2.12 Biofuels

Question 1

What can Biofuels be made from?

Answer 1

Many different things, from farm waste, animal droppings and landfill rubbish to specifically grown crops (e.g. sugar cane, vegetable oils or trees)

Question 2

Fossil fuels and biofuels are both made from living organisms. Why are they different?

Answer 2

Fossil fuels are made from organisms that lived millions of years ago and were converted to fuel from a very different process. Biofuels are made from recently living organisms

Question 3

Why are plants or algae usually used to make biofuels?

Answer 3

They can photosynthesise and so they can lock up the suns energy which can then be released later when we burn them for fuels

Question 4

Why are biofuels considered ‘carbon renewable’?

Answer 4

Burning them releases CO2, but the plants you grow remove CO2 from the atmosphere. There’s debate about whether there’s no net change, as this only works if you keep growing plants at the rate that you’re burning things.

Question 5

Are biofuels renewable or non-renewable and why?

Answer 5

Renewable - we can grow biofuels over and over again

Question 6

What are 4 disadvantages?

Answer 6

• Hard to respond to immediate energy demands, as crops take time to grow (you can stockpile biofuels to combat this)
• The cost to make biofuels is very high
• Some worry that growing crops specifically for biofuels could lead to there not being enough space or water to grow enough crops for food for everyone
• In some places, large areas of land have been cleared to grow biofuels, resulting in species losing their habitats. The decay and burning of this vegetation also increases CO2 and methane emissions

Question 7

What are 3 benefits of biofuels?

Answer 7

• Easy to transport
• Can mix them with fossil fuels
• Renewable resources

Question 8

Why is the fact we can mix biofuels with fossil fuels a benefit?

Answer 8

It means we can benefit from biofuels without having to get new cars. Other renewable fuels like solar and wind have to be converted to electricity and so would require entirely new vehicles, which is unlikely to happen any time soon

Question 9

In theory, biofuels should be carbon neutral, but in reality they are not. Why is this?

Answer 9

In order to grow the biofuels, we often have to clear land by cutting down trees. This means the trees can no longer photosynthesise and absorb CO2 themselves, and will also release large amounts of CO2 if burned.

In addition, it usually requires a lot of energy to harvest, process, and transport the biofuels, which itself will produce a lot of CO2