Week 1 - Context

Question 1

Name some sustainable energy sources and the definition of this source.

Answer 1

Sustainable energy is energy derived from sources which do not diminish as a result of extraction.

• Bioenergy
• Hydropower
• Wind
• Wave
• Solar
• Tidal
• Geothermal

Question 2

Why is renewable energy so important?

Answer 2

• Increasing energy demand
• Depletion of resources
• Energy security
• Environment impacts
• Climate changes

Question 3

Explain the different ways resource is defined.

Answer 3

• Theoretical resource is the energy embodied in the source, e.g. total energy of wind over the UK.
• Technical resource accounts for technical constraints, e.g. difficulty of construction and pre-existing infrastructure.
• Practical resource accounts for societal acceptance, e.g. exploitation in national parks/sensitive sites or ‘proximity’ to settlements.
• Economic resource varies with time, depending upon costs of inputs, regulatory regime and costs of alternative technologies.

Question 4

What is ‘Capacity Factor’?

Answer 4

Capacity factor describes generation relative to a theoretical maximum over a period.

Capacity factor = actual energy production / energy production at full capacity.

Question 5

What does ‘efficiency’ mean?

Answer 5

Efficiency describe the proportion of energy generated relative to that theoretically available:
Efficiency = Output / Input = Energy generated / Energy available

Question 6

What is reliability?

Answer 6

Reliability measures how well a system is able to fulfill its function. It is a highly complex area buy ‘availability’ is a common metric.

Question 7

What is availability?

Answer 7

Availability describes the proportion of time a generator is capable of generating over a period.
Availability = Time generator capable of generating / Total time over period

Question 8

What is carbon emissions?

Answer 8

Carbon emissions are a measure of the greenhouse gas emissions during manufacturing and operation of generators.

Question 9

What is ‘Carbon footprint’?

Answer 9

Carbon footprint attributes these to each unit of electricity generated (gCO2/kWh).

Question 10

What does ‘Avoided Carbon’ mean?

Answer 10

Avoided Carbon describes the capability for a non-fossil generator to reduce greenhouse gas emissions, largely by avoiding fossil fuel use.

Question 11

What does ‘Marginal emission’ mean?

Answer 11

Marginal emissions indicate the rate of which renewable generators avoid greenhouse gas emissions (gCO2/kWh) which depends on what fossil generation is being displaced.

Question 12

What is ‘Capital cost’?

Answer 12

Capital cost is the upfront cost of constructing an installation.

Question 13

What is ‘Operating costs’?

Answer 13

Operating costs are recurrent costs every year.

Question 14

What is ‘Levelised costs’?

Answer 14

Levelised costs area way of attributing costs to units of electricity generated.

Question 15

What is ‘Primary Energy’?

Answer 15

Primary energy is the energy found in nature that has not been subjected to man-made conversion processes.

Question 16

What is ‘peak oil’?

Answer 16

A time when production cannot increase and must decline.

Question 17

How can renewables affect energy security?

Answer 17

• Renewables offer diversification of supplies to counter domestic and or international disruption.
• Potentially domestic control of manufacturing.
• Different risk profile financially.
• Cannot be depleted.
• Reduce the need for importation of fossil fuels. This can reduce physical disruption and political disruption.

Question 18

What is the environmental impacts of fossil fuel combustion?

Answer 18

• Release of sulfur dioxide, nitrogen oxides and other gases responsible for acid rain.
• Emissions of radioactive particles.
• Release of particulates causing breathing difficulties, etc.
• Release of carbon dioxide into the atmosphere, which has been implicated in global climate change.

Question 19

What impacts does the initial production and distribution of fossil fuels?

Answer 19

• Land subsidence due to coal mining
• Cutting piles, containing toxic materials, such as heavy metals, have been found to cause ground water pollution and visual impacts.
• Oil production and transport can cause spills resulting in large-scale marine and terrestrial impacts.
• Groundwater contamination associated with mining and potentially ‘fracking’.
• Construction of power plants and infrastructure as well as decommisioning also have impacts:
  
  • Visual impacts
  • Habitat disturbance and impact on flora and fauna.
  • Disposal of spent nuclear fuel.
  • Recovery of materials or leave in situ

Question 20

What is a Life Cycle Assessment?

Answer 20

Quantitatively and objectively accounts for all energy, materials, emissions and waste products associated with a product’s entire life-cycle.