Coal Gasification Using Integrated Gasification Combined ...

Integrated Coal Gasification Integrated Coal Gasification Combined Cycle (IGCC): Combined Cycle (IGCC): Environmental Impacts and Environmental Impacts and Policy ImplicationsPolicy Implications

Clean Air Task ForceOctober 27, 2004

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TopicsTopics

IGCC TechnologyEnvironmental PerformanceCostPolicy Implications

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IGCC: What is it?IGCC: What is it?

Chemical conversion of coal to synthetic gas for combustion in a modified gas turbine

Inherently cleaner process because:– Coal is not combusted.– Pollutants are removed with greater efficiency because

clean-up occurs while syngas volume is relatively small compared with flue gas.

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IGCC SchematicFeeds Gasification Gas Refining End-products

Syngas

Oxygen Electricity

CO2 Sequestration OptionSolids

SULFURRECOVERY

SULFUR /CO2

REMOVAL

H S2

HRSG Steam

Combustion Turbine

Syngas Chemicals

Hydrogen

Ammonia

MethanolCoalSyngas

Sulfur

REMOVAL

MERCURY

Mercury

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Tampa Electric – Polk Power Station.

250 MW – operating since 1996

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PC PlantPC Plant-- chemical plant at the back endchemical plant at the back end

Fuel

Bottom Ash

Fly Ash

FGD Byproducts and Waste

Stack Emissions

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SO2 EmissionsSO2 Emissions

Commercial technology can remove SO2 to trace levels.2 ppm (about 0.14 lb/MWh) is being achieved at new Japanese IGCC (heavy oil) unit (after 6 months of operation).0.15 lb/MWh has been demonstrated on a sustained basis at the ELCOGAS (coal) plant in Spain.Proposed new US IGCC seeking ~.30 lb/MWhSO2 permit limits

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SO2 EmissionsSO2 EmissionsCoal Plant SO2 Emission Rates

Pounds per MWH

10.272

0.934

0.3970.144

0.00

2.00

4.00

6.00

8.00

10.00

12.00

All Coal in 2002 Average of The Best 38Coal Plants

Best Coal Plant in 2002 New Japanese Plant

Lbs

per M

WH

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NOx EmissionsNOx Emissions

Potential issue: SCR operation may cause heat recovery steam generator foulingSCR at Japan IGCC achieving 2 ppm levels, or about 0.10 lb/MWh after 6 months of operation.Relatively low rates - 15 ppm permit limit, actual emissions 8 - 11 ppm at Polk without SCR.Proposed US IGCC plants seeking ~.5 lb/MWh NOx permit limit (no SCR).GE and Siemans are working to lower syngas NOx emissions rates to <2ppm without SCR

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NOx EmissionsNOx EmissionsCoal Plant NOx Emission Rates

Pounds per MWH

4.294

1.320

0.584

0.099

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

All Coal Plants in 2002 Average of the Best 30Coal Plants

Best Coal Plant in 2002 New Japanese Plant

Lbs

per M

WH

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Solid waste and water useSolid waste and water use

Solid Wastes– Less Volume: IGCC produce about half the solid

wastes of conventional coal plants.– Better Form: IGCC solid wastes are less likely to leach

toxic metals than fly ash from conventional coal plants because IGCC ash melts and is vitrified (encased in a glass-like substance).

Water Use– Less Water: IGCC units use 20%-50% less water than

conventional coal plants and can utilize dry cooling to minimize water use.

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Carbon dioxideCarbon dioxide

Up to 100% of the carbon in syngas can be captured at IGCC plants with commercially available technology.

Carbon capture at IGCC plants is significantly easier and much more economic than at conventional pulverized coal plants and more economic on a $/ton basis than at natural gas plants.

Even without carbon capture and sequestration, IGCC plants are more efficient than conventional coal plants and emit less CO2.

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IGCC costs are close to IGCC costs are close to conventional coal plantsconventional coal plants

IGCC may cost slightly more than convention plants without carbon capture and sequestration (CCS) but costs much less when carbon is reduced.

Cost of Electricity in $/MWh

Conventional Coal IGCC

ConventionalCoal IGCC

Bituminous 46.6 45.8-48.3 75.4 61-67

Subbituminous 44 48-54 64-97 61

Without CCS With CCS

Source: EPRI, 2004

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New IGCC ProposalsNew IGCC Proposals

Significant new IGCC proposals have been announced in the last year:

– AEP:1000 MW IGCC– Cinergy: 600 MW IGCC– ArcLight Capital: 500 MW IGCC

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Policy Train WreckPolicy Train Wreck

IGCC proposals are becoming more common, but why build an IGCC if you can get a permit with much higher emission rates for a conventional coal plant?

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IllinoisIllinois-- Pending Permit Pending Permit ApplicationsApplications

Peabody, 1500 MW PC

ArcLight,544 MW IGCC & Methane Production

SO2 .182 lb/MMBtu

.034 lb/MMBtu

NOx .08 lb/MMBtu

.059 lb/MMBtu

Mercury .14 Tons/yr .0105 Tons/yr

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WisconsinWisconsin-- Elm RoadElm Road

SCPC IGCC% Increase due to SCPC

Sulfur Dioxide 0.15 0.03 400%Nitrogen Oxide 0.07 0.07 0%Carbon Monoxide 0.12 0.03 300%VOC 0.0035 0.0017 106%Hg 1.1E-06 5.6E-07 100%PM 0.018 0.011 64%Sulfuric Acid Mist 0.01 0.0005 1900%Notes: Elm Road Wisconsin permit limits issued by WDNR January 2004, expressed in lb/MMBtu. This air permit is a good comparison of IGCC and SCPC because it is for both technologies at the same site using the same Pittsburgh #8 bituminous coal.

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Solution to the Policy Train Solution to the Policy Train WreckWreck1. Require conventional coal plants to

evaluate IGCC in their BACT analysis

2. Insist on proper evaluation

3. Find IGCC as BACT when the specific situation merits that determination

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Best Available Control Technology (BACT) Best Available Control Technology (BACT) and IGCCand IGCC

If a conventional coal plant is proposed, should IGCC be evaluated as an alternative option?

– StatesYes: Illinois, Montana, New MexicoNo: Wisconsin, West Virginia, UtahUndecided: Many states

– Federal• May issue an opinion through permit appeal decision.

Have been reluctant to decide in other forums.

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IGCC as BACTIGCC as BACT

Argument that IGCC is “redefining the source” do not apply because:– IGCC is an “inherently lower emitting

technology”– Legislative history of “innovative

combustion technique” identifies coal gasification as one example.

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Observations and Observations and RecommendationsRecommendations

More IGCC plants are being proposed than in the past.IGCC plants are vastly cleaner than conventional coal-fired power plants.Costs of IGCC are close to that of conventional coal-fired power plants.Regulatory crossroads- Is IGCC BACT for producing electricity from coal?

You’ll never know if your state’s air permit applications don’t compare IGCC to conventional coal plants AND do the comparison accurately!!!

STAPPA/ALAPCO should urge USEPA to require IGCC be evaluated in BACT analysis for conventional coal plants