Electric Power Generation • Land plants • Buried, heated

Transcription

Electric Power Generation
Electric Power Generation: 51% Coal
U.S. Primary Energy Consumption by Source and Sector, 2007
• Land plants
• Buried, heated & compressed
• “Matured” into solid rock, almost all carbon
(Quadrillion Btu)
Source: EIA
Goal: Mechanical energy
! electrical energy
Waste heat
Coal bunker
Cooling tower
transfers waste
heat to
atmosphere
Turbine
Generator
Cooling loop
Stack
Condenser
Pulverizing
mill
Boiler
Toxic ash disposal
• 1978, Power Plant and Industrial Fuel Use Act
– Mandated conversion of oil burning power
plants to coal and natural gas
Source: DOE
• Advantages
• Disadvantages
– We have a lot of it
– Geographically diverse reserves
– Cheap
– Unacceptable greenhouse
gas emissions
Average plant: ~500 MW
3.7 M tons CO2/yr (600,000 cars)
10,000 tons SO2/yr
500 tons PM/yr
10,200 tons NOx/yr
720 tons CO/yr
220 tons VOC/yr
170 lb Mg/yr
225 lb Ar/yr
114 lb Pb
1
3.7 M tons CO2 /yr (600,000 cars)
10,000 tons SO2/yr
500 tons PM/yr
10,200 tons NOx/yr
gas emissions
720 tons CO/yr
– Toxic pollution
220 tons VOC/yr
• Acid rain
170 lb Mg/yr
225 lb Ar/yr
114 lb Pb
• Disadvantages
• Disadvantages
gas emissions
– Toxic pollution
• Acid rain
• Heavy metals
– Alteration of landscapes
3.7 M tons CO2 /yr (600,000 cars)
10,000 tons SO2/yr
500 tons PM/yr
10,200 tons NOx/yr
720 tons CO/yr
220 tons VOC/yr
170 lb Mg/yr
225 lb Ar/yr
114 lb Pb
Coal’s Future
Coal’s Future
1. Improve efficiency
2. Carbon capture
– Capture carbon dioxide when it’s burned
– Store liquefied CO2 > 800 m underground
Source: World Coal Institute: Coal Meeting the Climate Challenge
Electric Power Generation: 21% Nuclear
Nuclear Power
Nuclear’s Future
1. Licensing
2. Reprocessing
spent nuclear fuel
1. Mine naturally occurring uranium ore
- Uraninite, or pitchblende, UO2
US: 104 nuclear power plants, 21% electricity
World: 17% electricity
Source: NRC - Nuclear Research Council
Source: World Nuclear Association
2
Nuclear Power
Nuclear Power
1. Mine naturally occurring uranium ore
2. Produce U3 O8 “yellow cake”
3. Convert to UF6
4. Increase concentration (enrich) U235 to 3-5%
Bomb requires 90% U235
– Gaseous diffusion (Paducah, Kentucky)
– Gas centrifuge (none in US)
5. Create fuel rod assemblies
fissionable
- 4% U235
- 96% U238
nonfissionable
NRC
Nuclear Power
Nuclear Power
6. Nuclear fission of uranium and plutonium
7. Control chain reaction with neutron absorbing control rods
Lighter element,
fission products
neutron
U235
+ heat
Initial fuel rods!
Heat boils water
Produces steam
Spins turbines
Drives electric generator
Pu239
Pu240
Pu241
Nuclear Power
Nuclear Power
8. Spent fuel rods removed after 3-4 yr
8. Spent fuel rods removed after 3-4 yr
9. Temporary storage in water inside steel-lined, concrete
containers
- 20 tons/yr per plant
- 2,000 tons/yr
- 60,000 tons total in temporary storage
Initial fuel rods!
Pu239
Pu240
Pu241
Spent fuel rods!
10. Centralized, permanent containment
This step never actually realized
Source: Nuclear Energy Institute
3
Electric Power Generation: 17% Natural Gas
• Nonrenewable: Natural gas
– Mostly hydrocarbons in gas phase
found above reservoirs of crude oil
– CH4[g] + 2 O2[g] ! CO2[g] + 2 H2O[l] + 891 kJ
Phytoplankton
Zooplankton
Typical Composition
Refined and
sold separately
Refined and
sold separately
Methane
CH4
Ethane
C2H 6
70-90%
0-20%
Propane
C3H 8
Butane
C4H 10
Carbon Dioxide
CO2
0-8%
Oxygen
O2
0-0.2%
Nitrogen
N2
0-5%
Hydrogen sulfide
H2S
0-5%
Rare gases
A, He, Ne, Xe
trace
Oil and natural gas
migration
T, P
Maturation from heavy
oils to light gases
Source: Paleontological Research Institute
• Nonrenewable: Natural gas
