Past paper questions

Question 1

Discuss the link between a nations Ecological Footprint and its Carbon Footprint.

Answer 1

Answer should include mention of the following.

A carbon footprint measures the total greenhouse gas emissions caused by a person, group or nation, this being mainly as a result of the combustion of carbon based fuels to meet their energy needs.

The ecological footprint on the other hand considers the broader environmental impact of all the population of a nation by quantifying the amount of land that is required to support all the activities of that nation.

Including food production, waste disposal etc, as well as energy production.

Therefore the carbon footprint measures just one of the many environmental impacts that are included within the calculation of the ecological footprint.

Question 2

Define and explain the concept and measurement of an ecological footprint.

Answer 2

An ecological footprint is based on consumption over a specific year.

Expressed as the amount of land and sea (bio-productive area) required to support the use of natural resources.

A means of comparing usage of natural resources and lifestyles, and checking this against natures ability to provide for this

Question 3

Define “one planet living”

Answer 3

Studies show that each person is entitled to 1.84 hectares, but the table above shows that those living in developed nations use considerably more than they are entitled to, while those in the less developed countries exist on much less.

The concept of One Planet Living requires that everyone live within the 1.84 hectares that they are entitled to.

Question 4

The global ecological footprint for each person can be calculated as 1.84 hectares.
Explain.

Answer 4

People living in highly developed western countries have a much larger footprint and are effectively taking up more than their fair share of the earth’s resources.

To make the ecological footprint more ‘equal’ actions need to be taken within the developed world to reduce individual impact and support given to the developing world to develop in a more sustainable fashion.

These actions could include;
 Reduction in individual transport, or
 Less flying on aircraft, or
 Producing less waste, or
 Increasing home efficiency,

Question 5

identify and describe 3 methods required by today’s society if One planet living is to be achieved.

Answer 5

 Zero Carbon.
Making buildings more energy efficient and delivering all energy with renewable technologies.

 Zero waste.
Reducing waste, reusing where possible, and ultimately sending zero waste to landfill.

 Sustainable transport.
Encouraging low carbon modes of transport to reduce emissions, reducing the need to travel.

 Sustainable materials.
Using sustainable healthy products, with low embodied energy, sourced locally, made from renewable or waste resources.

 Local and sustainable food.
Choosing low impact, local, seasonal and organic diets and reducing food waste.

 Sustainable water.
Using water more efficiently in buildings and in the products we buy; tackling local flooding and water course pollution.

 Land use and wildlife.
Protecting and restoring biodiversity and natural habitats through appropriate land use and integration into the built environment.

 Culture and community.
Reviving identity and wisdom; supporting and participating in the arts.

 Equity and local economy.
Creating bioregional economies that support fair employment, inclusive communities and international fair trade.

 Health and happiness. Encouraging active, sociable, meaningful lives to promote good health and well-being.

Question 6

list the options available for the waste management hierarchy in order to descent.

Answer 6

1. Prevention
2. Reduce
3. Re-use
4. Recycling
5. Energy recovery
6. Disposal

Question 7

How does The Waste Management Hierarchy affect the availability of materials for incineration.

Answer 7

The waste management hierarchy indicates that prevention, re-use and recycling is more desirable than incineration as a disposal mechanism.

This may reduce the total volume of waste requiring disposal.

Question 8

Explain the key differences between a ‘bioreactor’ landfill and ‘dry tomb’ landfill.

Answer 8

Bioreactor – encourages the decomposition of the waste through the re-injection of leachate and microbe rich water.

Plus one from;
 The waste is no compacted to facilitate the flow of air and water thereby encouraging the chemical decomposition.

 As a result of the decomposition additional waste can be added.

 Gas and leachate are collected and treated.

Dry tomb – discourages reactions taking place.

Plus one from;

 Body of waste is sealed and there are high rates of compaction along with minimum flow of rainwater and leachate through the landfill.

 Waste can subsequently be stored for material value in the future.

Question 9

Discuss the advantages and disadvantages of recovering energy from waste by incineration. Your answer should make specific reference to the following issues associated with energy recovery from waste incineration;

 Environmental Issues.

 Economic issues.

 Security of supply issues.

Answer 9

Environmental Issues;

 Reduce volume of waste sent to landfill significantly (by approx. 90%).

 There is a negative public perception about the emissions and the technologies involved (NIMBY) – Not In My Back Yard.

 Residue from flue gas treatment process or from bottom ash may go to landfill as hazardous waste.

 Stack emissions (flue gases) can be treated to by ‘scrubbing’ or filtering or electrostatic precipitation.

Economic issues;

 Incineration plants can generate lots of electricity and can also provide local district heating (especially of close to urban areas).

 Energy from waste reduces the amount of landfill tax that has to be paid by business.

 Bottom ash residue may be recycled for building materials.

 Incineration plants are costly and so need high utilisation to be cost effective.

Security of Supply Issues.

 To be effective energy from waste plants need a secure supply.

