A Mid-sized WWTP’s Journey to Energy IndependenceJou ey to e gy depe de ce

Sheboygan, WI Experience with CHP

Dale Doerr, SuperintendentSheboygan Regional Wastewater Treatment PlantSheboygan Regional Wastewater Treatment Plant

NBP Webcast

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September 22, 2010

Agendag• Sheboygan Regional WWTP• Why CHP• CHP Performance • Benefits of CHP• Lessons Learned• Lessons Learned• Optimizing Biogas Production• What’s Next• Questions

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Sheboygan Regional WWTP • Built 1982 • 18.4 MGD Permitted Flow• 11 0 MGD Average Flow11.0 MGD Average Flow• Serves 68,000 People

– City of Sheboygan– City of Sheboygan Falls– Village of Kohler– Town of Lima– Town of Sheboygan– Town of Sheboygan FallsTown of Sheboygan Falls– Town of Wilson

• 2009 – Operating Budget $ 3.99Mp g g $– Debt Service $ 355K– Capital Outlay $ 710K– Energy Costs $ 328K

33333 Lakeshore Drive

Sheboygan Regional WWTP• Preliminary/Primary Treatment

– Screening – Grit RemovalGrit Removal– Primary Clarifiers

• Two Treatment Trains– Biological Nutrient Removal– Aeration Basins

• Fine Bubble Membrane Diffusers• High Efficiency Turblex® Blower

– Final Clarifiers– Chlorine Disinfection– Dechlorination– Anaerobic Digestion

• Methane Gas Recovery CHP• Methane Gas Recovery, CHP– Gravity Belt Thickening– Bio-solids Storage 6 - MG– Bio-solids are Land Applied

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Wastewater Treatment Plant Staff

PlantSuperintendent

Staffed HoursMon – Fri :6:00 AM – 6:00 PMS t S 6 00 AM 2 00 PM

Clerk Industrial WasteChemist

Industry

Sat – Sun 6:00 AM – 2:00 PM

y

Operations (5)

MaintenanceSupervisorOperator III Operator III

Laboratory (1)

LaboratoryTechnician

Maintenance (7)

Operator IOperator III

ElectronicsTechnician Electrician

MaintenanceTechnician

MaintenanceTechnicianOperator I

5MaintenanceTechnician Janitor

Operator I

Why CHP?• Waste Heat Study in 2003

• Alliant Energy Power Plant Next DoorAlliant Energy Power Plant Next Door• 250,000 gpm of hot water discharged to Lake Michigan

• Use for excess biogasFlaring 50 000 ft3 of biogas per day• Flaring 50,000 ft3 of biogas per day

• Experiences with a Reciprocating Engine• Fuel CellsFuel Cells• Micro-Turbine Technology• Alliant Energy offers to pay for electrical generationAlliant Energy offers to pay for electrical generation

portion of Micro-turbine Installation

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Cogeneration Project• Startup February 15, 2006

Outside Temperature 20° F– Outside Temperature - 20° F• Installed

• 10 – 30 KW Capstone Micro-turbines• Gas Compression Gas Filtration System• 2 – Cain Heat Exchangers• Piping and Pumps to Utilize Heat Generated by

Micro-turbines• Monitoring and Control System

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Cogeneration Project

10 - 30 kW Capstone Micro-turbines

8

10 30 kW Capstone Micro turbines

Cogeneration Project

9Biogas Gas Conditioning (moisture removal, compression and carbon filters)

Cogeneration Project

10Electrical Switch Gear and Power Monitors

Cogeneration ProjectHeat Recovery - Cain Heat Exchangers

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Cogeneration Project

Hot Water Loop Recirculation Pumps

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Cogeneration Project

13January 16, 2008

Facility:

Part 1 - Summary of Prime Mover Electrical Output Part 2 - Description of CHP Prime Mover

Sheboygan Regional Wastewater Treatment Plant

Digester-Gas-Fueled Combined Heat and Power Performance Data Sheet

Respondent: Dale L. Doerry p p

2/15/2006241242

95%97%

Mechanical Capacity (hp):Installation Date:

Plant Flow (MGD):

Digester Gas Capacity (scfm):

97%97%

100%

11.775

Model Number:Electrical Capacity (kW):

