Energy, water and environmental risks
Energy sources and their advantages and disadvantages, water supply and demand, and the environmental risks of economic development.
📌 Key points
- Non-renewable energy comes from finite sources that will run out: fossil fuels (coal, oil, natural gas) and nuclear power (uranium).
- Renewable energy comes from sources that will not run out: hydro-electric power (HEP), wind, solar, geothermal, tidal, wave, biofuels and fuelwood (if replanted).
- Burning fossil fuels releases carbon dioxide (a greenhouse gas) and sulfur dioxide, which can cause acid rain.
- Nuclear power produces very little carbon dioxide, but it is expensive and produces dangerous radioactive waste, and accidents are rare but serious.
- HEP needs a reliable water supply, deep narrow valleys and impermeable rock; dams can flood land and force people to move; geothermal power is used in volcanic areas such as Iceland.
- Many people in rural LICs depend on fuelwood, which can lead to deforestation.
- Water is used for agriculture (the largest user worldwide), industry and domestic purposes; supply comes from rivers, lakes, reservoirs, wells and boreholes from aquifers, and desalination.
- Water shortages are caused by low or unreliable rainfall, over-use of groundwater, pollution and growing demand; solutions include dams, water transfer schemes, recycling water and efficient irrigation such as drip irrigation.
- Environmental risks of economic development include soil erosion, desertification, deforestation, air and water pollution and the enhanced greenhouse effect, which causes global warming and rising sea levels.
- Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own needs.
📖 Key terms
- Non-renewable energy
- Energy from finite sources that will run out, such as coal, oil and gas.
- Renewable energy
- Energy from sources that are naturally replaced and will not run out, such as wind and solar.
- Hydro-electric power
- Electricity generated by running water turning turbines, usually at a dam.
- Aquifer
- Underground layer of permeable rock that stores water.
- Desalination
- Removing salt from sea water to make fresh water.
- Desertification
- The process by which land in dry areas becomes more like desert, caused by climate and human activity.
- Enhanced greenhouse effect
- Extra warming of the Earth caused by humans adding greenhouse gases to the atmosphere.
- Sustainable development
- Development that meets present needs without harming future generations' ability to meet theirs.
✏️ Worked example
A country produces 120 TWh of electricity a year: 54 TWh from gas, 30 TWh from coal, 24 TWh from HEP and 12 TWh from wind. Calculate the percentage from renewable sources.
- Identify renewable sources: HEP and wind (gas and coal are fossil fuels).
- Renewable total = 24 + 12 = 36 TWh.
- Percentage = 36 ÷ 120 × 100.
- 36 ÷ 120 = 0.3, and 0.3 × 100 = 30.
- Answer: 30% of the electricity comes from renewable sources.
For 'advantages and disadvantages' of an energy source, consider cost, reliability, environmental impact (pollution, CO2, landscape) and effects on people. Name a specific example where possible.
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