ELA Past Paper Questions

Question 1

Explain how the direct benefit of a green product may not present the whole picture

Answer 1

• Knock-on effect for example transportation (expressed well with sankey diagrams)
• LCA, which is sometimes used to show how green a product is, can be very subjective and tailored towards certain products and thus can be misleading about the true environmental impact of the product

Question 2

Challenges of LCA?

What are the different categories and how are they compared?

Answer 2

Quality and quantity of data.
Implementing a uniform methodology.
Defining the scope.
Complex systems.
Allocation difficulties.
System interactions/ system expansion.
Interpreting results.

Categorising emissions to simplify such as GWP AP EP POCP.

Normalisation is used to compare relative effect such as annual impact on citizen.

Question 3

What are the values of performing LCA?

Answer 3

Identify hotspots
Identify major burdens
Sensitivity analysis
Measuring impact
For comparison
Decision making
Marketing
Public policy making

LCA avoids narrow outlook on environmental concerns by:

• Compiling inventory of relevant energy and material inputs and environmental releases
• Evaluating the potential impacts of these things
• Interpreting the results to help make an informed decision

Question 4

Rank methods of distribution burdens

Answer 4

System expansion (system expansion does increase the complexity of the model)
System expansion with allocation
Allocation with physical relationships (do no vary with time, and often relate to value)
Allocation with economical basis (vary with time)
Allocation by mass rate (allocates equally)

Question 5

List allocation methods with examples

Answer 5

Calorific, bioethanol and distillers waste from wheat and soybean
Economic, meat product and manure as by-product, crude oil and separation
System expansion, bran from flour which replaces spring barley as animal feed, and newspaper recycle used in building insulation.

Question 6

What are the reasons why emissions inventory of LCA might be affected by country or region in which the assessment is carried out?

Answer 6

• Energy mix; emissions per MJ consumed depend on source
• Distances travelled by raw materials/ products and mode of transport
• Preferences in use of product
• Waste water treatment

Question 7

LCA critique

Answer 7

Rigid system boundaries - boundary critique.
Accuracy and availability of data, based on averages, outdated information.
Statistical information can be swayed to favour certain products, and major assumptions used.
However there are guidelines to help reduce such conflicts.

Question 8

What are the advantages and disadvantages of energy from waste?

Answer 8

Advantages: cheap fuel, stops it from going to landfill, fuel is always available as waste will always be produced, reduces the energy required from other processes

Disadvantages: harmful emissions - burn less cleanly than other fuels, installation and running cost of incineration facility

Question 9

What are 4 carbon capture technologies that are currently being proposed and evaluated?

Answer 9

Capture techniques: post combustion capture, pre combustion capture, oxy-fuel combustion, air sucking

Storage options: geological formations (depleted oil and gas reservoirs and deep saline aquifers, unmineable coal seams), deposition into water on deep ocean floor, conversion into solid minerals

Question 10

Why can system expansion be fairer?

Answer 10

By identifying a true emissions burden associated with a product, system expansion can determine a fairer allocation.

Question 11

The continuing use of fossil fuels is a concern of many people why is this?

Answer 11

Release of CO2 emissions are thought to be a result of climate change.
Fossil fuels are depleting resources and will need to be replaced by something else.