IPM Model – Updates to Cost and Performance for APC Technologies

Wet FGD Cost Development Methodology

Final

March 2013

Project 12847-002

Systems Research and Applications Corporation

Prepared by

55 East Monroe Street • Chicago, IL 60603 USA • 312-269-2000
LEGAL NOTICE

This analysis ("Deliverable") was prepared by Sargent & Lundy, L.L.C. ("S&L"), expressly for the sole use 

of Systems Research and Applications Corporation ("Client") in accordance with the agreement between 

S&L and Client. This Deliverable was prepared using the degree of skill and care ordinarily exercised by 

engineers practicing under similar circumstances. Client acknowledges: (1) S&L prepared this Deliverable 

subject to the particular scope limitations, budgetary and time constraints, and business objectives of the 

Client; (2) information and data provided by others may not have been independently verified by S&L; and 

(3) the information and data contained in this Deliverable are time sensitive and changes in the data, 

applicable codes, standards, and acceptable engineering practices may invalidate the findings of this 

Deliverable. Any use or reliance upon this Deliverable by third parties shall be at their sole risk. 

This work was funded by the U.S. Environmental Protection Agency and reviewed by William A. Stevens, 

Senior Advisor – Power Technologies. 
IPM Model – Updates to Cost and Performance for 

APC Technologies

Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 1

Establishment of Cost Basis

The 2004 to 2006 industry cost estimates for wet FGD units from the "Analysis of MOG 

and Ladco's FGD and SCR Capacity and Cost Assumptions in the Evaluation of

Proposed EGU 1 and EGU 2 Emission Controls" prepared for Midwest Ozone Group

(MOG) were used by Sargent & Lundy LLC (S&L) to develop the wet FGD cost model. 

In addition, S&L included data from “Current Capital Cost and Cost-effectiveness of 

Power Plant Emissions Control Technologies” prepared by J. E. Cichanowicz for the 

Utility Air Regulatory Group (UARG) in 2010. The cost increases reported from 2007 to 

2008 by G. W. Sharp in “Update: What’s That Scrubber Going to Cost?” published in 

Power Magazine, March 2009 were also considered. The published data was 

significantly augmented by the S&L in-house database of recent wet FGD projects.

Cost data from the various sources showed similar trends versus generating capacity. 

Escalation based on the CEPI was deemed acceptable. All data sources were combined 

so as to provide a representative wet FGD cost basis.

The data was converted to 2012 dollars based on the Chemical Engineering Plant Index

(CEPI) data. Additional proprietary S&L in-house data from 2007 to 2012 were included 

to confirm the index validity. Finally, the cost estimation tool was benchmarked against 

recent wet FGD projects to confirm the applicability to the current market conditions. 

The least squares curve fit of the data was defined as a "typical" wet FGD retrofit for 

removal of 98% of the inlet sulfur. It should be noted that the lowest available SO2

emission guarantees, from the original equipment manufacturers of wet FGD systems, are 

0.04 lb/MMBtu. The typical wet FGD retrofit was based on:

Retrofit Difficulty =1 (Average retrofit difficulty);

Gross Heat Rate = 9500 Btu/kWh;

SO2 Rate = 3.0 lb/MMBtu;

Type of Coal = Bituminous;

Project Execution = Multiple lump sum contracts; and

Recommended SO2 emission floor = 98% removal efficiency or 0.06 

lb/MMBtu.

Units below 100 MW will typically not install a wet FGD system. Sulfur reductions for 

the small units would be accomplished by; treating smaller units at a single site with one 

wet FGD system, switching to a lower sulfur coal, repowering or conversion to natural 

gas firing, dry sorbent injection, and/or a reduction in operating hours. Capital costs of 

approximately $900/kW may be used for units below 100 MW under the premise that 

these will be combined.
IPM Model – Updates to Cost and Performance for 

APC Technologies

Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 2

Methodology

Inputs

Several input variables are required in order to predict future retrofit costs. The gross 

unit size in MW (equivalent acfm) and sulfur content of the fuel are the major variables

for the capital estimation. A retrofit factor that equates to difficulty in construction of the 

system must be defined. The costs herein could increase significantly for congested sites. 

The gross unit heat rate will factor into the amount of flue gas generated and ultimately

the size of the absorber, reagent preparation, waste handling, and balance of plant costs. 

The SO2 rate will have the greatest influence on the reagent handling and waste handling 

facilities. The type of fuel (Bituminous, PRB, or Lignite) will influence the flue gas 

quantities as a result of the different typical heating values.

The evaluation includes a user selected option for a wastewater treatment facility. The 

base capital cost includes minor physical and chemical wastewater treatment. However, 

in the future more extensive wastewater handling may be required. Although an option 

for wastewater treatment is provided, no logic has been developed to accommodate the 

additional wastewater treatment costs.

The cost methodology is based on a unit located within 500 feet of sea level. The actual 

elevation of the site should be considered separately and factored into the cost due to the 

effects on the flue gas volume. The base absorber island and balance of plant costs are 

directly impacted by the site elevation. These two base cost modules should be increased 

based on the ratio of the atmospheric pressure between sea level and the unit location. As 

an example, a unit located 1 mile above sea level would have an approximate 

atmospheric pressure of 12.2 psia. Therefore, the base absorber island and balance of 

plant costs should be increased by:

14.7 psia/12.2 psia = 1.2 multiplier to the base absorber island and balance of plant costs

Outputs

Total Project Costs (TPC)

First the installed costs are calculated for each required base module. The base module 

installed costs include:

All equipment;

Installation;

Buildings;

Foundations;

Electrical;
IPM Model – Updates to Cost and Performance for 

APC Technologies

Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 3

Minor physical and chemical wastewater treatment (WWT); and

Retrofit difficulty.

