8.4 - Biofuels

• What is the definition of biofuel?

  A fuel made from recently living organisms
• Why is the distinction of "recently living" important for biofuels?

  Because fossil fuels come from ancient organisms
• What are the primary sources of biofuels?

  Plants and algae
• How do plants and algae contribute to biofuels?

  They photosynthesize and store solar energy
• Can animal waste be used for biofuels?

  Yes, but on a smaller scale
• Why are biofuels generally considered carbon neutral?

  They absorb CO2 while growing
• What makes biofuels a renewable resource?

  They can be grown repeatedly
• What is a benefit of biofuels regarding transportation?

  They are easy to transport
• How can biofuels be used with existing vehicles?

  They can be mixed with fossil fuels
• What is a significant environmental concern with growing biofuels?

  It may involve converting natural land
• What is a consequence of converting natural land for biofuel production?

  It can damage the environment and release CO2
• What energy requirements are associated with biofuels?

  Harvesting, processing, and transporting require energy
• How effective are biofuels compared to initial expectations?

  They are not as good as first thought
• What are the pros and cons of biofuels?

  Pros:

  • Carbon neutral when grown
  • Renewable resource
  • Relatively cheap to produce
  • Easy to transport
  • Can be mixed with fossil fuels

  
  

  Cons:

  • Requires land conversion
  • May damage the environment
  • Energy-intensive production process
• How should biofuels be used according to the video?

  Used where it makes sense, not exclusively
• A big benefit of biofuels is that they can be used in the vehicles that we already have.

  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. 
• • Biofuels are mostly made from recently living organisms, such as plants and algae. But they can also be formed from animal waste.
  • This is in contrast to fossil fuels, which are made from organisms which died millions of years ago. 
  • In both cases though, plants and algae can trap the suns energy as part of photosynthesis, and this energy is released when we combust the fuel. 
• What are the advantages of biofuels?

  • They're renewable 
  • They're easy to transport 
  • They can be used in cars 
• What are the disadvantages of biofuels?

  • They require a lot of energy to harvest, process and transport 
  • They require a large area of land to grow
• What do we mean when we say that 'biofuels are carbon neutral'?

  They absorb the same amount of carbon dioxide while growing, as they release when they're burned
• In theory biofuels should be carbon neutral, but in reality they are not.

  Why is this? 

  • Trees may be cut down, so no longer absorb CO2
  • Trees may be cut down, and will release CO2 if burned 
  • Energy will be required to harvest, process and transport the biofuels which will release more CO2