 Minimum or guaranteed tonnage may be needed by operator to cover costs.

 Risks to supply due to increased exports of waste to countries with lower gate fees.

 Risk to supply due to illegal activity regarding gate fees.

Question 10

‘The diversion of biodegradable waste to anaerobic digestion can reduce greenhouse gas emissions from landfill.

For e.g. capturing the biogas from one tonne of food waste will save between 0.5 and 1.0 tonne of CO2 equivalent.

Explain how anaerobic digestion results in the production of biogas.

Answer 10

Hydrolysis – insoluble polymers broken down to soluble organic compounds.

Acidogenesis – soluble organic compounds fermented into volatile fatty acids and alcohols.

Acetogenesis – alcohols and fatty acids converted into acetic acid and hydrogen.

Methanogenesis – bacteria convert acetic acid and hydrogen into methane and carbon dioxide / biogas.

Question 11

Outline how anaerobic digestion can deliver both heat and power.

Answer 11

Biogas from an AD plant can be burnt in a combined CHP plant, this generates power (electricity) and heat.

Instead of losing the heat, as in traditional power plants, it is diverted into a local heating system. This is co-generation.

Question 12

A household decided to install insulation in the loft. State one environmental benefit gained by doing this.

Answer 12

Environmental benefits: Any one from:

 Reduced carbon emissions.

 Increased levels of home comfort.

 Reducing likelihood of condensation and mildew

Question 13

Describe two measures that could be taken to improve the energy efficiency of the outside of Amy’s bedroom.

Answer 13

Any two from;

 Adding additional insulation (Internal / External / Cavity) to the external wall will improve energy efficiency.

 Improved glazing (double / triple / Low E) will improve energy efficiency of the room.

 Improving air tightness around windows will mean the building is more energy efficient.

Question 14

Define what is meant by the U-Value of a construction material.

Answer 14

The U-value for a particular construction material is the rate at which heat is conducted away through 1m2 of the material for each 1 degree difference in temperature {1} between the outside and the inside of the building

Question 15

Explain why installing cavity wall insulation and double glazing improves the energy efficiency of a building.

Answer 15

The higher the U value, the more heat is lost from the building through the construction materials.

Refer to the comparison of U-values between specialised materials. e.g. single glazed windows vs. double or triple glazed.

Question 16

Discuss the role of technology in meeting growing global need for resources. Your answer should include specific reference to the following issues;

 What trends you deduce from the figure above with relation to environmental impact of various countries and why this might be so.

 How ecological footprints are likely to change with economic progression in developing countries.

 Population: how population size affects demand fro resources and waste generated.

 Affluence: how lifestyle / wealth affects demand for resources and waste generated.

 Technology: how counties convert natural resources into real good and services that we can use.

Answer 16

Answer;
Indicative content;

 What trends you deduce from the figure above with relation to environmental impact of various countries and why this might be so:

 More economically developed countries have a higher ecological footprint per person than less economically developed countries.

 They consume more goods and services, have more energy intensive lifestyle and create more waste.

 How ecological footprints are likely to change with economic progression in developing countries:

 As countries become more economically developed their ecological footprint is likely to increase.

 This may be due to improved education, health / life expectancy, affluence, lifestyle etc which drives demand for resources.

 Population: how population size affects demand fro resources and waste generated:

 More population means greater demand for natural resources.

 More food and water required.

 More demand for clothing, shelter, goods and energy to produce these.

 Less resources available for other species (wildlife, habitat etc)

 Affluence: how lifestyle / wealth affects demand for resources and waste generated:

 Greater affluence – greater consumption and more waste generated.

 It is unsustainable to continue living a high consumption western lifestyle.

 Developing countries wish to have a similar affluent lifestyle to the US.

 Technology: how counties convert natural resources into real good and services that we can use:

 Industrially-driven societies are energy intensive by nature.

 There are limits to how far we can improve technology in terms of resource use and reduce waste generation.

 Less advanced technology used in developing countries is likely to cause more environmental impact.

 Renewable resources still require non-renewable resources during manufacture and are expensive to harness.

Question 17

Northern Ireland remains over reliant on landfill. As old landfill facilities close, new ones are required.
Describe four difficulties associated with locating and developing new landfill sites.

Answer 17

Location;
Any two points from;

 Planning permission is required which can delay the landfill becoming operational by several years.

 A permit is required for operation which requires that full surveys have been carried out. This process is time consuming and adds to the upfront cost for the operator.

 There may be objections from local residents due to noise / odour / issues. This will delay planning permission being granted and subsequent award of a permit.

 Suitable transport links are required so that waste can be brought to the site in heavy goods vehicles.

Development;
Any two points from;

 Once a permit / licence has been granted it takes a further 18 months from the beginning of construction to operation adding to up-front investment costs.

 The site must be geographically suitable so that the polluting leachates from the site cannot affect the surrounding land and water.

 A detailed site survey is required prior to operation to ensure that the landfill site will not cause movement of the surrounding land.

