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January Revision > Power > Flashcards

Power Flashcards

1
Q

Hydrogen Technology Negatives

A 
Uncompetitive costs (vs normal cars) (platinum)
Low membrane durability 
Hydration of fuel cell necessary (difficult at varying temperatures)
Infrastructure - pipeline, transport, fuelling station, hydrogen storage
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2
Q

India Transport Market

A

Predominantly two-wheeled vehicles - two-stroke engines with high emissions

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3
Q

Aircraft Engines

A

Turbojet, turbofan, turboprop

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4
Q

Decarbonising Air Travel

A

Planes emit NOx, Ozone and CO2
High-speed rail is an alternative
Scheduling improvements reduce air traffic delays
Video conferencing works

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5
Q

Conventional Power Station Layout

A

Boiler > high pressure turbine (with reheat) > low pressure turbine > generator > condensor > pumps > boiler

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6
Q

Hydroelectric Issues

A

Large areas of land flooded for reservoir
Non-accessible for tourists
Effect on migratory routes for fish

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7
Q

Three Gorges Facts

A

10 years to construct
Operational in 2011
Contains 26 tubine units (700MW each). Total installed capacity of 20.3GW, annual generation of 84.7TWH.
642km2 land inundated 1.13 million people displaced

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8
Q

Scottish and Southern Energy PLC

A

54 hydropower stations

Over 1000MW capcity

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9
Q

Severn Barrage

A

9m diameter bulb turbines producing 4.3% UK’s electricity
£17 billion to build
11m tidal range Bristol channel
6p/kWh is 3.3p more than typical selling price of 2.7p/kWh
Concerns - sediment build up, navigation issues, flooding control, habitat destruction

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10
Q

Gas turbine power plants

A

Heavy frame engines low compression ratio (<15)
Smaller aeroengine derivatives high compression ratios (>30)
Efficiencies above 55%
Fast to construct, low operating costs
Baglan Bay 525MW CCGT plant 60% efficiency

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11
Q

Geothermal

A

High capital costs
Geothermal steam high degree of contamination (corrosive SO2 and chloride salts) which cause erosion

1000-2000 times less CO2 than fossil fuel plant, smaller footprint

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12
Q

Transformers

A

Used to boost electricity up to 400,000 volts for efficient transmission. Converted back at substations
5-10% electricity generated lost in transmission network

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13
Q

Nuclear

A 
1*1 inch fuel = 1 tonne coal 
Greenhouse gas emission free (except during construction, fuel processing, transportation)
Nuclear weapon proliferation
Waste storage/reprocessing 
Minimises future dependencies on other fuels (coal from China, oil and gas from Russia)
Global political uncertainty over low grade waste storage
Public unease
Capital costs
Siting issues
Accidents 
Decommissioning
£92.50/mwhc
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14
Q

Trawsfynydd

A

470MW magnox reactor 1965-91 £103 million decommissioning will add £29.75/mwh to every mwh produced (69TWh during operations)

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15
Q

Wind turbine issues

A 
Environmental designated sites
Flicker
Noise
Bird strikes
Meteorlogical issues can damage system (ice and lightning)
2MW/km2
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16
Q

Wind turbine benefits

A 
20 year life
Easily decommissioned or taken down
Recyclable and sell-able steel
Financial markets now trust wind
£39/mwh
110GW available offshore wind farms
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17
Q

Biomass

A

Produces 14% world’s power
Uses: Power generation, biogas, biofuel, oil, biorefineries

Efficiencies lower than coal/oil due to lower operating temperatures

Drax reconfigured for coal and biomass burning
Negative economies of scale because of transportation component of fuel costs

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18
Q

Biorefinery flowpath

A

feedstock>pretreatment>cell wall break down>bio-transformation>purification>power generation

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19
Q

PV limiting factors

A

Inverter lifespan

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20
Q

Energy Trilemma

A

Energy security - leads to conflicts (e.g. Suez, Irag), energy equity (energy poverty affects the poorest), environmental sustainability (low carbon sources can be expensive)

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21
Q

Large scale electricity supply technology choice is made by investors

A

Adverse to risk
Require all technology licenses/consents to be in place
Highest profits chosen

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22
Q

Government incentives for low carbon energy

A

Financial: tax break, electricity price premium, carbon price, capital grants, low cost loans

Non-financial: automatic/preferential consent, support for env permits, liability waivers

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23
Q

LCOE

A

Levelized cost of energy - overall cost to supply electricity including capital, finance and operational costs

