Appendix O

 Cargill RFP Analysis

 
A w Ca~g~ll Sweeteners 

North America 

August 2,2007 

Timothy S. Owen, Chief 

Energy Branch 

Air Division 

Alabama Department of Environmental Management 

1400 Coliseum Blvd. 

Montgomery, AL 361 10-2059 

Dear Mr. Owen: 

In response to your request on July 3, Cargill is providing herein our estimates of the costs of 

SO2 emission controls for the Keeler Stoker Boiler (Unit S-407) at our Decatur plant. In addition 

to providing our cost estimates, this letter also presents information we have gathered that 

underlies our concern about whether applying controls to our boiler would be effective in 

reducing visibility impacts. 

COST ESTIMATES 

For a stoker type boiler such as Unit S-407, the following control technology options are 

generally considered for the reduction of SO2 emissions: 

Lower sulfur coals 

Wet scrubbers 

Dry scrubbers 

We are not providing cost estimates for the option of burning lower sulfur coal, because in the 

time we had available to evaluate this alternative, we were not able to determine whether this is 

both an available and technically feasible choice for Unit S-407. We are particularly concerned 

about the following issues: 

The sulfur content of the coal we have been burning since 1999 has averaged 

approximately 1.2 to 1.3 IbIMMBtu. Accordingly, we would most likely need to obtain 

coal from the western USA, such as the Powder River Basin (PRB), to achieve any 

reductions in SO2 emissions via lower sulfur coal. The information we have available to 

us indicates that lower sulfur coal is largely under contract at this time and may not be 

available for new users, and that this is unlikely to change in the foreseeable future. We 

are also aware that these coal types are typically not available to industrial plants except 

in cases where a relatively local coal-fired power plant "host" has a committed supply. 

We do not know at this time whether such a host is available to us. 

1030 State Docks Road Te1256-355-88 15 

Decatur; AL 3560 1 - 7538 Fax 256-351 -8012 
Our boiler was not designed to burn a low sulfur western coal. Since these coal types 

typically have a higher dust content than the coal we are currently burning, significant 

boiler modifications could potentially be required in order for us to be able to burn it. 

Even so, burning coal with a higher dust content could increase the risk of spontaneous 

combustion in coal bunkers, silos, and hoppers. Slag buildup and removal could also be 

a more appreciable problem. Our operators would need to learn how to limit damage 

from slag buildup on boiler tubes, and how to capture and control the additional dust cost 

effectively without compromising safety. For these reasons, PRB coal is typically not 

burned in stoker boilers such as Unit S-407. 

Lower sulfur western coals have lower heat values than the coal we are currently 

burning. Thus even if such coal was available to us, and was technically feasible for us 

to burn it, the boiler will generate less heat burning it than it does currently, and so to 

generate the same amount of heat as we do currently, we would have to burn more coal. 

We are providing estimates of the costs associated with employing either a wet or dry SO2 

scrubber for Unit S-407. Our estimates were derived using information we obtained from the 

following USEPA documents, supplementing this with information we have from equipment 

vendors: 

Air Pollution Control Technology Fact Sheet - Flue Gas Desulfurization (FGD) - Wet, 

Spray Dry, and Dry Scrubbers, available at 

~://www.epa.aovlttn/catc/dirl Iffdg. pdf 

@ Air Pollution Control Technology Fact Sheet - Packed-BedIPacked-Tower Wet Scrubber, 

available at http://www.epa.aov/ttn/catc/dirl/fpack.pdf 

These documents present the most up-to-date guidance that USEPA has published regarding 

cost levels for wet and dry scrubbers. Each provides a range of factors for estimating capital 

and operating costs. Our resulting cost estimate ranges, derived using these factors, updated 

to current dollar values, and based on assuming that a minimum SO2 emissions reduction 

efficiency of 90% can be achieved, are as follows: 

Total capital costs ............ range from $1.3 million to $36 million 

Total operational costs .... range from $192,000 to $1.9 millionlyear 

Cost-effectiveness.. . . . . . . . . . ranges from $1,00O/ton to $7,60O/ton 

We are concerned that our estimates of cost-effectiveness, measured in dollars per ton of 

emissions reduction, may be misleading for the purpose intended here, i.e., determining the 

effectiveness of a dollar expended in reducing impacts on visibility in the Sipsey Wilderness 

Area. As discussed below, our concern is based on our fundamental question as to whether 

Unit S-407 impacts visibility in Sipsey at all, and if so, how much. 
EFFECTIVENESS IN REDUCING VISIBILITY IMPACTS 

Figure 1 shows the location of the Cargill facility in Decatur, Alabama relative to Sipsey. It is 

evident that the facility is only about 50 km from Sipsey, but requires a northeast wind to 

transport the emissions from Unit S-407 to Sipsey. A 50-km transport distance is at the lower 

limit of consideration of regional haze due to SO2 transformation to sulfates because the travel 

time is rather minimal for much conversion to take place. On the other hand, this distance is too 

large for a coherent plume to be visible. 

