The Development of Clean Coal Technology in the US
Jhih-Shyang Shih Fellow
Resources for the Future
CTCI Foundation Environmental & Energy Convention Taipei, Taiwan, ROC
January 16, 2007
Overview
• Coal and Electricity
– Electricity Demand – Electricity Supply
• Strategic Drivers for Clean Coal
– Economics, Energy Security and Environment
• Clean Coal Technology
– Coal Liquefaction, Combustion Technology, Carbon Capture, and Emission Control Technology
• Cost and Performance Comparison
• Policies/Programs and CCT
• Summary
Coal and Electricity
US Electric Power Generation (2005)
Coal 49.7%
Petroleum 3.0%
Natural Gas 18.7%
Other Gases 0.4%
Nuclear 19.3%
Hydroelectric 6.5%
Other Renewables 2.3%
Others 0.1%
Data Source: EIA, Electric Power Annual
Total = 4,055 Billion kWh
Annual Electricity Sales by Sector (billion kWh)
0 500 1000 1500 2000 2500
1970 1980 1990 2000 2010 2020 2030 2040
Commercial Residential
Industrial
History Projections
Electricity Generation by Fuel 2005 and 2030 (billion kWh)
0 500 1000 1500 2000 2500 3000 3500 4000
Coal Nuclear Natural Gas Renewables Petroleum
2005 2030
Data Source: AEO 2006
Coal Generation Demand by 2030
• 154 gigawatts of new coal capacity are projected to be needed (EIA).
• 153 new coal-fired plants (93 gigawatts) are
under consideration.
Strategic Drivers for Clean Coal
• what are the drivers for coal?
• why do we need clean coal?
Economics: Coal Market and Price
• Coal is readily available from a wide variety of sources in a well-supplied worldwide market.
• Coal prices have historically been lower and more stable than oil and gas prices.
• Coal is likely to remain the most affordable fuel for power generation in many developing and industrialized countries for several decades.
Source: World Coal Institute
Energy Security: Coal Reserve
• Total recoverable reserves of coal around the world are estimated at 1,001 billion tons—enough to last
approximately 180 years
(compared to 41 years for oil and 65 years for gas).
• 67 percent of the world’s
recoverable reserves are located in four countries: the United States (27 percent), Russia (17 percent), China (13 percent), and India (10 percent).
Source: World Coal Institute
Environment
• Coal Use & the Environment
– Coal is the major emitter of CO2, a greenhouse gas.
– Coal is also an emitter of particulate matters, SOx and NOx, and mercury.
• Coal Mining & the Environment
– land disturbance, mine subsidence, acid mine drainage, dust & noise pollution.
– Rehabilitation.
Global Warming
Challenges of Power Generation Using Coal
• To continue to supply secure and affordable electricity in the face of growing demand.
• To provide more efficient energy, reducing pollution, and increasing the emphasis on environmental sustainability.
The electricity is a major contributor to
economic and social development. However,
electricity generation using coal faces many
challenges in this century:
Clean Coal Technology
Clean Coal Technology
• Coal Liquefaction
– Coal to Liquid (CTL)
• Combustion Technology
– Pulverized Coal (PC) combustion – Advanced PC technology
• Supercritical PC (SCPC) combustion
• Ultra-supercritical PC (USCPC) combustion – Fluidized Bed Combustion (FBC)
– Integrated Gasification Combined Cycle (IGCC)
• Carbon Capture
• Emissions Control Technology
Coal Liquefaction
• Coal liquefaction is the conversion of coal into a synthetic oil in order to supplement natural
sources of petroleum.
• Coal liquefaction and heavy oil refining were potentially the two largest sources of transportation fuels that could be used to mitigate the peaking of conventional oil.
Pulverized Coal (PC) Combustion
Coal-fired electricity generation today normally uses conventional subcritical pulverized coal (PC)
Source: IEA
Advanced PC Combustion Technology
• Two types: supercritical (SC) & ultra-supercritical (USC)
• Power plants operate at high temperatures and pressures. This results in higher efficiencies – up to 46% for supercritical and 50% for ultra-
supercritical
• Lower coal consumption and pollutant emissions than conventional PC plant
• Advancements in materials, controls and
temperature mixing led to improved performance
and reliability
Pulverized Coal Technology
7,757 Btu/kWh
44%
5,500 psig Ultra-
Supercritical
9,300 Btu/kWh
37%
3,500 psig Supercritical
9,751 Btu/kWh
35%
2,400 psig Subcritical
Heatrate HHV
Net Energy Efficiency Conditions
Source: Supercritical Plant Overview
Subcritical vs. Supercritical
117 Units 1,338 Units
US Operating Units
Lower Base
Fuel Cost
0-2% Higher Base
Non-Fuel O&M
1-6% Higher Base
Plant Capital Cost
0-9% Higher Base
Boiler Capital Cost
36-44% HHV 34-37% HHV
Heatrate Efficiency
Supercritical Subcritical
Source: Supercritical Plant Overview
Fluidized-Bed Combustion (FBC)
• Fluidized beds suspend solid fuels on upward-
blowing jets of air during the combustion process.
• The technology burns fuel at temperatures of
1,400 to 1,700 degrees F, well below the threshold where nitrogen oxides form.
• Limestone can be added to control sulfur with 95% removal rate.
• Greater fuel flexibility.
• Currently, 104 Boilers-8,900 MW in operation and
up to 320 MW size range offered.
