14 Evaluating Supplemental Fuels using Vista …mydocs.epri.com/docs/publicmeetingmaterials/1104/73NXUF...All rights reserved. 6 Building On - Identifying Costs 0 50 100 150 200 250

Evaluating Supplemental Fuels Using the Vista Program

Dave O’Connor, EPRIKen Nowling, Black & Veatch

Biomass Torrefaction WorkshopApril 14, 2011

2© 2011 Electric Power Research Institute, Inc. All rights reserved.

Overview

•Why Does Quality Matter?

–Why isn’t better always better?

• Introduction to the Vista model

•Biomass Cofiring Case Study

•Cofiring Analysis Case Study

•Conclusions


Minimizing Total Generation Costs

Clean Ash Content Raw

Cos

t

Cost of CleanerCoalAsh RelatedGenerating CostTotal GeneratingCost

Imagine similar curves for each type of emission and credits.

Then add all of them together…!


EPRI VistaTM

Predicts Fuel-Related Generating Costs and Operating Impacts of Alternate Fuels

Evaluating Unit-Fuel Impacts


Vista Core - Predicting Performance

PerformanceHistory

PlantConfiguration Fuel

Quality Predict Performance & Generation Costs Based on Available Design

and Performance Data


Building On - Identifying Costs

0

50

100

150

200

250

300

Allowances (SO2, NOX, Hg, CO2)

Waste Disposal/Sales Bottom/Fly Ash Pulverizer Rejects Gypsum

Replacement PowerEquipment Limitations (Derates)Equipment Forced Outage RatesAuxiliary Power Requirements

Consumables & MaintenanceFuel RequirementsSCR, FGD, ESP AdditiveHg and SO3 Removal AdditivesFixative

Annual Generation Costs


Generation from Better, More Expensive Coal Can Be Cost-Effective

Cost

Raw Coal Clean Coal

Consumables MaintenanceWaste Disposal Lost Generation


Vista Boiler Model


Basic Analysis Results - Example

• Vista results arepresented in an Excelspreadsheet, whichis easily customizableby using tag-driventemplates (similarto PI).

• More than 1,000results available foreach fuel case whichis evaluated.


Two Case Studies Using Vista Model

• Vista Program Capabilities for Analysis of Biomass Co-Firing, 1020682– Published February 2010– Available at no cost to the public at EPRI.com

• Engineering and Economic Evaluation of Biomass Power Plants, 101972– Includes new plants, repowered plants, and cofiring– Published December 2010– Available to P84 funders at no additional cost– Available to non-funders for a fee


Basic Vista Biomass Co-Firing Capabilities

• Vista can evaluate all of the following biomass scenarios.– Co-milling: biomass fuel(s) mixed with coal at the reclaim

point, or fed into the mill fuel stream separately.– Direct injection: biomass fuel is processed and sent

directly to the boiler, bypassing the mills (or tied-in to mill coal pipes).

– Gasification: biomass is gasified (or already a gas) and co-fired in the boiler.

– Other: liquid biomass (B99, tall oil, etc.) injected directly into the boiler.

– Combined: co-milling + direct injection, etc.


“Vista Program Capabilities…”Details

10%10%Biogas (40% Moisture Wood Base)

Gasification Cases

3% + 10%3% + 10%Pelletized Straw

Co-Milling + Direct Injection

10%10%Bagasse

10%10%Arundo Donax Straw

10%10%Miscanthus Straw

10%10%Utility Tree Trimmings

10%10%Raw Wood, 40% Moisture

Direct Injection Cases

3%3%Sewage Sludge

5%5%Pelletized Straw

10%10%Torrefied Wood5%5%Sawdust/Sawmill Residue

3%3%Raw Wood, 20% Moisture

Co-milling Cases

PRB UnitEastern UnitBiomass type, co-firing method, and heat input.

• Examined two 250MW conceptual units with current emissions control equipment (SCR and scrubber) co-firing biomass at different input levels.– Fuel quality and

performance sensitivity analyses, capital improvement studies, and use with test burns covered.