Figure 2 shows a wind rose derived from 5 years of data from the nearest airport, Huntsville, 

Alabama. The wind rose indicates that of all possible directions, the wind has the lowest 

probability of blowing from the northeast (only about 3% of the time). Since the Regional Haze 

Rule reasonable further progress tracks the improvement in visibility for the 20% worst days, it 

is evident that even if the Cargill facility were contributing to these worst 20% days, it could only 

contribute to a small fraction of these at worst, and very well may not contribute to any of them 

at all due to the infrequency of northeast winds. Based upon this review of wind direction 

probabilities, we have serious doubts that any emission controls for Unit S-407 will change the 

reasonable further progress analysis outcome for Sipsey. 

Before any such emission controls are required, Cargill respectfully requests that ADEM needs 

to conclusively demonstrate that such controls would have a demonstrated effect on the 

reasonable further progress outcome for Sipsey. If needed, Cargill would be willing to retain a 

firm to conduct a refined modeling analysis for the subject boiler to determine if indeed the 

application of control would have a meaningful effect on regional haze in Sipsey. 

CONCLUSIONS 

We appreciate the Department's consideration of the information contained herein. As stated 

above, we would welcome the opportunity to work closely with the Department to assist you in 

developing a strategy to meet the National Progress Goals in the most cost-effective manner 

possible. Please direct any questions to me at (256) 351-4228 or email at 

heron@cargill.com 

Jaryes Heron 

EHS Manager 

Cargill, Inc. 

Decatur, AL 

DHL Waybill # 73225847240 
Figure 1 Location of the Cargill Decatur, AL facility with respect to Sipsey 
Figure 2 Five-year windrose for Huntsville, Alabama 

WIND #O@E PLOT: DISPLAY: 

Wind Rare for HuntsvlllelMadlson County Jet, AL Wind Speed 

8urfaae Wind Data Dire~tion (blowing from) - 

WIND 8PEEB 

(tH/8) 

2= 11.1 

8.8- 11.11 

1.9 - b.B 

m - 3.6 - 8.7 

1984 1985 1986 1987 1988 Carglll Jan 1 - Dec 31 

0o:Oo - 23:OO MODELER: 

A. Kieldsing 

CALM W INDS: TOTAL COUNT: ENSR / AI(:( 

7.84% 43848 hrs. 

AVO. WIND SPEED: DATE: PRQJEOT NO.: 

3.72 mls 7/25/2007 01 256-364-OlOQ 

RPLOt VIw - Lak~ Lnviranmentcrl Software 
," Catg~ll Sweeteners 

North America 

August 28,2007 

Timothy S. Owen, Chief 

Energy Branch 

Air Division 

Alabama Department of Environmental Management 

1400 Coliseum Blvd. 

Montgomery, AL 361 10-2059 

Dear Mr. Owen: 

We are responding to Mr. Dewayne Gaines' e-mail of August 21, 2007 regarding 

ADEM's request to narrow the SO2 cost effective range reported in my letter to you 

dated August 2, 2007. In responding we note the following: The Keeler Stoker Boiler 

(Unit S-407) at our Decatur plant is part of a Consent Decree that was lodged on 

September I, 2005 and entered by the Court on March 3, 2006. This Consent Decree 

was signed by Cargill, the U.S. EPA and other stakeholders, including the State of 

Alabama. Paragraph 15 of the Consent Decree requires Cargill to submit permit 

applications to the applicable permitting authority within three years from entry (March 2, 

2009) of the Consent Decree that will contain annual SO2 emission limits for the facilities 

and boilers listed in Appendix B of the Consent Decree that, in aggregate, limit total 

annual SO2 emissions to less than 15,355 tons per year based on a 12-month rolling 

sum. Unit S-407 is part of the Consent Decree and its SO2 emissions will be part of the 

cap. 