Manufacturer:CHP Prime Mover:

(% of Full Load) Capstone Micro-turbine Corporation10 - 30 kW Micro-turbines Date:

p

Electrical Output(kW)

2/5/2010

490,000

Net Electrical Output

239241250

300C-30

Part 3 - Prime Mover - Photograph Part 5 - Prime Mover and Appurtenant Equipment - Process Flow Diagram

24195%

Uptime 87.4%Return to InstructionsReturn to Instructions

Part 4 - Prime Mover - System Description

10 - 30 kW Capstone Micro-turbines with a custom gas conditioning - Gas compression skid built by Unison Solutions, 2 - heat exchangers for heatrecovery built by Cain Industries and electrical switchgear with power grid lockout

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recovery built by Cain Industries, and electrical switchgear with power grid lockout.

Part 6 - Operation and Limitations

Change out the inlet air filters on the micro-turbines and replace the disposable carbon media (for siloxane removal) every 10 weeks Electrical energy (kW) drops when ambient temperature gets above 60 degrees. During cold weather the micro-turbine electrical output is 30 kW each unit, As the ambient air temperature increases to 75 - 80 degrees the micro-turbine kW output drops 22 kW each unit.

Facility:

Date: 2/5/2010

Sheboygan Regional Wastewater Treatment Plant

Respondant: Dale L. DoerrReturn to InstructionsReturn to Instructions

Part 7 - Prime Mover - Fuel Data

550

Digester Gas HHV (Btu/ft3) 650

Digester Gas LHV (Btu/ft3)

300Prime Mover Rated Output (kW)

Part 7 Prime Mover Fuel Data

4,251,000 1,246

Based on Lower Heating Value (LHV) Based on Higher Heating Value (HHV)Fuel Energy (Btuh) Fuel Energy (kW)Fuel Energy (Btuh) Fuel Energy (kW)

4,329,000 1,2684,407,000

2009 - 75 percentile 10990.0% 3,597,000

100.0%Digester Gas Flow (scfm)

3,663,0003,729,0001133,795,000115

1,073111Load Description Percent of Full Load

2007 - 75 Percentile 95.3%Full Rated Capacity:

2008 - 75 Percentile 89.0%1,0931,1121,054

1,2914,485,000 1,314

Part 8 - Prime Mover - Electrical Efficiency

Ancillary Loads (kW) Net Production (kW)

1,160

25049 23750 217

50

4,680,000 1,371

286267

3,960,000

24%

94.7%

Full Rated Capacity: 100.0%26%

Gross Electrical

2008 75 Percentile 89 0%2007 - 75 Percentile 95.3%

300

23-Feb-10 120

Load Description Percent of Full Load28% 23%

20%22%

Net Electrical EfficiencyElectrical Output (kW)

Part 9 - Prime Mover - Thermal Efficiency

22150 217

284270 26%267

2009 - 75 percentile 90.0%24%

24%2008 - 75 Percentile 89.0%

21%21%20%

43 24149

Load Description27%1,000,000

Thermal EfficiencyThermal Recovery (Btuh)Jacket Water (Btuh)

23-Feb-10 94.7%

Full Rated Capacity: 100.0%Percent of Full Load

1,000,000

Part 10 - Prime Mover - Total Efficiency

22%23%22%24%27%1,000,000

852,711 852,711897,928

Full Rated Capacity: 100.0%

2009 - 75 percentile 90.0%94.7%23-Feb-10

1,000,000897,9282007 - 75 Percentile 95.3%

2008 - 75 Percentile 89.0%

876,784835,539

876,784835,539

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Total Efficiency

43%44%42%46%

23-Feb-10 94.7%2009 - 75 percentile 90.0%

Load Description Percent of Full Load

2008 - 75 Percentile 89.0%

100.0%2007 - 75 Percentile 95.3%Full Rated Capacity: 51%

2006 2007 2008 2009 AverageMaintenance Costs

Net kWH 1,590,800 1,768,600 1,666,200 1,620,500 1,647,380

Parts & Materials 15,073.68$ 35,176.00$ 38,072.00$ 40,027.00$ 31,333.49$ Siloxane Media 10 113 24$ 13 680 00$ 15 898 00$ 10 778 00$ 12 335 85$Siloxane Media 10,113.24$ 13,680.00$ 15,898.00$ 10,778.00$ 12,335.85$ Siloxane Media Disposal 3,390.84$ 7,578.00$ 7,912.00$ 6,351.00$ 6,259.76$

