coal: an old source facing new challenges daniel cohan rice university october 4, 2014
TRANSCRIPT
![Page 1: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/1.jpg)
Coal: An Old Source Facing New Challenges
Daniel Cohan
Rice University
October 4, 2014
![Page 2: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/2.jpg)
Outline
• Overview of coal and its use• Emissions from coal• Controlling emissions from coal• Other impacts of coal• Costs of coal
2
![Page 3: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/3.jpg)
Overview of Coal and its Use
![Page 4: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/4.jpg)
4
How Coal Forms
• Plants die in swamp forests and are buried by sediment as peat
• Heat and pressure expel water and gases
• Coal becomes more carbon and energy rich over millions of years
Graphic from Univ of Kentucky
![Page 5: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/5.jpg)
5
![Page 6: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/6.jpg)
6
Western coals becoming increasingly prevalent
• Thick seams in West for large-scale mining
• Appalachian coals heavily utilized before, most accessible reserves already tapped
• Western coals have lower sulfur content, lower price– Transportation costs,
bottlenecks are issueUS EIA, AEO 2012
![Page 7: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/7.jpg)
Powder River Basin Coal supplies many TX power plants
7
http://www.wildearthguardians.org/images/content/pagebuilder/Powder_River_Basin_distribution_legend-2.jpg
![Page 8: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/8.jpg)
8
U.S. uses 1,045,878,000 tons of coal for electric generation each year• 3.5 tons/person/year (~50 times
our weight)
100 tons1 ton
360 tons12 tons
![Page 9: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/9.jpg)
9
U.S. Coal Use Trends
• Historically, large use by industry, homes, transportation
• Now power plants predominate
US EIA, AEO 2006
![Page 10: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/10.jpg)
Coal supplies 34% of electricity for the Texas ERCOT grid
10
Natural gas45%
Coal34%
Nuclear12%
Wind9%
Other0%
Electricity Generation (MWh) in ERCOT, 2012
![Page 11: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/11.jpg)
Coal is big share of US electricity capacity, but most growth is natural gas & renewables
11
![Page 12: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/12.jpg)
Most U.S. coal-fired electricity is from decades-old power plants
12
Cohan and Douglass, 2011
![Page 13: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/13.jpg)
Emissions from Coal
![Page 14: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/14.jpg)
14
IPCC
![Page 15: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/15.jpg)
Projected climate change depends on CO2 emissions
15
IPCC, WGI SPM, 2013
![Page 16: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/16.jpg)
Electricity Generation: Biggest source of greenhouse gases in U.S.
16
![Page 17: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/17.jpg)
Highest CO2 emissions from coal(This is life cycle CO2equivalent basis, so
includes CH4 leaks, etc)
17
Greenhouse gas impact per kWh:Coal >> Natural gas >> Solar, biomass, wind, nuclear
Weisser, “A guide to life-cycle greenhouse gas emissions from electric supply technologies.” Energy, 2007
![Page 18: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/18.jpg)
Old coal plants emit far more NOx than other options in Texas
18-
0.5
1.0
1.5
2.0
2.5
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
NO
x E
mis
sion
Rat
e (l
b/M
Wh
)
TXU legacy coal
Other old coal
New coal
10 cleanest old coal
Natural gas
Cohan, 2013
Emissions from Texas power plants
![Page 19: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/19.jpg)
NOx contributes to excess ozone in Texas cities (standard is 75 ppb)
19
0
20
40
60
80
100
120
8-h
r O
zon
e D
esig
n V
alu
e (p
pb
)
Houston-Galveston-Brazoria (88)
Dallas-Fort Worth (87)
Beaumont-Port Arthur (80)
San Antonio (80)
Tyler-Longview-Marshall (79)
Waco (75)
Austin-Round Rock (74)
Corpus Christi-Victoria (72)
El Paso (72)
Cohan, 2013
![Page 20: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/20.jpg)
20
