Topic 1 - Energy Generation

Question 1

1 kwh = ? J/s

Answer 1

1000 J/s

Question 2

name 3 types of hydropower

Answer 2

Run of River, Pump & Store, Large scale store

Question 3

Why is SOx reduction seen but less so in NOx?

Answer 3

SOx is related to energy production whilst NOx is related to transport

Question 4

Challenges of Wind Power

Answer 4

Very variable supply
ideal location on high carbon peatlands
dissolved carbon in waterways mobilises other metals

Question 5

Impacts on carbon from Wind Power

Answer 5

Peatland locations are ideal
Construction dries Peatlands
Increase oxygen and thus aerobic decomp
wet & cold slows decomp rate

Question 6

Strategies to mitigate impacts of Wind Power

Answer 6

Use floating rods for foundations
Reuse the peat if stored well
special licence needed to store peat
issues with reliability of storage centres

Question 7

Discuss Three Gorges Power Plant

Answer 7

Equivalent to 15 nuclear pp
World largest Hydro power plant
submerged much of the surrounding vegetation
displaced population
methane and CO2 production from submerged vegetation

Question 8

Negative impacts of Hydro Power

Answer 8

Reservoirs are big contributors to mehtane emission (6-7%)
Emit 20% of global CO2

Question 9

Benefits of Geothermal Energy

Answer 9

operates 24/7
constant fuel supply
consistent base load

Question 10

Shallow Geothermal

Answer 10

~500m depth
Low grade heart
from solar radiation
distributed via meteoric water, GW and water from old coal mines

Question 11

Deep Geothermal

Answer 11

> 500 m depth
primordial heat from earths formation
heat from radioactive decay
inject water to extract heat
UK - need to fracture rocks to extract

Question 12

Binary Cycle Geothermal Plant

Answer 12

water pumped in loop into and out of ground
heat transferred to external water loop that generates steam and powers a turbine
closed loop => no pollutant release

Question 13

How do Geothermal Plant work?

Answer 13

Flash Steam
- rapid depressurisation
- used to power turbine
Dry steam
- steam drawn directly through turbine
- condenser turns back into water
- no mineral laden brines

Question 14

Name 4 types of energy storage

Answer 14

Physical - pumped hydro
Chemical - battery
Mechanical
Hydrogen - still hypothetical

Question 15

Advantages of Li-Ion batteries (list 7)

Answer 15

Charge and discharge quickly
stable voltage
high E density
low maintenance
80% usable capacity
Long life
cheaper per kWh

Question 16

Disadvantages of Li-Ion batteries (list 6)

Answer 16

More expensive upfront
Lithium brine deposits
relies on other elements for anode and cathode
phosphate needed but also needed for food
Phosphate in geopolitically unstable regions
titanium needed
Performance decreases as temp increases and as used more

Question 17

Environmental Concerns of Lithium Brine

Answer 17

Extraction of lithium brine needed lots of land
large water use
CO2 emissions
depletes geothermal waters
fish deaths

Question 18

End of Life process for Lithium Ion Batteries

Answer 18

5% recycling rate
pyrometallurgy - melt in furnace
hydro metallurgy - use acidic/basic solution
direct metallurgy - reuse and seperate
bio metallurgy - custom organisms

Question 19

Minimising fires in disposal of Li-Ion batteries

Answer 19

discharge before disposal
remove flammable electrolyte
store in clay

Question 20

Advantages of Vanadium Batteries

Answer 20

Non-flammable electrode
Longlasting
Scalable - no addition metal required just more liquid

Question 21

Disadvantages of Vanadium Batteries (fuel, health etc.)

Answer 21

cost more per kWh (newer tech)
extracted from ground
not recycled
mined in Amazon
toxic and hazardous metal
interferes with haemoglobin
interferes with sodium and neuron
cross placenta
lung cancer

Question 22

Advantages of Nuclear

Answer 22

Low land use
stable baseload
low life time emissions
high energy to fuel ratio

Question 23

Disadvantages of Nuclear

Answer 23

nucealr waste
water use
high cost
highly regulated

Question 24

Process of nuclear power production

Answer 24

Uranium powered
step 1 - open cast mining
step 2 - refine ores
step 3 - use centrifuge to seperate isotopes

Question 25

Detailed steps? from diagram

Answer 25

see screenshot on desktop

Question 26

What happens to spent fuel

Answer 26

Thermo oxide reprocessing plant
uses aqueous and organic solvent to seperate U and Po
fuel rods stored under water 6-12 months

ILLW - neutralised on site, stored in steel canisters

HLLW - vitrified (turned to glass), stored on site in steel containers

HLSW - stored on site in steel containers

Question 27

Challenges of on site waste storage

Answer 27

high level of land use
degradation of steel canisters
waste used as weapons

Question 28

Alternative storage strategies for nuclear waste

Answer 28

deep disposal
- multi level barriers physical, chemical and geological
- stable geology needed
Waste isolation plant (pilot)

Question 29

Impact of Chenobyl on the environment + how to minimise effects

Answer 29

deposited caesium throughout Europe
Caesium in human consumables

removed caesium by immobilising on clay exchange with potassium

Question 30

Advantages of salt thorium reactor

Answer 30

Less Po produce
less nuclear waste
Thorium fuel cycle is self sustaining
Thorium mining is safer, more efficient and higher yielding

Question 31

Disadvantages of salt thorium reactor

Answer 31

reaction is slow
extensive reprocessing
complicated and expensive testing
special licensing needed
higher cost of fuel and refabrication
thorium can decay to uranium that emits gamma rays and another isotope that can be used for weapons

Question 32

potential of nuclear fission

Answer 32

30 years off
requires rare earth metals

Question 33

Challenges with Geothermal

Answer 33

fracture rocks = seismic activity

Question 34

1 kWh = ?? MJ

Answer 34

3.6 MJ