energy Policies

In the exam, you may be asked to evaluate or discuss energy policies or the suitability of different energy resources. These questions are typically worth 6 marks and require a structured, balanced answer.

How to Approach "Evaluate" and "Discuss" Questions

1. Read the question carefully — identify what you are being asked to evaluate (a specific resource, a policy, or a comparison).

2. Give arguments FOR:

   • State specific advantages.
   • Use data or facts where possible.
   • Explain why each point matters.

3. Give arguments AGAINST:

   • State specific disadvantages.
   • Consider environmental, economic, and social factors.
   • Be specific — avoid vague statements.

4. Reach a conclusion:

   • Weigh up the arguments.
   • State your overall judgement.
   • Acknowledge trade-offs.

Example: "Evaluate the use of wind energy to generate electricity in the UK."

Arguments FOR:

• Wind energy produces no CO₂ during operation, so it helps the UK meet its climate change targets.
• Wind is a renewable resource — it will not run out.
• The UK has good wind conditions, especially offshore.
• Wind turbines have low running costs once installed.

Arguments AGAINST:

• Wind is intermittent — turbines do not generate when the wind is not blowing, so a backup source (e.g., gas) is needed.
• Wind turbines cause visual pollution — some people object to their appearance in the countryside.
• They can cause noise pollution and may harm birds and bats.
• The initial cost of building wind farms is high.
• Manufacturing and installing turbines has a carbon footprint.

Conclusion: Wind energy is a valuable part of the UK's energy mix because it helps reduce CO₂ emissions and does not rely on finite fuels. However, because it is intermittent, it cannot be the only source of electricity. A combination of wind with other renewables and a backup source provides the best balance of reliability and low environmental impact.

Exam Tip: In a 6-mark "evaluate" question, you need at least two points for and two points against, plus a conclusion. The quality of your explanation matters more than the number of points — explain why each advantage or disadvantage is important, rather than just listing them.

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Common Exam Question Formats