 An environmental assessment is required to confirm that the effect of the landfill site on the local environmental is minimal.

 The landfill must include leachate and landfill gas treatment measures to minimise water and air pollution.

 Leak detection is required as flammable methane gas can be released. Methane gas is a greenhouse gas.

Question 18

The Northern Ireland Waste Management Strategy identifies major waste types.
Name one major waste type.

Answer 18

Any one from;

 Municipal waste

 Commercial and industrial waste.

 Construction, demolition and excavation waste.

 Hazardous waste.

 Agricultural waste

Question 19

Explain the following key terms with anaerobic digestion.

1 – Low solids;

2 – High solids;

3 – Residence time;

4 – Single-stage;

5 – Multi-stage;

Answer 19

Low Solids - Low solid digestion is where the feedstock is around 15% solid material.

High solids - High solid digestion is where the feedstock is around 55% solid material.

Residence time - The time taken for the full degradation of the material in an aerobic digestion system.

Single stage - The biological reactions occur in one holding tank and the biogas comes from this tank. `

Multistage - Hydrolysis, acetogenesis and acidogenesis occurs in one tank whilst the methanogenesis which produces the biogas occurs in a separate tank.

Question 20

Home composting is encouraged by many local councils. Name three types of waste product which can be composted in a domestic situation.

Answer 20

Any three from;
 Lawn clippings.
 Shredded stalks.
 Vegetable peelings.
 Hedge clippings.
 Cut flowers.
 Tea bags.
 Leaves.
 Eggshells.

Question 21

Explain briefly why composting is unsuitable for treating any form of catering waste.

Answer 21

Cooked food must never be used in composting because it will attract vermin.

Question 22

(a) A family is considering putting cavity insulation into the walls of their home. State one economic benefit and one environmental benefit of energy conservation to be gained by doing this.
(b) Unfortunately the family does not have the necessary finances to install wall insulation straightaway. Outline two different ways in which they might changes their day to day behaviour in order to minimise their energy consumption for home heating.

Answer 22

(a)
Economic benefits: Any one from;

 Reducing heating costs.

 Improving the value of your home.

 Grant assistance available for the work.

Environmental benefits: Any one from;

 Reduced carbon emissions.

 Increased levels of home comfort.

 Reducing likelihood of condensation and mildew.

(b)
An outline which covers at least two of the following;

 Turning down their heating controls / thermostat could reduce boiler running time.

 Closing windows and doors when heating is on could reduce heat loss through openings.

 Turning heating off at night and when house is unoccupied could reduce boiler running time.

 Putting draught excluders on doors to reduce heat loss through draughts.

Question 23

Describe one energy efficiency measure which could be implemented on a window and explain why this measure would improve the energy efficiency of the window.

Answer 23

Any one measure and explanation from;

 Sealing around the edges of the window. This will improve the airtightness and reduce the heat loss caused by draughts.

 Install double (or triple) glazing windows. These will have improved U-values and will reduce heat loss through window.

Question 24

state all three sections of the Zero Carbon Homes Hierarchy

Answer 24

1. Allowable Solutions
2. On site low/zero carbon heat and power.
3. Fabric energy efficency

Question 25

Explain two core requirements for a Zero Carbon Home.

Answer 25

 The fabric performance must, at a minimum, comply with the Fabric Energy Efficiency Standard (FEES).

 Any CO2 emissions that remain after consideration of heating, cooling, fixed lighting and ventilation, must be less than or equal to the Carbon Compliance limit established for zero carbon homes.

 Any remaining CO2 emissions, from regulated energy sources (after requirements 1 and 2 are met), must be reduced to zero.

Question 26

The production of energy from wave and tides is a priority concern of Northern Ireland and a significant amount of investment is being made within both of these areas.
Evaluate the constraints in the development of wave and tidal power in the UK and Ireland.

Answer 26

Constraints:

 Significant amount of research and development to make systems which are consistently commercially viable.

 The UK / Ireland operate busy shipping lanes and therefore locating the devices is difficult – need to ensure that they do not impact on navigation.

 Devices need to be robust and able to survive significant changes in sea conditions: they are also required to withstand sea water corrosion.

 Tidal systems require a sufficient difference in high and low tides to ensure efficiency of the technology – not all locations are suitable.

Question 27

Wave and tidal energy have been described as a priority concern for Northern Ireland. Identify two main constraints on developing wave and tidal technologies in Northern Ireland.

Answer 27

 Limited availability of suitable sites.
 Environmental support.
 Government support.
 Cost of development.

Question 28

Tidal stream generators and tidal barrages are the two main generating methods for tidal power. Compare and contrast these two methods.

Answer 28

Tidal stream generators make use of the kinetic energy of moving water to power turbines.

Tidal barrages make use of the potential energy in the difference in water height between high and low tides.

With the receding tide, this potential energy is then converted into kinetic energy as the water is released through large turbines that create electrical power through the use of generators.

