DF - sustainability

Question 1

alternative fuels

Answer 1

Renewable fuels - wind, solar, wave power, biofuels,

Hydrogen cells

Question 2

Benefits of wind, solar, and wave power

Answer 2

renewable and carbon neutral (however CO2 given out during manufacture of solar panels, wind turbines etc)

Question 3

risk of wind, solar and wave power

Answer 3

• not sufficiently reliable (not always windy or sunny)
• takes a lot of wind turbines, solar panels or wave energy collectors to even get a fraction of the energy currently supplied by fossil fuels

Question 4

Biofuels - how are they made

Answer 4

Biofuels are fuels made from living matter over a short period of time

Question 5

biofuels - how is bioethanol made

Answer 5

bioethanol is ethanol made by the fermentation of sugar from crops such as maize

Question 6

biofuels - how is biodiesel made

Answer 6

biodiesel is made by refining renewable fats and oils such as vegetable oil

Question 7

biofuels - how is biogas made

Answer 7

biogas is produced by the breakdown of organic waste matter

Question 8

Benefits of biofuels

Answer 8

• carbon-neutral, although produce CO2 when they are burnt, but CO2 is absorbed by the plants when growing
• biogas and biodiesel can be made from waste that would go to landfill

Question 9

Disadvantages of biofuels

Answer 9

• CO2 is given out while refining and transporting the fuel as well as making the fertilisers and powering agriculture machinery used to grow and harvest the crops
• switch from fossil fuels to biofuels in transport would require petrol car engines to be modified to use fuels with high ethanol concentrations
• land used to grow crops for fuel cannot be used to grow food.
  developed countries - will create a huge demand
  developing countries - could use this as a way of earning money and convert farming land, may not grow enough food to eat

Question 10

How can hydrogen be used as fuel?

Answer 10

hydrogen gas can either be burnt in a modified engine, or used in a fuel cell

• a fuel cell converts hydrogen and oxygen into water, this chemical process produces electricity.

water is the only waste product

Question 11

advantages of using hydrogen for fuel

Answer 11

• can be obtained from sea water

- water is the only waste product

Question 12

Disadvantages of using hydrogen for fuel

Answer 12

• take energy to extract hydrogen from seawater, method used determines how environmentally friendly the fuel is. If energy comes from renewable source, wind or solar, pretty much carbon neutral
• difficulties in transporting and storing hydrogen. Highly flammable and has to be liquified due to low energy to vol. ratio of hydrogen gas. which means building a whole new fuel supply infrastructure (chemical plants, network of refueling stations, pipelines)
• oxides of nitrogen can be produced if hydrogen is burnt in air at high temperatures

Question 13

to ensure energy security - uk government’s plan

Answer 13

• encouraging the public and industry to become more energy efficient
• continuing to make use of coal, oil and gas reserves
• creating financial incentives to reduce CO2 emissions
  may have to pay for each tonne of carbon they emit, so attractive for businesses to incorporate CCS
• using more renewable resources
• encouraging research of new energy sources

Question 14

ensuring energy security - brazil

Answer 14

decisions different for different countries

• brazil has few oil resources but has large amounts of agricultural land and a good climate
  so, may concentrate on growing crops in order to produce biofuels

Question 15

Carbon capture and storage (CCS)

Answer 15

Technology may be able to reduce CO2 emissions - this involves burying CO2 before it reaches the atmosphere

Question 16

Why is a strategy needed for energy security ?

Answer 16

• demands for energy are increasing rapidly as world’s population grows and as countries get richer
• climate change is also a big problem