The base modules are:

BMR = Base absorber island cost

BMF = Base reagent preparation cost

BMW = Base waste handling cost

BMB = Base balance of plant costs including: ID or booster fans, new wet chimney, piping, 

ductwork and reinforcement, minor WWT, etc...

BMWW = Base wastewater treatment facility for future use.

BM = BMR + BMF + BMW + BMB + BMWW

The total base module installed cost (BM) is then increased by:

Engineering and construction management costs at 10% of the BM cost;

Labor adjustment for 6 x 10 hour shift premium, per diem, etc., at 10% of the 

BM cost; and

Contractor profit and fees at 10% of the BM cost.

A capital, engineering, and construction cost subtotal (CECC) is established as the sum of 

the BM and the additional engineering and construction fees.

Additional costs and financing expenditures for the project are computed based on the 

CECC. Financing and additional project costs include:

Owner's home office costs (owner's engineering, management, and 

procurement) at 5% of the CECC; and

Allowance for Funds Used During Construction (AFUDC) at 10% of the 

CECC and owner's costs. The AFUDC is based on a three-year engineering 

and construction cycle.

The total project cost is based on a multiple lump sum contract approach. Should a 

turnkey engineering procurement construction (EPC) contract be executed, the total 

project cost could be 10 to 15% higher than what is currently estimated.

Escalation is not included in the estimate. The total project cost (TPC) is the sum of the 

CECC and the additional costs and financing expenditures. 
IPM Model – Updates to Cost and Performance for 

APC Technologies

Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 4

Fixed O&M (FOM)

The fixed operating and maintenance (O&M) cost is a function of the additional 

operations staff (FOMO), maintenance labor and materials (FOMM), and administrative 

labor (FOMA) associated with the wet FGD installation. A future fixed O&M cost 

category is included to account for an extensive wastewater treatment facility. At this 

time, the wastewater treatment fixed O&M (FOMWW) is not estimated and is included at 

zero dollars. The FOM is the sum of the FOMO, FOMM, FOMA, and FOMWW.

The following factors and assumptions underlie calculations of the FOM:

All of the FOM costs were tabulated on a per kilowatt-year (kW yr) basis.

In general, 12 additional shift operators are required for a 500 MW or smaller 

installation. Units larger than 500 MW require a total of 16 additional shift 

operators. The FOMO was based on the number of additional operations staff 

required as a function of generating capacity.

The fixed maintenance materials and labor is a direct function of the process 

capital cost at 1.5% of the BM.

The administrative labor is a function of the FOMO and FOMM at 3% of 

(FOMO + 0.4FOMM).

Variable O&M (VOM)

Variable O&M is a function of:

Reagent use and unit costs;

Waste production and unit disposal costs;

Additional power required and unit power cost;

Makeup water required and unit water cost; and

Future variable O&M cost category is included to account for an extensive 

wastewater treatment facility.
IPM Model – Updates to Cost and Performance for 

APC Technologies

Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 5

The following factors and assumptions underlie calculations of the VOM:

All of the VOM costs were tabulated on a per megawatt-hour (MWh) basis.

The reagent usage is a function of gross unit size, SO2 feed rate, and removal 

efficiency. While the capital costs are based on a 98% sulfur removal design, 

the operating sulfur removal percentage can be adjusted to reflect actual 

variable operating costs.

A calcium-to-sulfur stoichiometric ratio of 1.03 was used as the basis for the 

reagent use rate. In addition, a limestone purity of 90% CaCO3 with the 

balance being inert material was defined to establish the total reagent feed 

rate.

The waste generation rate is directly proportional to the reagent usage and is 

estimated based on 10% moisture in the by-product.

The additional power required includes increased fan power to account for the 

added wet FGD pressure drop. This requirement is a function of gross unit 

size (actual gas flow rate) and sulfur rate.

The additional power is reported as a percent of the total unit gross 

production. In addition, a cost associated with the additional power 

requirements can be included in the total variable costs.

The makeup water rate is a function of gross unit size (actual gas flow rate) 

and sulfur feed rate.

A future variable O&M cost category is included to account for an extensive 

wastewater treatment facility. At this time, the wastewater treatment variable 

O&M (VOMWW) is not estimated and is included at zero dollars. 
IPM Model – Updates to Cost and Performance for 

APC Technologies

Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 6

Input options are provided for the user to adjust the variable O&M costs per unit. 

Average default values are included in the base estimate. The variable O&M costs per 

unit options are:

Limestone cost in $/ton;

Waste disposal costs in $/ton;

Auxiliary power cost in $/kWh;

Makeup water costs in $/1000 gallon; and

Operating labor rate (including all benefits) in $/hr.

The variables that contribute to the overall VOM are:

VOMR = Variable O&M costs for limestone reagent

VOMW = Variable O&M costs for waste disposal

VOMP = Variable O&M costs for additional auxiliary power

VOMM = Variable O&M costs for makeup water

VOMWW = Variable O&M costs for wastewater treatment

The total VOM is the sum of VOMR, VOMW, VOMP, VOMM, and VOMWW. Table 1

is a complete capital and O&M cost estimate worksheet.
IPM Model – Updates to Cost and Performance for APC Technologies Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 7

Table 1. Example Complete Cost Estimate for the Wet FGD System
IPM Model – Updates to Cost and Performance for APC Technologies Project No. 12847-002

March 2013

Wet FGD Cost Development Methodology

Page 8