Tidal stream generators have the advantage of being much cheaper to build.

And do not have as much of an environmental impact as tidal barrage.

Question 29

what advantages does a tidal stream generator have over a tidal barrage installation.

Answer 29

Any two advantages from;

 They are cheaper to construct.

 They are smaller and have less environmental impact.

 The turbine blades turn slowly and have less effect on sea life.

Question 30

Outline the operational processes of an attenuator type device.

- Wave energy attenuator.
Parts: 
- Floating tubes
- Joints
- Powercable

Answer 30

Attenuator;

These devices are orientated parallel to the direction of the wave.

Attenuators are typically a series of long cylindrical floating devices connected to each other with hinges and anchored to the seabed (Pelamis).

The cylindrical parts drive hydraulic rams in the connecting sections and those in turn drive an electrical generator.

The devices send the electricity through cables to the sea floor where it then travels through a cable to shore.

Question 31

Explain how a tidal barrage generate energy form the tides.

Answer 31

 A barrage is built across an estuary with gates and turbines built into the wall of the dam.

 As the tide flow in the gates are open and the turbines are operated producing electricity.

 At high tide the gates are closed trapping the water inside.

 When water outside has fallen sufficiently (e.g. 5m) the gates are opened.

 The released water turns the turbines again producing electricity.

Question 32

Describe three environmental implications that must be considered when deciding to install wave energy convertors at a particular site.

Answer 32

Any three from;

 Impact on marine life and habitat.

 Risk of toxic pollution.

 Visual and noise impact.

 Conflict with other sea users.

Question 33

Explain how smart glass can be used to support environmental management.

Answer 33

Smart glass changes light transmitting properties when voltage is applied.

Allows individual to control the light and heat of any room, can save costs relating to heating, air conditioning and lighting.

Question 34

Discuss the benefits of a smart waste system.

Answer 34

Answer should contain some reference to the following benefits of a smart waste system:

 Identifies peak times of waste,

 Can organise disposal when required.

 Anticipate need.

 More cost effective.

 Better planning of collection of schedules.

Question 35

Explain what is meant by Carbon Capture and Storage (CCS) from fossil fuel plants.

Answer 35

Carbon Capture and Storage (CCS) is the name given to the technology and process designed to prevent carbon dioxide exhaust when burning fossil fuels from entering the atmosphere

The exhaust gas from the combustion of fossil fuels is ‘captured’ and then stored rather than being released into the atmosphere.

Question 36

Clearly outline the three main phases of Carbon Capture and Storage and the processes associated with each.

Answer 36

Phase 1 – Trapping and separating. Entails taking the gas emitted from the process and separating CO2 from the other gases which are present.

Phase 2 – Transport. Involves moving the isolated CO2 to a location for its storage normally through a system of pipes.

Phase 3 – Storage. Refers to the long term location for the captured gas. Currently this is done either underground or underwater.

Question 37

Discuss one advantage and one risk associated with geo-engineering as the deliberate modification of the Earth’s atmosphere to offset the effects of climate change.

Answer 37

Any one advantage from;

 Counteract increasing global temperatures.

 Facilitates the control of greenhouse gases

 Counteracts climate change.

 Some technologies (e.g. cool roof technologies) are inexpensive and effective.

Any one risk from;

 Risks associated with control and predictability of technologies and processes.

 Little known about the long term side effects.

 Ethical concerns and risks associated with the use of geo-engineering.

 Governance risks.

Question 38

Give one example of a ‘geo-engineering’ technique and explain how it could be applied.

Answer 38

Any one example and associated explanation from;

 Cloud seeding: where clouds are injected with crystals to produce ‘rain on demand’.

 Space reflectors: which block a proportion of the sun’s rays from entering the earth’s atmosphere thereby reducing global warming.

 Afforestation:
Whereby global scale planting of trees absorbs CO2 from the atmosphere {1}.

 Biochar: The process of ‘charring’ biomass so that the carbon it contains is locked up in the soil .

Question 39

Describe the operation of Bio-Photovoltaic (BPV) devices.

Answer 39

Bio-Photovoltaic (BPV) devices generate electricity from light energy by exploiting the photosynthesis of living organisms such as moss, algae, cyanobacteria and vascular plants

Question 40

Define what is meant by bioremediation and state two pollutants that can be treated using this technology.

Answer 40

Bioremediation – the use of microorganisms in the treatment of environmental pollution / waste.

Any two pollutants from;
 Oil spills
 Chlorinated pesticides
 Heavy metals.
 Diesel oil
 PCBs

Question 41

Describe the process of bioremediation.

Answer 41

1. Adding micro-organisms to soils.

2. To remove contaminants

Question 42

Bioremediation is defined as ‘a method of using micro-organisms to treat contaminated land’.
On a brownfield site which is to be remediated, each of the micro-organisms named in the table below have been used.
Complete the table to identify the possible pollutants that they can be used to treat.

