LEARN · PRACTISE · DISCOVER
Energy Resources and Trade-offs
Almost everything we do uses energy: lighting homes, charging phones, growing food, making products and travelling. How we produce that energy affects the climate, air quality, landscapes, economies and national security. In this lesson you will compare the main energy sources and learn to evaluate the trade-offs involved, because every energy choice has benefits and costs.
Renewable and non-renewable
- Non-renewable resources form over millions of years or exist in limited amounts, so they can be used up on human timescales: coal, oil, natural gas and uranium.
- Renewable resources are naturally replenished on human timescales: sunlight, wind, flowing water, geothermal heat and sustainably managed biomass.
Fossil fuels
Coal, oil and natural gas formed from ancient plants and organisms. They have powered industrial societies for over two centuries and still supply a large share of the world’s energy.
| Advantages | Disadvantages |
|---|---|
| energy-dense and reliable | release CO2 when burned, driving climate change |
| existing infrastructure and supply chains | air pollution harms health |
| can produce power on demand | mining and drilling can damage land and water |
| finite supply; prices can swing sharply |
Natural gas produces less CO2 than coal when burned for electricity, but methane leaks during production and transport can reduce this advantage.
Nuclear power
Nuclear power plants use nuclear fission, splitting uranium atoms, to produce heat that generates electricity.
- Advantages: very low greenhouse gas emissions during operation, reliable output, small land footprint
- Disadvantages: high construction costs and long build times, radioactive waste that must be stored safely for very long periods, and public concern about rare but serious accidents
Countries make different choices about nuclear power, reflecting different views on cost, safety and climate priorities.
Renewable energy
| Source | How it works | Key advantage | Key challenge |
|---|---|---|---|
| Solar | panels convert sunlight into electricity | very low emissions; costs have fallen dramatically | output varies with daylight and weather |
| Wind | turbines turn in the wind to generate electricity | very low emissions; low running costs | variable output; visual and wildlife concerns |
| Hydropower | flowing water spins turbines | reliable and controllable | dams can flood land and disrupt rivers and fish |
| Geothermal | uses heat from inside Earth | steady output | only practical in certain locations |
| Biomass | burns plant material or converts it to fuel | can use waste materials | must be managed carefully to be low-carbon and avoid deforestation |
The variability challenge
Solar and wind power vary with weather and time of day. Solutions include energy storage such as batteries and pumped hydro, stronger electricity grids that move power across regions, demand flexibility (using more electricity when it is plentiful) and combining different sources.
The cheapest energy: efficiency
Energy efficiency means getting the same result using less energy. LED light bulbs use far less electricity than old incandescent bulbs for the same light. Insulating homes reduces heating and cooling needs. Efficiency often saves money and reduces emissions at the same time.
Example
A school spends a large part of its budget on electricity. An energy audit finds old lights, poorly insulated classrooms and computers left on overnight. Replacing lights with LEDs, adding insulation and switching off equipment cuts energy use significantly. The savings help pay for solar panels on the roof, further reducing costs and emissions.
Evaluating trade-offs
When comparing energy options, consider several criteria:
- Emissions: greenhouse gases and air pollution
- Cost: building, running and maintaining
- Reliability: can it supply energy when needed?
- Land and water use
- Local impacts: jobs, wildlife, landscapes and communities
- Energy security: dependence on imports
No single source is perfect on every criterion. Most energy experts expect a mix of sources, with the balance depending on each country’s resources and priorities.
Energy access and fairness
Hundreds of millions of people, mostly in parts of sub-Saharan Africa and South Asia, still lack reliable electricity, according to the International Energy Agency. For these communities, expanding energy access is essential for health, education and economic opportunity. Off-grid solar systems and small local grids have brought electricity to many rural homes for the first time. Energy decisions therefore involve fairness as well as environmental impact. Balancing access, cost and emissions is one of the central challenges of the coming decades.
Key takeaways
- Non-renewable sources can be used up; renewable sources are naturally replenished.
- Fossil fuels are reliable but drive climate change and air pollution.
- Nuclear is low-carbon but faces cost and waste challenges; renewables are low-carbon but variable.
- Efficiency is often the cheapest option, and energy choices involve weighing multiple trade-offs.
Practice
1. Classify as renewable or non-renewable: wind, coal, solar, uranium, geothermal. 2. Give one advantage and one challenge of solar power. 3. Name two ways to deal with the variability of wind and solar power.
Answers: 1 wind, solar and geothermal are renewable; coal and uranium are non-renewable. 2 advantage: very low emissions or falling costs; challenge: output varies with daylight and weather. 3 any two of: batteries or other storage, stronger grids, demand flexibility, or combining different sources.