Subtotal Parts & Materials 28,577.76$ 56,434.00$ 61,882.00$ 57,156.00$ 49,929.09$ Cost/ kWH 0.0180$ 0.0319$ 0.0371$ 0.0353$ 0.0303$Cost/ 0.0180$ 0.0319$ 0.0371$ 0.0353$ 0.0303$

Labor 8,942.50$ 7,665.00$ 9,231.00$ 7,801.00$ 8,099.96$ Travel 16,468.47$ 15,073.00$ 19,690.00$ 13,177.00$ 15,545.03$

Subtotal Labor & Travel 25,410.97$ 22,738.00$ 28,921.00$ 20,978.00$ 23,644.98$ Cost/ kWH 0.0160$ 0.0129$ 0.0174$ 0.0129$ 0.0144$

Total O&M 53 988 73$ 79 172 00$ 90 803 00$ 78 134 00$ 73 574 07$Total O&M 53,988.73$ 79,172.00$ 90,803.00$ 78,134.00$ 73,574.07$ Cost/ kWH 0.0339$ 0.0448$ 0.0545$ 0.0482$ 0.0447$

Capital Expense to Install New Chiller Unit 58,000.00$

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p p ,$

1 Replacement Engine 3 Replacement Engines 1 Replacement EngineRepair Chiller Repair Chiller Repair Chiller Repair Chiller

Maintenance• Alliant Energy is responsible for all Maintenance

– Preventive• Change out MT Inlet Air Filters

– Every 8 Weeks• Replace Carbon Media for Siloxane RemovalReplace Carbon Media for Siloxane Removal

– Every 10 - 12 Weeks• Change Gas Compressor Oil

Annually– Annually

– Corrective• Engines• Control Modules (internal PLC)• SPV Valve (Gas Flow Control Valve)• Igniters

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Igniters

Cogeneration Project Costs• Estimated Project Cost $1,200,000• City's Cost $205 000• City s Cost $205,000• Alliant Energy’s Cost $1,000,000 (estimated)

• Focus On Energy Grants– Electrical, Approved for but Not Eligible for pp g

($45,000)– Heat Recovery, $20,000

• The City recovered its cost in just over 2-years

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y

2006 2007 2008 2009Benefits from CHP 2006 - 2009

2006 2007 2008 2009

Renewable Energy Credits (RECs) 924 2,076 1,619 1,571$$ Per REC $3.15 $3.15 $3.15 $0.95Revenue from RECs $2,911 $6,539 $5,100 $1,492

Revenue from Alliant Energy $23,372 $27,118 $25,730 $27,230

Therms Reco ered 60 449 66 369 65 602 60 247Therms Recovered 60,449 66,369 65,602 60,247Cost PerTherm $0.9039 $0.8347 $0.8666 $0.7352Natural Gas Savings $54,640 $55,398 $56,851 $44,294g

Wisconsin Focus On Energy Grant $20,000

19Total Revenue $100,922 $89,056 $87,681 $73,016

2006 2007 2008 2009Value of Energy Produced 2006 - 2009

2006 2007 2008 2009

Days System Down (All Day) 45 23 3 18y y ( y)

Annaul Therms 60,449 66,369 65,602 60,247A erage Dail BTUs 18 890 313 19 406 140 18 072 176 17 362 248Average Daily BTUs 18,890,313 19,406,140 18,072,176 17,362,248Value of Heat Produced $54,640 $55,398 $56,851 $44,294Cost Per Therm $0.9039 $0.8347 $0.8666 $0.7352$0.9039 $0.8347 $0.8666 $0.7352

Annual kWH 1,590,800 1,768,600 1,666,200 1,620,500A D il kWH 9 1 1 1 603 6 0Average Daily kWH 4,971 5,171 4,603 4,670Value of Electricity Prouced $98,684 $113,908 $112,169 $109,510Cost Per kWH $0 0620 $0 0644 $0 0673 $0 0676