Micro-organism:

1. Pseudomonas putida
2. Pseudomonas aeruginosa
3. Dehalococcoides ethenogenes

Answer 42

Pollutant treated:

1. used to treat organic solvents.
2. Used to treat oil contamination.
3. Used to treat halogenated hydrocarbons.

Question 43

Discuss the economic and environmental benefits of using bioremediation technology compared to traditional treatment methods.

Answer 43

Indicative content;

 Bioremediation can be carried out under atmospheric conditions.

 Bioremediation can be carried out in situ so soil is not removed from the site.

 The contaminants are reduced to (almost) zero.

 The by-products are non-toxic so water and air pollution is minimised.

 Bioremediation uses bacteria that occur naturally in the soil so the ecosystem is maintained.

 Bioremediation is economical because it does not require large energy inputs.

Traditional treatment;

 Traditional treatment is expensive because of the high energy costs (heating).

 Greenhouse gases such as carbon dioxide are produced.

 Soil may need to be treated ex situ / off site which required heavy machinery.

 Traditional treatment can produce toxic by-products which require further treatment.

 Soil may need to be disposed of after treatment which leads to increased landfill.

Question 44

There is significant research currently being undertaken into the use of genetic engineering to enhance the scope of bioremediation technology.

(I) Outline the role of genetic engineering in modifying micro-organisms for bioremediation.

(II) Identify two issues of concern from the use of genetic engineering of micro-organisms for bioremediation.

Answer 44

Micro-organisms can be genetically engineered to;

 Decontaminate a site more rapidly than unmodified micro-organisms.

 Tolerate harsher conditions.

 Remove toxic materials (such as heavy metals).

(II) Any two points from;

 Genetically engineered micro-organisms may wipe out existing bacteria.

 They may affect the existing soil ecology with unknown consequences.

 They may not behave the same way in the field as they do under laboratory conditions.

Question 45

Alpine Pennygrass is a wild flower found in many parts of Europe, the Middle East and North America. It has been shown to be very good at absorbing heavy metals such as Cadmium and Zinc from soil. It is therefore very suitable for use in phytoremediation.
Evaluate the use of Alpine Pennygrass in the decontamination of a suitable brown field site.

Answer 45

Advantages;

 The cost of phytoremediation is lower than that of traditional processes both on and off site.

 This can prove to be cost effective as the initial cost of Alpine Pennygrass is low whilst the potential for recovery of sale of contaminant metals is high.

 The plants can accumulate and tolerate high levels of toxic metal ions.

Limitations;

 Phytoremediation is limited to the surface area and depth occupied by the roots.

 The use of Alpine Pennygrass has low environmental impact although plants cannot absorb all contaminants and will eventually be killed by toxicity of the soil.

 There is a potential threat to the food chain by contaminated Alpine Pennygrass.

Question 46

Explain the process of Phytoextraction

Answer 46

Phytoextraction;
Plants ‘uptake’ metals from contaminated soils
and concentrate them in above ground plant tissue / biomass.
This is then harvested for disposal and / or metal recovery.

Question 47

Name one plant species used for Phytoextraction and the metal ore that it can extract.

Answer 47

Example: Choose one from;

 White mustard to extract copper.
 Sunflowers to extract gold.

Question 48

Define Biohydrometallurgy (Biorefining).

Answer 48

Biohydrometallurgy: The use of bacteria (micro-organisms) to extract valuable metals from low grade ore

Question 49

Discuss two advantages and two disadvantages of biorefining in relation to traditional metal extraction methods.

Answer 49

Advantages;

 Bacteria can operate successfully in low ore concentration environments such as mine tailings that would not otherwise be economical.

 Simpler and cheaper to operate than traditional metal extraction methods – less necessity for expensive machinery / processes.

 Much less environmental damage – bacteria grow naturally in mines and landscape is left untouched
.
 Bacteria can be harvested and recycled for use elsewhere.

Disadvantages;

 Bacterial ‘leaching’ process can be very slow compared to traditional smelting. This can cause cash flow problems.

 In certain circumstances the bacterial ‘leaching’ process can lead to the production of toxic chemicals. Therefore the process need to be carefully planned.

 If something goes wrong it cannot be stopped as the bioleaching process will continue with rainwater and natural bacterial action.

 If ore concentrations are reasonably high it is uneconomical and very slow compared to traditional methods.

Question 50

Fuel cells using Hydrogen are being developed as an energy source. Give two reasons why hydrogen is used in fuel cells.

Answer 50

Any two from;

 Hydrogen has a high energy density (per unit mass).

 The only by product from hydrogen is water.

 Hydrogen fuel cells are more energy efficient than internal combustion engines / electricity generators.

Question 51

Hydrogen Fuel Cells require a source of Hydrogen as a fuel.

List two methods of bulk Hydrogen production currently used.

Answer 51

Any two from;

 Steam reforming of fossil fuels.

 Electrolysis of water using high pressure and temperature.

 Photocatalytic splitting of water.

