Biofuels Flashcards
What energy resources are included in biofuels?
Where photosynthesis has captured sunlight and the energy has been stored in materials like vegetable oils and carbs
They can include any energy resources produced by biological processes sufficiently recently that they can be renewable
What are biofuels produced from?
Some are deliberately produced, some are waste products of other processes and activities
Where can biofuels be harnessed from?
Wood
Combustible crops e.g. Miscanthus
Alcohol from carbohydrate crops e.g. wood, sugar canes
Biodiesel from vegetable oil
What waste products can be used as biofuel?
Methane from anaerobic digestion of waste
Combustible crop waste
Incineration of combustible domestic refuse
Landfill biogas
What are the advantages of biofuels?
The supply rate can be controlled
They can be stored-easy to supply demand
They can be used to make vehicle fuels to replace petrol and diesel
The fuels themselves are carbon neutral
The energy density of biodiesel and alcohol is nearly as high as that of fossil fuels
Why are biofuels carbon neutral?
They release the same quantity of carbon dioxide that they absorb in photosynthesis during growth
What are the disadvantages of biofuels?
The supply of biofuels from waste is limited to the amount produced from the source activity
The large area of farmland needed for biofuel crops may compete with food production or encourage woodland clearance
Energy density of straw is lower than fossil fuels
Intensive farming techniques to produce the crops can release more CO2
What locational constraints face biofuel crops?
The same that face arable crops
Need fertile soil, suitable climate and topography that makes cultivation easily
What locational constraints face biofuels that come from wastes?
They are produced only wherever the source activity is located e.g landfill sites and sewage works near urban areas
What is the range of environmental impacts as a result of using biofuels like?
It is a very wide range because of the wide range of biofuels available
What environmental impacts are as a result of biofuels that are produced as a part of an agricultural production system?
Habitat loss
Fertiliser use
Pesticide use
Impacts of fossil fuels to drive machinery
Name 2 new biofuel technologies
Hydrogen from Algae
Anaerobic digestion
How is hydrogen from algae being used as a new biofuel?
Some types of algae produce hydrogen in photosynthesis if they are deprived of sulphur
This hydrogen can be harnessed to be used as fuel
How is anaerobic digestion being used as a new biofuel technology?
It is a process being applied to different biological materials e.g. crop waste
Small scale projects using manure or sewage are becoming common in LEDCs