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24
Q

Capital grants

A

System installed for less than market price
Grant too high - waste of taxpayers money, sub optimal systems
Grant too low - slower uptake

25
Feed in Tariff
Fixed price for sale of electricity regardless of wholesale price Normally above market prices and index linked in UK from Apr 2010 - Mar 2019 for installations <5MW Bens: Low risk to investors, easy for small investors to see return Negs: Difficult for government to respond to changes in installation costs, UK solar high rate of return = waste taxpayers money
26
ROCs
Obligation for electricity suppliers to supply renewable electricity Tradeable Suppliers must purchase from generators at fixed cost Underpurchasing leads to penalties recycled to generators Bens: Guaranteed premium over wholesale prices, rewards generation Negs: Tech and location neutral - favours cheapest renewables
27
Contract for difference
Guaranteed fixed price for electricity (gov top up value below CfD, company pays back above) Round 1 UK Feb 2015 Round 2 UK Sep 2017 Bens: price certainty, rewards generation Negs: Location blind, technology agnostic
28
Grid strengthening
Renewables can overload rural/old networks (reverse flows) New renewables need to have reliable grid connections Developers pay for grid strengthening so not happening
29
Council help for renewables
Local planning of preferred areas (conflict minimisation) | Reduced planning cost and risk for developers
30
UKs average electricity demand
60GW
31
Severn Barrage
2GW
32
Grid balancing
Storage - electric cars, pumped storage Reducing demand - smart devices (fridges listening in to frequency fluctuations 50Hz in supply and turning down thermostat)
33
Importing energy
5 London sized blobs in transmeditarranean desert - 2000km long transmission line
34
Energy plan assumptions
1/8th UK devoted to production of energy crops for heating or combined H&P
35
CO2 tax
$100/tonne | High enough to encourage investment in renewables and research and efficiency measures
36
Carbon Pollution Government Solutions
Carbon tax, underwrite investment in carbon capture by guaranteeing they will redeem captured carbon certificates for $100/tonne, auction carbon pollution permits with a fixed minium price
37
Failures of a free market
``` Admission barrier (new green products entering the market) Small cost differences between old and green products ```
38
Plan D
Domestic - infrastructure present
39
Plan N
NIMBY
40
Plan L
Lib Dems
41
Plan G
Green
42
Plan E
Economics
43
Plan M
Middle
44
Renewable energy in the developing world
Weak grids, phone chargers (253mil sub-sahara), diesel reliance, wood and coal for heating and cooking SDG7 = ensure environmental sustainability Energy systems that support triple bottom line of (economy, society and environment) Energy demand in developing world rising 5% per year Developing world energy demand = depletion of fossil fuel resources, geopolitical problems, environmental problems IP for renewable energy owned by the Northern hemisphere Competitive advantage by building low carbon infrastructure from the beginning
45
Rural Electrification
Health (removal of smoky heat and light sources), equality, income (workable hours), education
46
Tidal stream power
1.7GW in development/planning
47
Ocean thermal energy conversion
Temp diff to generate electricity
48
Floating wind turbines
Full-scale since 09, mooring is the main challenge, stability is key
49
Tides
Range = height change Current = horizontal motions 2ms-1 is a reasonable value for current tidal turbines to be economical to operate EMEC in Orkney - world's first tidal and wave test site Tidal stream turbines - floating, surface-piercing, sea-bed pile Total tidal range capacity of 25-30GW Swansea lagoon - 360MW capacity
50
Wave energy
Variable with time Cable costs roughly linear with distance Power increases further offshore Attenuator, floating-point absorber, oscillating surge converter, wave overtopping device, oscillating water column Overconfidence in the speed of commercialisation led to unsuitable financial arrangements, no long-term funding schemes
51
Different types of ocean energy technologies
Tidal stream, tidal range, wave energy, offshore wind, osmosis, thermal,
52
Three principles of sustainability
Environment, economy and society
53
Triple bottom line
Sustainable solutions must protect the environment, produce a stable and profitable economy, support a healthy society
54
Transport
Roughly 1/3 energy use
55
Current UK energy
20% nuclear, 20% wind | All old nuclear retired by 2030, Hinkley ready, Angelsey nuclear power plant likely
56
Solar
Economies of scale, china producing lots, ethical sourcing of materials?
57
IPCC Recommendations
Reach net zero by 2050
58
Global issues
Governments only last 5 years, real difference cannot be made Advanced economies to be technology leaders Education necessary Who owns power plants and who is benefiting from them Community ownership Precautionary principle

January Revision (5 decks)

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