Question 52

Outline the bulk production by electrolysis of water. Your answer must include a relevant equation.

Answer 52

Answer;

Electrodes are placed in water.

An electric current is passed through the electrodes.

The water is split into hydrogen and oxygen.

2H2o + 2e = H2 + 2OH
or
2H2o = 2H2 + O2 (2)

Question 53

State one other method used for the bulk production of hydrogen.

Answer 53

Photocatalytic water splitting or steam reforming of fossil fuel gases.

Question 54

Name two of the most common forms of Hydrogen fuel cell.

Answer 54

Any two from;

 Polymer Electrolyte Membrane (PEM).

 Alkaline.

 Phosphoric acid.

 Molten carbonate.

 Solid oxide

All relevant, valid responses will be given credit.

Question 55

Question; With reference to the figure below, explain the operating principles of a PEM (Polymer Electrolyte Membrane) Hydrogen Fuel Cell. Your answer should include equations for the reactions occurring at the anode and cathode. {6}

Answer 55

Answer;

 Hydrogen is introduced which is then oxidised / chemically split into H+ ions and electrons (at the anode). {1}

 Protons migrate through the PEM. {1}

 Electrons follow a conductive path between electrodes / follow a circuit / between electrodes either side of the PEM. {1}

 Protons and electrons then re-combine at the cathode to form water and heat.

Equation:
H2 = 2H +2 e- at anode
and
4H+ + 4e- + O2 = 2H2O

Question 56

State the two gases input into a hydrogen fuel cell

Answer 56

Hydrogen and Oxygen

Question 57

With reference to the Anode and Cathode, explain the operation of a typical hydrogen fuel cell.

Answer 57

Answer;

Anode;

Hydrogen atoms (H2) are split into protons (H+) and electrons (e-) at the anode {1}.
 The protons pass through the electrolyte layer and the electrons leave the cell and follow a circuit / conductive path on their way to the cathode {1}.

Cathode:

The protons (H+) and electrons (e-) recombine at the cathode {1}. These combine with the introduced oxygen (O2) to form water (2H2O) and heat {1}

Question 58

State two possible applications of hydrogen fuel cells.

Answer 58

Answer;

Any two from;

 Stationary generation as backup or in remote locations.

 Stand-alone power supplies for telecommunications installations.

 Transport, including cars, buses, trains, boats, or portable generators.

All relevant, valid responses will be given credit.

Question 59

Discuss two challenges of using Hydrogen as an energy source.

Answer 59

Answer;

Any two from;

 Production costs – expensive to produce.

 Transport issues – lack of infrastructure.

 Safe storage – highly explosive.

All relevant responses will be given credit.

Question 60

Discuss two challenges presented by using hydrogen as an energy source.

Answer 60

Answer;

Any two points from;

 The cost of producing hydrogen gas is high due to the electricity requirement (for electrolysis).

 If the cost of hydrogen as a fuel is more than the cost of petrol or diesel the consumer will not switch to it (which will discourage investment in the technology).

 Methane can be used to produce hydrogen. There are concerns over using a fossil fuel as the raw material as it is non-renewable.

 Hydrogen gas must be liquefied in order to make storage feasible. This adds to the production costs as compression equipment must be used and low storage temperatures must be maintained.

 The low storage temperatures required for hydrogen mean that specialist delivery vessels and pipelines that can withstand these temperatures are required.

 Hydrogen is explosive so great care must be taken to ensure that it is stored safely. It must be stored in thick-walled leak proof tanks which add to the production costs.

Question 61

Comment on the trend for travelling to work and explain why there is a need for a move towards more sustainable forms of transport.

Answer 61

Answer;

Majority of population use private transport (car / van / taxi) {1}.

This uses more fossil fuels and creates more carbon emissions {1}.

Question 62

Outline three of the key challenges that must be met by those developing sustainable ways to transport people and goods in the future {3}.

Answer 62

Answer;

Response to include any three from;

 Economic viability;

 Environmental impacts

 Dependence on fossil fuels.

 User safety.

Question 63

New vehicle technologies are being developed which aim to reduce global dependency on oil as a fuel.
Name two new vehicle technologies.

Answer 63

Any two from;

 Hydrogen fuelled vehicles.

 Biofuelled vehicles.

 Electric vehicles.

 Hybrid vehicles.

Question 64

Identify one new vehicle technology that has the potential to reduce global dependency on oil as a transportation fuel and describe the infrastructure changes that would be required to allow it to work effectively.

Answer 64

Answer;

Any one from, {1};

 Hydrogen fuelled vehicles.

 Bio-fuelled vehicles.

 Electric vehicles.

Any one from;

 Electric vehicles {1} – need an extensive infrastructure planned and developed what will allow drivers to plug in their vehicles {1}. Purely electric vehicles are totally reliant on their battery pack so they will be confined to short commutes if the network of charging stations isn’t developed. Plug in cities initiative {1}.

