VMBO Year 3 · Sustainable living · Section 7.4
Energy
Where does our energy come from?
People use energy for heating, transport and electrical appliances. The sources studied here fall into three broad groups: fossil fuels, nuclear energy and renewable energy. Each has advantages, environmental impacts and practical limitations.
Fossil fuels
Natural gas, oil and coal formed over millions of years from ancient organic material. Burning them releases energy and carbon dioxide, and can also release harmful air pollutants. They are energy-dense and existing systems make them convenient to store, transport and use. However, their supply is finite, prices vary and their greenhouse-gas emissions contribute to climate change.
Nuclear energy
Nuclear fission splits atomic nuclei, releasing energy used to generate electricity. Electricity production has low operational carbon emissions, although mining, construction and other stages still have impacts. Nuclear power produces radioactive waste requiring long-term management, and serious accidents can release radioactive material. Uranium is also a finite resource.
Renewable and sustainable energy
Renewable sources are replenished naturally on human timescales. They can reduce reliance on fossil fuels, but renewable does not mean impact-free. Electricity from renewable sources is often called green electricity, while fossil-fuel electricity is sometimes called grey electricity. Sustainability depends on the whole system and its environmental and social effects.
Examples
- Solar energy: sunlight converted into electricity by solar panels or used for heating.
- Wind energy: moving air driving wind turbines.
- Hydropower: energy from flowing or falling water.
- Tidal energy: energy from tides and tidal currents.
- Biomass: organic material used as an energy source.
- Biofuels: fuels made from biomass.
Sun and wind are not available at a constant rate, so electricity systems need flexibility, storage or other balancing sources. Biomass can be replenished, but its sustainability depends on land use, regrowth, production and emissions. Burning biomass releases carbon dioxide and may cause air pollution.
Glossary
- Biofuel
- A fuel made from recently living biological material.
- Biomass
- Organic material from organisms, containing chemical energy and sometimes used as fuel.
- Sustainable energy
- Energy supplied in ways that can be maintained over time while limiting environmental and social harm; it is not entirely pollution-free.
- Fossil fuel
- Coal, oil or natural gas formed from ancient organic remains over geological timescales.
- Tidal energy
- Energy obtained from tidal movements of seawater.
- Nuclear energy
- Energy released from changes in atomic nuclei, including fission in nuclear power stations.
- Hydropower
- Energy obtained from flowing or falling water.
- Wind energy
- Energy obtained from the movement of air.
- Solar energy
- Energy obtained from solar radiation.