Biomass Parameters

10.0129.2710.8131.9423.96Oxygen, %

1.781.662.743.182.38Ash, %

6.2125.6840.0020.0040.00Moisture, %

0.000.010.010.030.02Chlorine, %**

0.010.010.040.090.07Sulfur, %

0.560.012.750.830.62Nitrogen, %

3.194.394.553.682.76Hydrogen, %

78.2439.0039.1040.2430.18Carbon, %

Ultimate Analysis*

72.358.4111.1410.908.17Fixed Carbon, %

19.6664.2546.1265.9249.44Volatile Matter, %

1.781.662.743.182.38Ash, %

6.2125.6840.0020.0040.00Moisture, %

Proximate Analysis*

12,7596,3584,3006,9355,201

Higher Heating Value,Btu/lbm

Torrefied WoodSawdust/Sawmill Residue

Utility Tree Trimmings

Raw Wood, 20% Moisture

Raw Wood, 40% Moisture

Fuel Quality Parameter


Key Cost Assumptions

• Delivered Eastern Unit Fuel Costs--200 cents/MBtu

• Delivered PRB Unit Fuel Cost--130 cents/MBtu

• Biomass Delivered Fuel Cost--300 cents/MBtu

• Fly Ash Disposal Cost--$10/ton

• Fly Ash Sales Price--$7.50/ton

• SCR Reagent Cost--$200/ton

• Limestone Cost (Scrubber)--$33/ton

• Scrubber Gypsum Sales Price--$12.50/ton

• SO2 Allowance Cost--$100/ton

• NOX Allowance Cost--$500/ton

• CO2 Emissions Cost--$15/ton

• Mercury Emissions Cost--$1,450/oz.

• Baseline Net Capacity Factor--75%

• Baseline Equivalent Availability Factor--85%

Very favorable assumptions for torrefied wood


Eastern Coal Unit—Engineering Results

6.096.746.00Unit Opacity, %

0.030.030.03NOX Emissions, lbm/MBtu

0.320.300.32Boiler NOX, lbm/MBtu

0.150.160.17SO2 Emissions, lbm/MBtu

NoneMill MotorNoneMost Limiting Item

0.0011.720.00Potential Derate, MW

LowLowLowFouling Potential

Low/MedLow/MedLowSlagging Potential

6.4-0.85.1Mill Capacity Margin, %

5.03.84.0Induced Draft Fan Margin, %

4.93.63.4Forced Draft Fan Margin, %

8.668.730.00Biomass Burn Rate, ton/hr

81.4786.4190.77Coal Burn Rate, ton/hr

221.0111.00.0Biomass Heat Input, MBtu/hr

2,209.92,220.62,216.1Total Heat Input, MBtu/hr

9,285.09,337.99,291.7NPHR, Btu/kWh

6.325.485.79Fly ash LOI, %

87.6187.1987.38Boiler Efficiency, %

238.01237.81238.50Net Power, MW

Full-Load Results

Torrefied Wood

Sawdust/Sawmill ResidueCoal

Performance Parameter


Eastern Coal Unit—Focus on Technical Results



NoneMill MotorNoneMost Limiting Item


6.4-0.85.1Mill Capacity Margin, %



221.0111.00.0Biomass Heat Input, MBtu/hr

2,209.92,220.62,216.1Total Heat Input, MBtu/hr

9,285.09,337.99,291.7NPHR, Btu/kWh

238.01237.81238.50Net Power, MW

Full-Load Results

Torrefied Wood




Eastern Unit—Annual Summary

85.1084.5385.00Equivalent Availability, %

74.9374.9575.00Net Capacity Factor, %

51.955.257.0Mercury Emissions, lbm/year

1,400,2271,482,0211,556,580

Non-renewable CO2 Emissions, ton/year

1,566,0801,565,1901,556,580CO2 Emissions, ton/year

233224236NOX Emissions, ton/year

1,1201,1861,244SO2 Emissions, ton/year

57.8158.160.00Biomass Burn Rate, kton/year

543.9575.6604.5Coal Burn Rate, kton/year

Torrefied Wood




Eastern Unit—Focus on Results

51.955.257.0Mercury Emissions, lbm/year

1,400,2271,482,0211,556,580


1,566,0801,565,1901,556,580CO2 Emissions, ton/year

233224236NOX Emissions, ton/year

1,1201,1861,244SO2 Emissions, ton/year

Torrefied Wood




Eastern Coal Unit—Fuel Related Economics

54.86757.02756.060Total Fuel-Related Cost

0.0930.1110.000Differential Station Service Cost

-0.0740.3380.000Differential Unavailability Cost

0.0001.0310.000Derate Power Cost

Replacement Power

1.2031.2801.325Mercury Emissions

-2.488-1.2480.000Renewable Credit

23.49123.47823.385CO2 Emissions

0.1170.1120.118NOX Emissions

0.1120.1190.125SO2 Emissions

Emissions

-0.0200.0070.000Differential Plant Maintenance

0.1140.1200.125Bottom Ash Disposal

0.5210.5490.571Fly Ash Disposal or Sales

-0.369-0.394-0.410Gypsum Sales

0.5680.6070.632FGD Scrubber Limestone

0.6190.5950.627SCR Reagent

Operations and Maintenance

0.0000.0000.000Gas Cost

30.98130.32229.563Coal/Biomass Cost

Fuel Cost

Annual Economic Results, $M

Torrefied WoodSawdust/

Sawmill ResidueCoalEconomic Parameter


Eastern Coal Unit—Focus on Economics


0.0930.1110.000Differential Station Service Cost


0.0001.0310.000Derate Power Cost

Replacement Power



23.49123.47823.385CO2 Emissions


0.1120.1190.125SO2 Emissions

Emissions


Fuel Cost


Torrefied Wood


Economic Parameter


Eastern Unit—for Comparison

53.81354.20156.060Total Fuel-Related Cost0.0680.0770.000Differential Station Service Cost