 Hydrogen fuelled vehicles {1} – Hydrogen fuelled vehicles will require extensive hydrogen pipeline transporting hydrogen to specially equipped hydrogen filling stations {1}. Due to the physical qualities of hydrogen, health and safety is an issue which must be addressed {1}.

 Bio fuelled vehicles {1} – Greater production of biofuels required which has implications for land use {1}. Adaption required at filling stations to ensure accessibility for motorists {1}.
All relevant, valid responses will be given credit.

Question 65

Describe the processes of Biomass pretreatment and Cellulose Hydrolysis

Answer 65

Answer;

A: Biomass Pre-treatment: During this phase the biomass is treated with enzymes {1} so that cellulose material will be amenable to hydrolysis {1}.

B: Cellulose Hydrolysis: Any remaining cellulose is hydrolysed into glucose {1}. Cellulase enzymes are used to break the chains of sugars that make up the cellulose, releasing glucose {1}.

All relevant, valid responses will be given credit.

Question 66

With the aid of a chemical equation, outline what is meant by Glucose fermentation.

Answer 66

Answer;

The chemical breakdown of glucose to form ethanol.
C6H12O6 = 2C2H5OH + 2CO2

As sugars are broken down, ethanol and carbon dioxide are produced.

Question 67

The word equation below illustrates the production of biodiesel from vegetable oil using methanol and sodium hydroxide.

Soybean + Methanol +sodium hydroxide = Bio-diesel + Glycerine.

What is the name given to the type of chemical reaction that occurs between the vegetable oil and the methanol?

What is the function of the Sodium Hydroxide in the process?

Name one other type of vegetable oil that might be suitable for conversion into biodiesel.

Answer 67

(I) – Transesterification.

(II) – Catalyst.

(III) – Any one from;

 Palm oil.
 Used vegetable oil.
 Corn oil.

Question 68

Explain two advantages of using biodiesel as a substitute fuel for private and commercial vehicles.

Answer 68

Answer;

Any two from;

 Doesn’t require any radical changes to switch to the use of biofuels {1} unlike the difficulties in switching to other renewable energy sources such as solar and wind power {1}

 Are cheaper than fossil fuels {1}. Many governments are now offering tax incentives to buy greener cars that run on biofuels (ethanol being one example) {1}.

 Are considered ‘carbon neutral’ by some people. This is because the carbon dioxide they release when burnt is equal to the amount that the plants absorbed out of the atmosphere {1}. Therefore, they don’t contribute to global warming. However, it does require some fuel to power the machinery on the farms where biofuels are produced. Research suggests that they reduce carbon emissions by 50-60% {1}.

 Reduce dependence on foreign oils {1}. Oil fluctuates in price rapidly, so changing to biofuels will help buffer against the change {1}.

 Emit less particulate pollution than other fuels {1}, especially diesel {1}.

All relevant, valid responses will be given credit.

Question 69

Explain two reasons why the rising global production of biofuels is a contentious issue.

Answer 69

Answer;

Reference should be made to two of the following Biofuel issues;

 Biofuels take a large expanse of area to grow. Land will have to be cleared for more growth. Rainforests and other high biomass lands are cleared on a mass scale for biofuel production (which may happen tin lower income countries) then the amount of green-house gases emitted would be hugely significant. Multiple studies have been found to draw the same conclusion.

 Farmers in developing counties may move land away from food crop production biofuels ‘cash crop’ reducing food supplies and increasing the prices of staple foods.

 Biofuels may raise the price of certain foods which are also used for biofuels such as corn.

 As other plants are replaced, soil erosion will grow.

 A lot of water is used to water the plants, especially in dry climates.

 Deforestation in South America and South Eastern Asia causes loss of habitat for animals and for indigenous people living there.

All relevant, valid responses will be given credit.

Question 70

Policy makers employ different strategies to reduce transport demand in urban centres. One such strategy is congestion charging which was introduced in London in 2003. Assess three effects of congestion charging in central London.

Answer 70

 The use of cars went down by more than a third following the introduction of congestion charging which is evidence that it was effective.

 The use of public transport such as taxis and buses increased following congestion charging which reflects movement away from private to public transport.

 The number of buses increased by more than 50%.

 The number of bicycles in use has more than doubled.

 The overall number of vehicles entering London has gone down since congestion charging was introduced which reflects the success of congestion charging in relieving congestion.

Question 71

(Continuation to question 70)
Outline three other strategies that policy makers employ to reduce transport demand. Comment on the effectiveness of each strategy.

Answer 71

Answer;

Any three named strategies and three relevant comments on the effectiveness of each strategy such as;

 Subsidised public transport {1} makes it economically beneficial to use which increases the use of public transport {1}.

 Extending the public transport network {1} decreases journey times, increases capacity and increases the ease of access to the network which increases use {1}.

 Dedicated bus and cycle lanes {1} decreases journey times and thereby increasing the attractiveness of using these mode of transport compared with driving {1}

 Fuel and vehicle taxation {1} increase the cost of driving. This increases the use of public transport, cycling and car which reduces the number of vehicles on the road {1}.

