6.23 - Alternative fuels Flashcards
What are two reasons as to why we need to use alternative fuels?
- The depletion of natural resources
- Global warming and climate change
What are most alternative fuels known as?
Biofuels
What is a biofuel?
A fuel obtained from living matter that has died recently
What is an example of a biofuel?
Wood, as it can be burned
What is a renewable energy source?
One that can be continuously replaced
What is a non-renewable energy source?
One that is not being replenished, except over geological timescales
What does the term ‘carbon neutral’ mean?
If something is carbon neutral, its net carbon output by the time it has been combusted is zero
Why is a tree an example of a carbon-neutral fuel?
Because it converts carbon dioxide to oxygen while alive, but then releases carbon dioxide when burned
What is biodiesel?
A fuel made from vegetable oils obtained from plants
What are bioalcohols?
Fuels made from plant matter, often using enzymes or bacteria
What are the factors to consider when deciding if biofuels are a good replacement for natural gas?
- Land use
- Yield
- Manufacture and transport
- Carbon neutrality
What are the drawbacks of biofuels?
- They take a lot of land to produce
- Lower yield than natural gas, but this is increasing
- Costly to grow, process and transport
What are the benefits of biofuels?
- Closer to being carbon neutral than natural gas
- No drilling costs to obtain it