Ground-level Ozone Impacts
• Health effects– Strong oxidant, irritates lungs– Linked to asthma and other
respiratory illnesses– Recently linked to mortality
• Damage to vegetation & crops• Greenhouse gas• Non-attainment of EPA standards
![Page 21: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/21.jpg)
Old coal plants emit far more SO2 than other options in Texas
21-
2.0
4.0
6.0
8.0
10.0
12.0
14.0
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
SO2
Em
issi
on R
ate
(lb/M
Wh)
TXU legacy coal
Other old coal
New coal
10 cleanest old coal
Natural gas
Cohan, 2013
Emissions from Texas power plants
![Page 22: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/22.jpg)
22
SO2 contributes to fine particulate matter
• Particulate matter: airborne particles composed of a variety of chemical compounds
• Particulate matter is likely the leading cause of illness and mortality from air pollution
![Page 23: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/23.jpg)
Controlling emissions from coal-fired electricity
![Page 24: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/24.jpg)
Timeline of US cap-and-trade policies for air pollutants
http://www.epa.gov/airmarkets/progress/ARPCAIR10_01.html
![Page 25: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/25.jpg)
25
U.S. Power Plant Emissions Trends
NOx Emissions SO2 Emissions
http://www.epa.gov/airmarkt/progress/datatrends/index.html
![Page 26: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/26.jpg)
US EPA Policies for CO2 from Power Plants
• Historically, CO2 was not regulated
• 2007: Supreme Court in Massachusetts v. EPA ruled Clean Air Act can cover CO2
• 2013: Proposed New Source Performance Standards of 1000-1100 lb CO2/MWh
– Attained by new natural gas plants– Would require partial capture of CO2 from coal
• 2014: Proposed Clean Power Plan, with CO2 targets for each state– For Texas: 39% reduction by 2030 26
![Page 27: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/27.jpg)
Clean Power Plan CO2 Reduction Targets
27
![Page 28: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/28.jpg)
US Power Plant CO2 Trends
28
http://www.epa.gov/airmarkt/progress/datatrends/index.html
![Page 29: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/29.jpg)
29
Power Plant NOx Control:Selective Catalytic Reduction (SCR)
• Ammonia is injected after boiler to convert NOx to N2 and water– Requires catalyst– Specific temperature
range
• ~85% NOx reduction
29
www.de-nox.com
![Page 30: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/30.jpg)
Flue Gas Desulfurization (“Wet Scrubber”) for SO2
US DOE National Energy Technology Laboratory
![Page 31: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/31.jpg)
Rainfall Acidity, 1994
![Page 32: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/32.jpg)
Rainfall Acidity, 2009(Note the reductions in acidity in regions where coal is heavily used for electricity; results from SO2 & NOx controls under Acid Rain Program)
![Page 33: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/33.jpg)
Post-combustion carbon capture
33
FIGURE 12.1 Flowsheet of the monoethanolamine (MEA) process for CO2 capture.
Fay & Golomb textbook
• Reaction of liquid solvent MEA with CO2 • C2H4OHNH2 (“MEA”) + H2O + CO2 ↔ C2H4OHNH3
+ + HCO3-
• Need 1 mole MEA per mole CO2 captured• Huge material flows: 400 kg/s MEA for 500MW plant
Forward Reaction @ 40-65°C (flue gas must be cooled)
Reverse Reaction @ 100-120°C (needs steam; hurts efficiency)
![Page 34: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/34.jpg)
34
CO2 Transport
• Pipelines– Some CO2 pipelines already exist for
enhanced oilfield recovery– Similar impacts as other hydrocarbon pipelines
• Ships– CO2 could be liquefied for ship transport
• Road or rail– Probably not cost-effective
![Page 35: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/35.jpg)
35
Methods for storing CO2 in deep underground geological formations
SRCCS Figure TS-7
![Page 36: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/36.jpg)
36
Global distribution of large stationary sources of CO2
Prospective areas in sedimentary basins where suitable saline formations, oil or gas fields, or coal beds may be found.