Integrated Gasification Combined Cycle (IGCC)
• Coal and other hydrocarbons have been gasified for the production of chemicals, fertilizers, and synthetic fuels for more than half a century.
• 117 plants with 385 gasifiers in operation in 2004. These facilities produce mostly chemicals (37%), gas (36%) or power (19%).
• Current IGCC power technology applications focus on producing CO rich syngas that can be burned in turbines.
• Future IGCC technologies maybe developed to produce hydrogen rich syngas with maximum carbon capture ( “zero emission” IGCC).
Planned Coal-Fired Power Plants as of 2006
No. of Plants
23
13
2
28
0 5 10 15 20 25 30
CFB Supercritical Ultra-Supercritical Gasification
Data Source: NETL
Carbon Capture
• There are a number of options for the capture of CO
2:
– Post-combustion: CO
2is captured from the flue gas at atmospheric pressure and at low
concentration.
– Pre-combustion: CO
2can be captured from a syngas (coming out of the coal gasification reactor) before it is mixed with air in a
combustion turbine.
Emissions Control Technology
• In the last three decades, control technologies have been developed to capture conventional pollutants contained in the exhaust systems from coal combustion.
• Pollutants that can be removed include sulfur oxides, nitrogen oxides, and particulates.
• Mercury has been regulated since March 15, 2005.
• The technologies that can be utilized to remove these pollutants are:
– Sulfur Oxides: Wet and Dry Flue Gas Desulfurization Plant
– Nitrogen Oxides: Low NOx burners, Post Combustion Catalytic Reduction Systems
– Particulates: Electrostatic Precipitator, Fabric Filters – Mercury: Activated Carbon Injection Systems
Mercury Emissions
Hg Speciation by Coal Rank
Mercury Control
• Oxidized mercury: water soluble, high removal with FGD
• Elemental mercury: non-water soluble, can be removed by activated carbon injection
• Particulate mercury: can be removed by
existing particulate controls
Performance and Cost
HHV Efficiency (%)
39
31.5
36.3
23.9
38.5
26.9
50.6
43.4
0 10 20 30 40 50 60
IGCC IGCC w CO2
Sub PC Sub PC w CO2
Super PC Super PC w CO2
NGCC NGCC w CO2 Source: NETL
32
Total Capital Requirement ($/kW, 2006 dollars)
1692
2245
1474
2626
1508
2635
568
988
0 500 1000 1500 2000 2500 3000
IGCC IGCC w CO2
Sub PC Sub PC w CO2
Super PC Super PC w CO2
NGCC NGCC w CO2 Source: NETL
Cost of Electricity
(cents/kWh, 2006 dollars)
5.48
7.13
4.99
8.63
4.97
8.35
6.75
8.99
0 1 2 3 4 5 6 7 8 9 10
IGCC IGCC w CO2
Sub PC Sub PC w CO2
Super PC Super PC w CO2
NGCC NGCC w CO2
Performance and Cost of Hg Emissions Control
• Mercury removal performance has been observed to vary between 70% and 98% using sorbent
technology.
• The range of sorbent consumption costs is quite large, depending on the combustion technology.
• According to an NETL report, the estimated cost of mercury removal from an IGCC plant was
$3,412 per pound of mercury, compare to $37,800
per pound of mercury removal from a PC plant.
Policies/Programs and CCT
Relevant Policies
• Energy Policy Act of 2005
– Provide many incentives: authorization, tax incentives and loan guarantees. The Energy Policy Act of 2005 (EPAct) authorized the Department of Treasury to provide tax credits as incentives to move advanced technologies to the marketplace. EPAct focuses on
clean energy, efficient energy use, energy conservation, and advanced technologies.
– Energy and Treasury Secretaries announce the award of
$1 billion in Tax Credits to Promote Clean Coal Power Generation (11/30/2006).
Relevant Policies
• Clean Air Act
– Clean Air Mercury Rule (CAMR) –It is a mercury cap-and-trade program affecting new and existing coal fired units greater than 25 MW. Phase I starts in 2010 and has a national cap of 38 TPY; Phase II starts in 2018 and has a national cap of 15 TPY. Electricity generators are expected to retrofit coal-fired capacity with ACI
technology in order to comply with the CAMR caps.
– Clean Air Interstate Rule (CAIR) –It contains an
annual SO2 cap-and-trade program, as well as an annual and Ozone Season NOx cap-and-trade program, for the DC and 28 eastern and midwestern states. Power
companies are projected to add FGD and SCR to comply with State and Federal initiatives
Relevant Policies
• Climate Change
– Regional Greenhouse Gas Initiative (RGGI) is a regional initiative by states in the
Northeastern United States region to reduce greenhouse gas emissions.
– The RGGI is designing a cap and trade program for emissions from power plants.
– In August 2005, the RGGI staff working group proposed an emissions reduction program that would start in 2009 and lead to a stabilization of emissions at an average of 2002-2004 levels by 2015.
– California Governor’s Executive Order # S-3-05 (June 1, 2005) and AB 32, the California Global Warming Solutions Act of 2006.
Relevant Programs
• Clean Coal Technology Program (1986-93)
– 38 projects (18 state)
– Total investment: $5.2 billion
– Federal Government: $1.8 billion (34%) – Industry/States: $3.5 billion (66%)
• Power Plant Improvement Initiative (2001)
• Clean Coal Power Initiative (2002)
• FutureGen Initiative (2006)
Some successful projects under 1986-1993 Clean Coal Technology Program