-0.213-0.2710.000Differential Unavailability Cost

Replacement Power1.1981.1631.325Mercury Emissions


Emissions31.02331.28329.563Coal/Biomass Cost

Fuel Cost


MiscanthusStraw

Raw Wood, 40% H2OCoal

Economic Parameter


PRB Unit—Technical Results

11.6312.8912.00Unit Opacity, %


0.340.340.35Boiler NOX, lbm/MBtu


NoneNoneNoneMost Limiting Item


LowLowLowFouling Potential

Med/HighMed/HighMedi/HighSlagging Potential

9.01.85.6Mill Capacity Margin, %

17.315.716.6Induced Draft Fan Margin, %

7.27.77.3Forced Draft Fan Margin, %



10,609.010,694.210,661.9NPHR, Btu/kWh

7.296.306.44Fly ash LOI, %

84.7784.1584.38Boiler Efficiency, %

240.07239.93240.00Net Power, MW

Full-Load Results

Torrefied WoodSawdust/

Sawmill ResidueCoal



PRB Unit—Deep Dive

85.3984.7885.00Equivalent Availability, %74.9974.9974.99Net Capacity Factor, %53.457.679.8Mercury Emissions, lbm/year

1,629,5751,732,1681,818,050


1,820,4501,828,3001,818,050CO2 Emissions, ton/year286290298NOX Emissions, ton/year

5,1855,5115,769SO2 Emissions, ton/year66.5367.230.00Biomass Burn Rate, kton/year896.7953.21,000.4Coal Burn Rate, kton/year

Torrefied Wood


Performance Parameter, Annual


PRB Economics


-0.0180.0080.000Differential Station Service Cost


Replacement Power



27.30727.42527.271CO2 Emissions


0.5190.5510.577SO2 Emissions

Emissions

-0.0330.0090.000Differential Plant Maintenance

0.0620.0660.068Bottom Ash Disposal

0.3530.3740.382Fly Ash Disposal or Sales

0.0000.0000.000Gypsum Sales

0.0000.0000.000FGD Scrubber Limestone

0.7590.7690.790SCR Reagent

Operations and Maintenance


Fuel Cost

Torrefied Wood


Economic Parameter, Annual Economic Results, $M


PRB Economics Deep Dive

52.13253.08353.249Total Fuel-Related Cost-0.0180.0080.000Differential Station Service Cost


Replacement Power1.2391.3361.852Mercury Emissions


27.30727.42527.271CO2 Emissions


0.5190.5510.577SO2 Emissions

Emissions24.95823.67922.160Coal/Biomass Cost

Fuel Cost

Torrefied Wood


Economic ParameterAnnual Economic Results, $M


Case Study 1: Key Take-Aways

• Under the conditions of the study (very favorable to biomass in general and particularly torrefaction), torrefied biomass was a good choice from an operating cost perspective– Total Fuel Related Cost is a reasonable surrogate for

bid price• The study DID NOT look at capital cost or levelized cost

of electricity (LCOE)• The lower emissions levels of NOx, SO2, and Hg

attributable to torrefied wood had mostly very marginal benefits– This is probably true for the entire US generating fleet


Study for EPRI RETG: Cofiring Analysis

• The basis:– 250 MW T-Fired unit, designed for high-S CAPP– Baseload unit w/good availability– SCR, Scrubber, cold side ESP

• Considered cofiring cases at 5%, 10%, 15% heat input with three different fuels:– Wood chips (45% moisture)– Dried biomass (30% moisture)– Torrefied biomass (6% moisture)

• Focus on performance—efficiency, capability, maintenance & availability

• Examined all major plant equipment systems


RETG Study Conclusions

• Focus on performance—efficiency, capability, maintenance & availability—little emphasis on cost

• Examined all major plant equipment systems in detail– Moisture matters– Lower ash content helps within the capabilities of the

model• Slight degradation in capacity and heat rate

– Small predicted increases in LOI, slagging


Overall Conclusions

• Vista offers an opportunity to provide an unbiased technical evaluation of different fuels for any boiler

• Understanding the technical issues allows accurate picture of fuel-related cost structure– Costs can be all-inclusive or not, per user need– Fuel related costs are a reasonable surrogate for bid

price• Vista can handle capital costs and can calculate LCOE,

but those functions were not used for these illustrations• Most utilities use a sophisticated approach when

evaluating fuels• Because of the low incremental value of emissions

reductions, “Value Pricing” of torrefied biomass is unlikely to be successful


Together…Shaping the Future of Electricity

Documents

14 Evaluating Supplemental Fuels using Vista …mydocs.epri.com/docs/publicmeetingmaterials/1104/73NXUF...All rights reserved. 6 Building On - Identifying Costs 0 50 100 150 200 250