– Mostly hydrocarbons in gas phase found above
reservoirs of crude oil (thermogenic)
• Renewable: Bacteria
– Methanogens give off methane during anaerobic
decomposition of organic matter
– Landfills (380 projects in the US)
– Livestock waste
– Human waste
4000 biogas
vehicles in Sweden!
Electric Power Generation: 9% renewable (7% hydro)
Hydropower’s Future
1. Large dams: stable or declining
2. Growth in small dams
20% world electricity (776 GW)
12% US (95,000 MW)
73% WA
Hydroelectric: rivers
1. Three Gorges Dam, China18.2 GW, 600’
• 115 meters thick at the bottom, 40 m at the top
• 1/ 9 China’s power (85 billion kwh/yr)
• $25 billion
• >1 million people relocated
Source: BBC
4
Source: BBC
Source: BBC
Source: BBC
Source: BBC
Source: BBC
Source: BBC
5
Dams: Columbia River Basin
4. Grand Coulee Dam
6.5 GW, 550’
Electric Power Generation: 9% renewable (<1% wind)
Electric Power Generation: 9% renewable (<1% solar)
Wind’s Future
1. 20% US
energy by 2030
Step 1: Make a semiconductor sandwich
Step 2: Sandwich creates an electric field
Step 3: Add photons
8.2
Step
MW, SunEdison,
4: Electrons
Alamosa, CO (electric current) flow
Electric Power Generation: 9% renewable (<1% solar)
Transportation
U.S. Primary Energy Consumption by Source and Sector, 2007
(Quadrillion Btu)
2 MW (3.5 m kWh) at Denver Int’l Airport
Source: EIA
6
Fuel economy
Transportation: 96% Petroleum
Phytoplankton
Zooplankton
Oil and gas
migration
T, P
Maturation from
heavy oils to light
gases
Source: Paleontological Research Institute
2008: 5,064,000
barrels/day
How much more oil ?!?!
Proven world reserves: 1,238 billion barrels
World demand: 85 million barrels/day
1,238,000/
85 = 41 year supply at current usage…
78% of remaining oil is in OPEC,
Organization of Petroleum Exporting Countries:
United Arab Emirates, Algeria, Indonesia, Iran, Iraq
Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, Venezuela
Source: British Petroleum
Tons per person, 2007
Transportation: 96% Petroleum . . . look for more
• Previously open areas
– 10 billion barrels proven reserves
– 86 billion barrel potential
• Now (as of 7/14/2008) open
– estimated 18 billion barrels (720 days worth)
Tons
Source: British Petroleum
7
Transportation: 96% Petroleum . . . look for more
Transportation: 96% Petroleum . . . use something else
• Oil Sand and Oil Shale (Heavy Oils)
– Formation similar to crude oil but less heat and pressure
– Oil shale contains kerogen
• Athabasca tar sands, Canada & Venezuela
• Potential 300 billion barrels recoverable each
– Oil sand contains bitumen
Transportation: use something else
Electricity
• ~50-100 miles before recharge needed
• 1995, Solectria Sunrise 238 miles on one charge
Transportation: 2% renewables
Biomass
• Plant materials or animal wastes
• converted into gaseous or liquid biofuels
Benfits of biofuels?
Biomass
• Plant materials or animal wastes
• converted into gaseous or liquid biofuels
Benfits of biofuels?
•
•
•
•
•
•
•
Home grow
Renewable
Reduced GHG emissions
Creates jobs, local tax revenue
Biodegradable, nontoxic (spills!)
Used in existing engines
Supports decentralized energy production
Ethanol
140,000 million gallons oil/yr
• Ethyl alcohol
• De-natured with 5% gasoline
• Use any high-carbrohydrate biomass
-Field corn (US), sugarcane (Brazil), switchgrass
-Cellulose, hemicellulose (under development)
8
140,000 million gallons oil/yr
Biodiesel
• Combine alcohol with any natural oil
– Alcohol: methanol or ethanol
– Oil: vegetable oil, animal fat or cooking grease, algae
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Electric Power Generation • Land plants • Buried, heated

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