Renewable and Non-Renewable Energy

Section 1 of 6Two kinds of energy resource

Renewable

• Renewable A renewable resource is replenished at least as fast as it is used, so it will not run out.
• Examples are hydroelectric, wind, wave, tidal, solar, geothermal and biofuels.

Non-renewable

• Non-renewable A non-renewable resource is used faster than it forms, so the supply is finite and will eventually be exhausted.
• Examples are coal, oil, natural gas and nuclear fuel.

Why use a mixture

• Why use a mixture Every technology has strengths and weaknesses,
  • so a country combines several to keep supply reliable and to limit the drawbacks of any one.

Section 2 of 6Renewable technologies compared

Technology	Advantages	Disadvantages
Hydroelectric	Reliable; large output; starts almost instantly; no pollution during use; no fuel cost	Dams flood land and displace people and wildlife; very expensive to build; drought reduces supply
Wind	No pollution or fuel cost; farmland can still be used	Unreliable because the wind varies; each turbine gives little power, so many are needed; some find them unsightly
Tidal and wave	Tidal output is predictable; no fuel cost; no pollution; can be started quickly	Few good sites; barrages flood estuaries and harm habitats and shipping; waves are not consistent
Solar	Useful in remote places; can sit on rooftops; no pollution; modest set-up cost	Works only in daylight; each cell gives little power; solar farms need a lot of land
Biofuels	Crops are carbon neutral over their life because growth absorbs the carbon dioxide released when burned	Needs a lot of farmland; carbon dioxide is still released when burned
Geothermal	Reliable; small stations; cheap to run	Few suitable locations; harmful gases can escape from underground

Section 3 of 6Non-renewable resources

Finite energy sources

Fossil fuels

• Fossil fuels Coal, oil and gas release energy on demand when burned, so supply can follow demand.
• Burning them releases carbon dioxide, which adds to the greenhouse effect, and some also release sulfur dioxide that causes acid rain.

Nuclear fuel

• Nuclear fuel Uranium and plutonium release a very large amount of energy from a small mass and produce no carbon dioxide while running.
• The waste stays radioactive for a very long time and must be stored safely, and an accident would be serious.

Supply

• Supply Once the reserves are used up they cannot be replaced within a human lifetime, so reliance on them is not sustainable.

Section 4 of 6Judging a resource

1

Decide whether the supply is reliable or depends on weather or time of day.

2

Consider how quickly the station can respond to a change in demand.

3

Compare the building, running and fuel costs.

4

Assess the environmental impact: emissions, habitat loss, waste and visual impact.

5

Give a balanced conclusion that weighs the points for and against.

Section 5 of 6Key terms

Term	Meaning
Energy resource	A store of energy that can be used to generate electricity, heat buildings or fuel transport.
Renewable	Replaced at least as fast as it is used, so it does not run out.
Non-renewable	Finite; used faster than it can be replaced.
Fossil fuel	A fuel formed over millions of years from the remains of living things, such as coal, oil or gas.
Carbon neutral	Releasing no more carbon dioxide overall than was absorbed while the fuel was growing.

Section 6 of 6Exam technique

1

Calling nuclear power renewable; the fuel is finite even though no carbon dioxide is released during operation.

2

Saying renewable sources cause no environmental harm; dams, barrages and wind farms all have impacts.

3

Describing biofuels as emitting no carbon dioxide; they release it but it was absorbed during growth.

4

Giving only advantages or only disadvantages when a question asks for an evaluation.