DF - sustainability Flashcards

1
Q

alternative fuels

A

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

Hydrogen cells

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2
Q

Benefits of wind, solar, and wave power

A

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

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3
Q

risk of wind, solar and wave power

A
  • 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
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4
Q

Biofuels - how are they made

A

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

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5
Q

biofuels - how is bioethanol made

A

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

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6
Q

biofuels - how is biodiesel made

A

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

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7
Q

biofuels - how is biogas made

A

biogas is produced by the breakdown of organic waste matter

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8
Q

Benefits of biofuels

A
  • 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
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9
Q

Disadvantages of biofuels

A
  • 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
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10
Q

How can hydrogen be used as fuel?

A

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

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11
Q

advantages of using hydrogen for fuel

A
  • can be obtained from sea water

- water is the only waste product

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12
Q

Disadvantages of using hydrogen for fuel

A
  • 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
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13
Q

to ensure energy security - uk government’s plan

A
  • 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
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14
Q

ensuring energy security - brazil

A

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
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15
Q

Carbon capture and storage (CCS)

A

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

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16
Q

Why is a strategy needed for energy security ?

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