Describe the trend for currently-producing oil fields shown on the graph for the period 2015–2030.

Suggest two possible reasons for the trend you described in (a)(i).

Reason 1:

Reason 2:

Briefly suggest what is meant by “unconventional” oil and gas.

Explain two limitations of one named source of renewable energy.

Source of renewable energy:

Limitation 1:

Limitation 2:

Award [1] for each of the following, up to [3]. Quantification required for award of full marks.

• declining
• initially at a fast rate
• then later at a lower rate
• rate of decline changes.

Award [1] for each valid distinct reason.

Possibilities include:

• exhaustion of existing fields
• it has become too expensive to extract
• political or government action to reduce fossil fuel use/dependence
• there is an increase in alternative sources of cleaner and/or cheaper energy / reduced demand for oil
• production from other oil fields will increase.

Award [1] for a valid definition of “unconventional” – it is oil/gas not obtained from conventional oil/gas wells/drilling/extraction methods.

Award further [1] for naming a source, such as oil sands; oil shales; or from coal/biomass/liquids produced from the chemical processing of gas or fracking.

Renewable sources of energy include solar, wind, geothermal, hydro-electric, biomass. Accept nuclear as renewable.

In each case, award [1] for valid limitation and [1] for further development/detail.

For example: Solar – not applicable to all areas / seasons / times of day [1], including times like winter when demand in cool climates is highest [1].

Other possibilities include:

• reliance on weather
• production capacity
• expense of start-up/storage
• environmental issues
• efficiency of production / unit costs of power produced
• affordability for less developed nations.