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Cost Per kWH $0.0620 $0.0644 $0.0673 $0.0676

Total Value of Energy Produced $153,324 $169,306 $169,020 $153,804

Lessons LearnedLessons Learned

• Operation during cold weather– Heat Tape Gas Supply Lines

• Placement of Chiller Unit• Provide adequate space for gas

conditioning equipmentconditioning equipment

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High Strength Industrial Wastes• High Soluble Organic Wastes

– High Biochemical Oxygen Demand (BOD) > 25,000 mg/l– Low Total Suspended Solids (TSS) < 20,000 mg/l

E– Easy to pump– Provides increase in Methane Gas Production within minutes

• Currently using the following Food Processing WasteAdel Whey– Adel Whey

• Mother Liquor, ~120,000 mg/L BOD• Permeate, ~100,000 BOD• Permeate Rinse Water ~60 000 mg/L BODPermeate Rinse Water, 60,000 mg/L BOD

– Jeneil Biotech• Flavorings for Dairy Products, ~25,000 mg/L BOD

– Lake to Lake Cheese• Cheese Processing Brine 35,000 mg/L BOD

• Evaluating the following Food Processing Waste– Saputo Foods

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• Permeate, ~400,000 BOD, 50% Total Solids, 80% Volatile Solids

Impact of Soluble BOD on Methane Gas ProductionDecember 2006

600 000 20 000

500,000

600,000

16 000

20,000

400,000

c Fe

et)

12 000

16,000

305,218 Average300,000

hane

Gas

(Cub

ic

8,000

12,000

BO

D (P

ound

s)

200,000Met

h

4,000

8,000

0

100,000

0

,

23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Dec-06, With High Strength Waste Adell Whey (40,000 BOD) Schrieber Foods (33,000 BOD)

Total Methane Gas Produced (Used)December 2005 compared to March 2009

600 000

500,000

600,000

491,157 Average

400,000

Feet

)

300,000

ane

Gas

(Cub

ic

233,065 Average200,000M

etha

0

100,000

24

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Dec-05, Without High Strength Waste March 2009, with High Strength Waste

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Summary• Using methane gas to produce energy on-site, has

reduced our dependency on outside energy sources. (electric and natural gas). ( g )

• Using methane gas to fuel the micro-turbines has reduced our green house gas emissions (Methane and Carbon Dioxide)

• Metering-in “High Strength” organic wastes into the anaerobic digesters has increased methane gas production by more than 100 percent.

• The Capstone® Micro-turbines produced 6,646 MWh of Electrical Energy and 252,667 Therms of heat since startup in February 2006.

• The 6,646 MWh of electricity reduced our carbon dioxide emissions by more than 6,000,000 pounds, the equivalent of planting 16,000 trees.

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What’s Planned for the Future

• 2010 -2011Digester Mixing Improvements– Digester Mixing Improvements

– More Capstone Micro-turbines (400 kW) • 2012 Class “A” Bio solids Project• 2012 Class A Bio-solids Project

– Low temperature sludge dryerUse excess heat for sludge stabilization– Use excess heat for sludge stabilization

– Produce a reusable soil amendment • 2013 & 2014 More Energy Projects• 2013 & 2014 More Energy Projects

– Solar Electric Energy Project• 225 000 ft2 of flat roof area

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• 225,000 ft of flat roof area• 2 megawatts of energy

Web Links to ArticlesWeb Links to Articles

• http://www werf org/AM/Template cfm?Section=Hom• http://www.werf.org/AM/Template.cfm?Section=Home&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=10245

• http://www.jgpress.com/archives/_free/001831.html• http://www.nyserda.org/programs/Environment/07-

08%20Final%20Report pdf08%20Final%20Report.pdf• http://www.biosolids.org/news_weekly.asp?id=1928• http://www distributedenergy com/march-april-http://www.distributedenergy.com/march april

2009/sludge-is-power.aspx• http://www.tpomag.com/editorial/view/3110/Savings-

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Everywhere

Contact Info:Contact Info:Dale L. DoerrCit of Shebo gan WWTPCity of Sheboygan WWTP920-459-3464 TELdale.doerr@sheboyganwwtp.com

Website: www.sheboyganwwtp.com29