SRCCS Figure TS-2b
![Page 37: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/37.jpg)
37
Geological Storage Capacity
• For comparison, global anthropogenic emissions are about 28 GtCO2/year
IPCC, 2005
![Page 38: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/38.jpg)
Cost of CCS vs. other CO2 control options
38
![Page 39: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/39.jpg)
Coal Impacts beyond Air and Climate
![Page 40: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/40.jpg)
40
Mountaintop Removal Mining• In much of Appalachia, coal seams may
be hundreds of feet beneath surface• 500 feet or more of a mountain summit
may be removed to access coal
![Page 41: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/41.jpg)
Coal Ash Pond Spill, Kingston (TN) Power Plant, December 2008
Associated Press41
![Page 42: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/42.jpg)
Ash from Coal Power Plants
42
![Page 43: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/43.jpg)
Coal Ash• Ash from coal combustion: 10% of original
volume of coal (U.S. EPA)– Fly ash (74%): Mixed with exhaust gas;
captured by various technologies– Bottom ash (20%): Large, settles to bottom– Boiler slag (6%): Ash that melts by heat
• 1,300 coal ash dumps in U.S.– Mercury, lead, arsenic, and selenium in ash– Lack of federal regulation– $5-11 billion/year estimated clean-up costs
N.Y. Times, “Hundreds of Coal Ash Dumps Lack Regulation,” 1/6/200943
![Page 44: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/44.jpg)
Solid Wastes from Coal Power Plants
• Coal combustion generates ~129 million tons/year of wastes in US; ~35% reused
US EPA Coal Combustion Products Partnership
44
![Page 45: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/45.jpg)
Cost of Coal Electricity
![Page 46: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/46.jpg)
New coal costs more than gas, wind, or geothermal; with carbon capture, it costs more than solar
![Page 47: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/47.jpg)
Alternatives to coal in Texas
47
Cost1
Cost with incentives2
Cost with incentives + $25/ton CO2 3
SO2 4
(lb)
NOx 5
(lb) CO2 6
(lb) Hg 7
(10-5 lb) Water use 8
(gal)
Legacy coal 2011 $39.63 $39.63 $66.34 9.18 1.48 2,137 8.9 300 Coal with UBS retrofits 9
$42.89 $42.89 $70.02 4.36 1.23 2,170 0.9 309
Coal with SCRs 10 $45.29 $45.29 $72.42 4.36 0.59 2,170 0.9 309 Natural gas $65.90 $65.90 $79.51 0.01 0.36 1,089 0.0 270 Geothermal $76.10-
$88.20 $65.10- $77.20
$65.65- $77.75
0.17 0.00 44 0.0 5
Coastal wind $51.00-$83.40
$40.00- $72.40
$40.00- $72.40
0.00 0.00 0 0.0 1
Solar $140.30 $77.90-$101.18
$77.90- $101.18
0.00 0.00 0 0.0 26
Energy efficiency $35.00 $35.00 $35.00 0.00 0.00 0 0.0 0
Cohan, 2013
Costs per MWh generated
![Page 48: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/48.jpg)
Externality costs of coal(National Research Council, 2009)
• 3.2 cents/kWh due to health and other impacts of air pollution– 1.7 cents/kWh by 2030 as emissions are cut– Natural gas impacts are ~0.2 cents/kWh– Other studies estimate much higher impacts from coal
• Wide uncertainty on climate impacts (up to 10 cents/kWh)
• Additional impacts from coal mines and transport
48
![Page 49: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/49.jpg)
Projections of coal use depend on climate policy
49
GHG15 scenario: US sets CO2 emission price, rising to $44/ton by 2035
US EIA Annual Energy Outlook 2012
![Page 50: Coal: An Old Source Facing New Challenges Daniel Cohan Rice University October 4, 2014](https://reader035.vdocuments.site/reader035/viewer/2022062516/56649ddd5503460f94ad592d/html5/thumbnails/50.jpg)
Summary of challenges to coal• Old coal plants provide affordable
electricity, but:– Need to control NOx, SO2, and mercury
– Retrofit carbon capture is very expensive– EPA Clean Power Plan will require CO2 cuts
• New coal plants aren’t cost competitive with natural gas or some renewables– Need carbon capture to meet EPA’s proposed
New Source Performance Standards• Impacts to air, climate, land, and water
50