Question 72

The following statements represent some of the issues that need to be taken into consideration when planning for towns and cities in the future;

‘’Towns and cities will have to be more energy efficient and resilient’’

‘’Measures will have to be taken to reduce the energy required to heat and cool our buildings’’

‘’Fundamentally we need to reduce the length and frequency of vehicle journeys and there is a need for more integrated transport’’

‘’Rainwater needs to be captured and utilised’’

‘’Increasing tree cover by 10% can reduce surface temperature of a city by between three and four degrees Celsius’’

‘’Urban green areas can be a significant source of sustainable food’’

With reference to the statements above, discuss the types of high and low technology solutions that you might expect to see in cities of the future.

Answer 72

Answer;
Indicative content;

 More energy efficient – Smart Grid, reduction in usage – change behaviours, less waste from recycling, application of independent energy solutions, e.g. micro heat / power generation.

 Reducing energy needed to heat buildings – zero carbon homes, building performance.

 Transportation – encourage alternative methods of transportation, e.g. cycling, walking, car share, integrated public transport timetables, greater use of bus lanes, financial incentives, use of video conferencing.

 Water collection – use of water butts, reduction in domestic and commercial water usage by financial penalties / incentives, metering, behavioural change.

 Increasing tree cover – plant more trees, designated green spaces.

 Urban green areas – greater designation of green areas, allotments.
All relevant, valid responses will be given credit.

Question 73

You have been employed as a sustainability adviser by the developer. Suggest characteristics that you would propose for an urban development that would link sustainability, zero carbon concepts and the role of technology. Your answer should include reference to the following issues;

 Reduced energy use for heating / cooling and microgeneration (including the use of smart grid technology).

 Integrated and flexible transport facilities / versatile buildings.

 Waste management / land use (brownfield sites).

 Dealing with water shortages / sustainable urban drainage.

 Green spaces – environmental benefits.

Answer 73

Answer;
Indicative Content;

 Energy use of heating / cooling and microgeneration (including the use of smart grid technology);

 Reduced energy use for heating and cooling; passive ventilation; natural cooling; better insulation, glazing, orientation.

 Microgeneration of electricity (using solar power and micro wind linked via smart grid) and heat pumps, biomass etc.

 Integrated and flexible transport facilities / versatile buildings;

 Public transport, cycling, walking, park and ride etc.

 Lower cost and more comfortable and versatile buildings / design for reuse etc.

 Integrated and flexible transport facilities / versatile buildings;

 Public transport, cycling, walking, park and ride etc.

 Lower cost and more comfortable and versatile buildings / design for reuse etc.

 Dealing with water shortages / sustainable urban drainage.

 Systems to deal with water shortage (e.g. managing water shortage, water metering, low water usage sanitaryware, rainwater harvesting, greywater recycling, etc)

 Sustainable urban drainage schemes (e.g. flood mitigation measures, SUDs).

 Green spaces – environmental benefits;

 Using green spaces to moderate the urban heat island (e.g. using trees to create shade / local microclimate / heat sinks).

 Using green spaces that work for people and wildlife, for examples food production in urban areas.

Question 74

Question: The following extracts are taken from the NI Government’s Rural White Paper Action Plan regarding their aims for promoting sustainability in rural communities:

‘’A key priority…..is to promote access to key services for all rural dwellers…. Including the provision of public transport’’

‘’We will continue to support innovative ways of improving broadband quality in rural areas’’

‘’We will….provide financial assistance for householders in areas where no water main is near their homes…have access to some other wholesale water supply’’

‘’We will continue to work…to enhance the role of renewable electricity generation and support a sustainable green economy’’

‘’We will engage with ….farm families and the agri-food sector to find opportunities to increase the procurement of fresh, local sustainable food’’

With reference to the above statements discuss the various issues that underpin the development of sustainable rural communities.

The quality of written communication is assessed in this question.

Answer 74

Answer;
Indicative content;

 The economic cost and environmental impacts of linking isolated dwellings to water, waste, energy supply, communication and transport networks.

 Application of independent energy solutions using indigenous energy sources, for example biomass, agriculture waste treatment, wind power and small scale district heating solutions.

 Potential for use of local water sources (e.g. local wells / boreholes for non-potable water: reduced need for mains drainage infrastructure).

 Use of small scale waste water treatment solutions (provision and operation of septic tanks): reduced need for mains drainage infrastructure and waste water treatment: reduced occurrence of flooding.

 Benefits of local food production and consumption form environmental, economic and social perspectives (e.g. farmers markets, community gardens / allotments: more income for farmers and local communities; more local employment; reduced transportation and ‘food miles’)

 Impact of communication technologies to enhance accessibility to rural areas without generating new travel demands (e.g. availability of high speed broadband; video conferencing; working from home).

All relevant, valid responses will be given credit.