To meet the cap Cargill is authorized under the Consent Decree to make changes to the 

listed boilers that maintain the heat input capacity of the coal boiler (including changes to 

coal boiler fuel receiving and handling systems and ash handling systems) that do not 

result in an increase in any single pollutant's emissions above current boiler allowable 

emission rates or an increase in the heat input to the boiler and result in an overall 

decrease in emissions. As a result, Cargill will be evaluating numerous SO2 control 

options for Unit S-407 and per the Consent Decree will submit a permit application no 

later than March 2, 2009. Therefore, Cargill must retain the flexibility afforded by the 

Consent Decree to make SO2 changes if any at Unit S-407 to stay within the cap and not 

be bound by BART reasonable further progress. This is especially true in light of our 

August 2, 2007 response in which we stated that because of the source-receptor 

10.30 State Docks Road 

Decatu/; AL 3560 1 - 7538 

Tel256-355-8815 

Fax 256-35 1 -80 12 
relationship between Unit S-407 and the Sipsey Wilderness Area and the prevailing 

winds, SO2 reductions are not likely to have any real affect on regional Haze in Sipsey. 

Notwithstanding the above, Cargill is responding to ADEM's request to narrow the cost 

effective range by reporting on one SO2 control option - a wet scrubber starting with two 

different baseline SO2 emissions that are currently being considered under the Consent 

Decree. For this wet scrubber Cargill estimated that the total installed capital costs 

could range from $5MM to $10MM and total annual operating costs could range from 

$500,000 to $1.5MM. Therefore, in evaluating cost effectiveness for this response 

Cargill selected the mid-point of each of these ranges, i.e., $7.5MM total capital cost and 

$1MM total annual operating costs for the new wet scrubber. Cost effectiveness 

calculations using U.S. EPA procedure and these mid-points costs are reported below. 

Option 1 

This option assumes that Cargill will not reduce any additional SO2 emissions under the 

Consent Decree. The typical SO2 content of the coal currently burned in Unit S-407 is 

1.3 IbIMMBtu. The typical annual heat input to Unit S-407 is 1 .2x106 MMBtuIyr. This 

equates to a baseline mass emission of 780 TPY of SO2. We assumed 90% SO2 control 

from the wet scrubber and the mid-point capital and operating costs above. On this 

basis, the SO2 cost per ton controlled was calculated to be $2,946. 

This option assumes that Cargill will reduce SO2 emissions under the Consent Decree 

by 50% from its current levels. This equates to a baseline mass emission of 780 (see 

paragraph above) X 0.5 or 390 TPY of SO2. We assumed 90% SO2 control from the wet 

scrubber and the mid-point capital and operating costs above. On this basis, the SO2 

cost per ton controlled was calculated to be $5,891. 

CONCLUSIONS 

As part of the Consent Decree Cargill is evaluating numerous options for SO2 control on 

Unit S-407. We have presented cost effectiveness data for two options currently being 

considered. The SO2 cost effectiveness for Option 2 was calculated to be $5,89l/ton. 

Cargill concludes that this cost is higher than what would typically be considered cost 

effective for SO2 BART control. Even the cost effectiveness for Option 1 at over 

$2,90OIton is too high to be considered cost effective considering that SO2 reductions 

from Unit S-407 are likely to have little to no impact on regional haze at Sipsey for the 

reasons described above and in our letter dated August 2, 2007. 
We appreciate the Department's consideration of the information contained herein. We 

understand from previous correspondence that ADEM will not proceed with any BART 

reasonable further progress commitments for Unit 5-407 without further discussion with 

Cargill. Please direct any questions or meeting requests to me at (256) 351-4228 or 

email at hs. h.eecargill.com. 

Cargill, Inc. 

Decatur, AL 

cc: JJZmudzinski 

S. Peters 

V. Manetta 

ENSR 

Central File 
A Carg~li Sweeteners 

North America 

October 15, 2007 

Dewayne Gaines 

Energy Branch 

Air Division 

Alabama Department of Environmental Management 

1400 Coliseum Blvd. 

Montgomery, AL 361 10-2059 

DHL Waybill # 73225851 042 

Dear Mr. Gaines: 

The following information is in response to your email request October 2 concerning basis for 

calculations under option 1. A consultant utilizing a spreadsheet based on U.S. EPA BACT cost 

estimating procedures conducted the calculations. Due to time limitations the annual operating 

cost and the initial costs are estimates based on previous projects within our industry. The 

uncontrolled SO2 tonnage was calculated using our estimated annual MMBTU and 1.3 # SO2 

per MMBTU. 

If you need additional information please give me a call at (256) 351-4228 or email at 

james heron@.?cargill.com 

~a&sJheron 

EHS Manager 

Cargill, Inc. 

Decatur, AL 

1030 State Docks Road Tel256-355-8815 

Decatu~; AL 3560 1 - 7538 Fax 256-351 -8012