12.1 Sustainable energy supply

Question 1

Hydro-electric power (HEP)

Answer 1

Fast flowing water, from river or released from dam, is directed through turbines.
Force of water spins turbine’s blades, generating electricity.

Question 2

HEP advantages

Answer 2

Once operating, they are cheap and efficient to run.

Emits no GHG.

Reliable - little flux in water supply.

Flexible - can adjust water flow and output.

Safe - no fuel involved

Question 3

HEP disadvantages

Answer 3

Building structures on rivers and dams may harm wild life.

Expensive to build: Bakun Dam costed 2.3 billion pounds

May overflow or experience silt build up.

Construction releases CO2: 0.9 pounds of CO2 produced per pound of cement produced.

Impede salmon migration BUT fish ladders can assist this.

Can lead to droughts: Ataturk dam cut flow of Euphrates river by 1/3.

Slope instability: Vajont Dam disaster in October 9, 1983.

Affecting surrounding areas: 10,000 people had to relocate

Question 4

Areas suitable for HEP

Answer 4

Mountainous region with high rainfall.
Small-scale HEP schemes successful in LICs on a local but not national scale.

Question 5

How many percent of Costa Rica’s energy is produced by HEP?

Answer 5

95%

Question 6

How is nuclear energy created; Nuclear Fission

Answer 6

Through splitting of atoms.
Releases heat energy through radioactive decay of fuel rods, heat turns water into steam, steam turns turbines, turbines turn generators, generators make electricity.

Uranium ore is the most used.
Plutonium and Thorium can also be used.

All of today’s nuclear plants use fission to generate electricity

Question 7

Two types of nuclear power

Answer 7

1. Nuclear Fission
2. Nuclear Fussion

Question 8

Nuclear fusion generation

Answer 8

Energy released by joining of nuclei of small atoms
E.g., Deuterium and Tritium

Question 9

Advantages of nuclear power

Answer 9

1. Reduced reliance on imported fossil fuels, important for countries concerned about energy security
2. Nuclear capability, is still useful threat to keep world peace
3. Not as vulnerable to fuel prices as oil and gas; uranium is relatively plentiful and most mines are in politically stable countries
4. Tech developments have improved reliability and efficiency
5. Zero emissions of GHG when opertating
6. Very efficient: 1 station = wind farm the size of Luxembourg

Question 10

Disadvantages of nuclear power

Answer 10

1. Power plant accidents could release radiation into air, land and sea
2. Disposal of radioactive waste is major problem as it generates heat and corrodes all containers. Sites used for disposal of nuclear waste can never be used for anything else, uranium takes millions of years to lose radioactivity
3. Rogue states and terrorists may gain access to nuclear fuel and develop nuclear weapons
4. Decommissioning and constructing costs are very high; ~$6.3 billion and takes long time
5. Possible increase in certain types of cancer near nuclear plant
6. Not available in developing nations

Question 11

Hinkley C, UK (nuclear energy)

Answer 11

In North Somerset

Contribute 3.2GW to UK’s total of 16GW
Provides 7% of UK’s power (6m homes) and 25,000 jobs

Question 12

How many % of world’s energy needs is by Nuclear power?

Answer 12

11%

Question 13

What are fast breeder reactors

Answer 13

A nuclear reactors that uses fast neutrons to generate more nuclear fuels than it consumes.
Greatly increases energy generation.

Disastrous if the plutonium got into wrong hands, as it is key for nuclear weapons

Question 14

Nuclear power formula

Answer 14

Energy released =
mass of matter lost X speed of light2

E= mc2

Question 15

Nuclear compared to coal

Answer 15

Costs about the same
Nuclear do not produce smoke or CO2, many see it as solution to environmental issues caused by energy production.

Question 16

Storing of Nuclear waste in UK

Answer 16

UK’s intermediate and high level waste is encased in concrete and stored above ground.

Most low level waste is stored in sealed concrete vaults in Drigg, Cumbria

Question 17

Fuel reprocessing

Answer 17

Fuel rods remain in reactor for several years before being removed by refuelling machine.

It is left in cooling pond for 3 months to allow the short half-life radioactive waste e.g., iodine, to decay.

The fuel rods are then transported in steel flasks to a reprocessing plant and dissolved in acid.

Reprocessing allows the most radioactive materials to be concentrated and produce some material that can be reused.

Quantities of waste are small compared to other forms of power generation, but are more dangerous.

Waste disposal depends on whether it is liquid, gas or solid.

Question 18

Disposal of nuclear waste in UK

Answer 18

UK, like many other developed countries, is currently identifying sites for geological disposal of nuclear waste.

Sites will be 200m below ground and in geologically stable rocks

Question 19

Factors considered for disposal sites for nuclear waste

Answer 19

1. Availability of land
2. Local unemployment
3. Transport to site
4. Farming
5. Technology and design
6. Need to ensure the site is safe
7. Strength of local pressure groups

Question 20

How long does a nuclear power station last?

Answer 20

20-40 years.

Short compared to coal-fired stations which last over 50 years.

After retirement, it will need to be decommissioned, ridding of radio active material etc.

Question 21

The biggest producer of uranium

Answer 21

Kazakhstan

Question 22

The biggest consumer of uranium

Answer 22

France
Did not want to rely on oil

Question 23

Results of 1973 Yom Kippur war

Answer 23

Increased oil prices, nuclear became more popular

Question 24

How many percent of world’s energy is by nuclear?

Answer 24

10%