Biofuels

Question 1

Biofuels

Answer 1

Energy resources produced by photosynthesis and/or biological processes, some biofuels are deliberately produced, others are waste products of other processes.

Question 2

Features of Biofuels

Answer 2

Predictable, low level of technology and expertise, easy to store and transport, carbon neutral

Question 3

Biofuels crops

Answer 3

wood, Miscanthus (elephant grass), coppiced willow, alcohol from carbohydrate crops e.g. sugar cane, biodiesel from vegetable, nut and seed oils

Question 4

Waste products as biofuels

Answer 4

combustible crop waste, incineration of domestic waste, landfill biogas/methane, methane from the anaerobic digestion of or organic waste such as sewage, crop and food waste

Question 5

Advantages of Biofuels

Answer 5

predictable, controlled supply, easy to store, easy to transport, applicable to electricity generation and vehicle fuels, carbon neutral, high energy density of some biofuels e.g. alcohols and biodiesel

Question 6

Carbon Neutral

Answer 6

the amount of carbon dioxide (CO2) emitted into the atmosphere is balanced by the amount absorbed or removed from the atmosphere. In Biofuels CO2 is taken in through photosynthesis and emitted upon combustion

Question 7

Biodiesel

Answer 7

Biodiesel is a renewable, biodegradable fuel that can be used in place of petroleum diesel in diesel engines, it is produced from vegetable oils, animal fats or recycled restaurant oil

Question 8

Disadvantages of biofuels

Answer 8

Supply limited to amount produced, land required for biofuels production competes reduces land for food production, Loss of wild habitats and biodiversity, energy density of some biofuels is low (e.g. Miscanthus), production releases agrichemicals, pesticides and fertilisers, into the environment, production and transport may use fossils fuels.

Question 9

New biofuel technologies

Answer 9

Hydrogen from algae, Small scale anaerobic digestion of waste (usually farm waste)

Question 10

Hydrogen from Algae

Answer 10

photosynthesising algae are deprived of sulphur and form hydrogen, hydrogen can be collected and used in fuel cells or for combustion. This has been trialed with algae in tanks on the outside of buildings.