Three Business Models for Organic Waste to Energy Wednesday, March 6th :00am-11:30am PST/1:00pm-3:30pm EST

Transcription

1 Three Business Models for Organic Waste to Energy Wednesday, March 6th :00am-11:30am PST/1:00pm-3:30pm EST Speakers: John Welch: Recycling Manager of Dane County, WI George Dreckmann: Recycling Coordinator of Madison, WI Dale Doerr: Superintendent of the Wastewater Treatment Department of Sheboygan, WI

2 Dane County Community Manure Digester John Welch, Solid Waste Manager March 6, 2013

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4 Digester Diagram

5 History of Dane County Digester Manure runoff fish kill Manure Management Task Force Community Manure Management Feasibility Study Facility Planning Phase August Construction Start 2011 April Fully Operational

6 Dane County s Three Objectives Agricultural Viability & Sustainability Viable Alternatives Water Quality Protection Economic Feasibility

7 Overview of the Waunakee Project Located in the Town of Vienna Serves three primary farms ~2500 cows Manure piped to facility 10-15% food substrate added Complete mix mesophilic digestion, followed by solids separation with a centrifuge

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12 Project Benefits Meets Dane County s 3 objectives 60% - 70% P removal 2 MW production - $1.5M green electricity GHG emissions reduction 29,000 Tons/yr Allows farms to better manage nutrients Reduced P Less trucking and smaller land base Longer spreading window

13 Project Financing $12 million construction cost $3.3 M Dane County grant received from State of Wisconsin residual ownership $8.7 M private capital Clear Horizons $2.7 million Federal investment tax credit $6.0 million Clear Horizons debt

14 Revenue Sources Electricity $0.092 per kwh blended rate Fiber / Nutrients Bedding for farms Wholesale for compost, soil amendment, etc Tipping Fees for Substrates

15 Other/Future Revenue Sources Phosporous trading Heat industrial, greenhouse, etc BioCNG Competing with $4.00/gal diesel vs $0.05/kWh Nutrient Concentration System Precipitated nutrients Discharge water (value to farmers) Regulations feedstocks, renewable energy, etc

16 Nutrient Concentration System Clean water technology 100% phosphorus removal 65-70% water reduction Less hauling for farmers Added by-product value

17 County s Role - Project Development Multiple Players Farmers, Substrate Providers, Financers, Engineers, Technology Vendors, Utility Companies, Neighbors, Regulators (DNR, EPA, Town, County, State), Politicians (County Board, County Exectutive, Senators, Governor), Lawyers, Reporters, Environmentalists Project Cost / Financing Public Perception Utility Agreements / Interconnect Fees

18 County s Role - Project Development Permits DNR Right-of-Way Building Schedule Multiple Sites Unproven Technology?

19 Things to Consider for Biogas Projects Buyback rates ($0.02-$0.11/kWh) Revenue from byproducts Environmental impacts (Phosphorous, GHG, etc) Renewable or environmental credits Permitting and interconnection costs & schedule Feedstocks Gas potential, seasonality, long-term avaialability, pre-processing needs, distance Co-location options heat, electricity, CO2, BioCNG Site specific features

20 How to Encourage Future Projects Financial Electric Buyback Rate Investment Tax Credit GHG credits, Phosporous trading, etc Standardization Contracts Utility Requirements Permits and regulations Public Awareness

21 Thank You! John Welch epa.gov/agstar

22 SHEBOYGAN (WI) WWTP S JOURNEY TO SUSTAINABILITY THROUGH CO-DIGESTION Digester Cover Rehab Project Dale L. Doerr MBA Sheboygan Regional WWTP Three Business Models for Organic Waste to Energy Webinar - March 6, 2013

23 AGENDA Sheboygan Regional WWTP What is Co-digestion High Strength Wastes (HSW) Handling HSW Substrates Challenges and Benefits of Co-digestion Summary Questions 23

24 WHERE IS SHEBOYGAN, WI.? Green Bay Sheboygan Brat Capital of the World Madison Milwaukee 24

25 SHEBOYGAN REGIONAL WWTP Built MGD Permitted Flow 11.0 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 Falls Town of Wilson 2012 Operating Budget $4,453M Debt Service $ 602K Capital Outlay $ 600K Energy Costs $ 197K Tipping Fee Revenues $ 776K 25

26 LIQUID TRAIN Preliminary Treatment Screening Grit Removal Primary Clarifiers Two Treatment Trains BNR Activated Sludge Fine Bubble Diffused Air High Efficiency Blowers Secondary Clarifiers Chlorination De-chlorination

27 SOLIDS TRAIN Anaerobic Digestion Co-Digestion of HSW and Co-settled Primary- Waste Activated Sludge Methane Gas Recovery for Building Heat and Micro-turbine Co- Generation Facility Gravity Belt Thickening Liquid Biosolids Storage Liquid Biosolids are Land Applied Future Biosolids Drying Biosolids Drying (Future) Huber Belt Dryer

28 WHAT IS VALUE OF BIOGAS? 100 ft 3 of Biogas contains about 19.8 KWh of calorific energy at 66% methane, this is equivalent to: 0.66 ft 3 of Natural Gas 7.50 kwh of electrical energy approx. (if burned in a CHP) 8.25 kwh equivalent of useable heat energy 0.54 gallons of Gasoline 0.49 gallons of Diesel Fuel Is GHG Neutral Energy 28

29 WHAT IS CO-DIGESTION? CODIGESTION refers to the digestion of a combination of select biodegradable feed-stocks with a base substrate (primary sludge) in an anaerobic digestion system. is a process whereby energy-rich organic waste materials (e.g. food processing wastes, Fats, Oils, and Grease (FOG) and/or food scraps) are added to anaerobic digesters that have excess digestion capacity. HSW samples from MSG Mother liquor Permeate Rinse Water Beaker of blended material before injection into primary sludge line 29

30 WHAT IS THE INTENT OF CO-DIGESTION? The Intent of Co-Digestion is to maximize the production of biogas by adding readily biodegradable substrates that produce much more biogas per unit of mass than municipal sludge. Anaerobic digestion of readily biodegradable substrates provides approximately three to four times more methane production per volume of digester capacity than does municipal wastewater solids Digester Rehab

31 HIGH STRENGTH WASTES High Soluble Organic Wastes High Biochemical Oxygen Demand (BOD) > 25,000 mg/l Low Total Suspended Solids (TSS) < 10,000 mg/l Can have high dissolved solids, up to 50 percent TDS (mostly sugars) Must be easy to handle, pump, etc Usually see an increase in Methane Gas Production within 90 minutes Handling HSWs Has a low ph, usually 5.0 ph or less Delivery temperature may approach 120 F Stay away from wastes high in chlorides > 4,000 mg/l Can be corrosive Use corrosion resistant materials; i.e. stainless steel pumps, and SS, glass lined, or CPVC pipe Use 6 diameter or larger pipe 31

32 WHY CO-DIGESTION? Industry closings freed up capacity at the WWTP Industries outside of the service area were looking for disposal sites for their wastes We wanted to use the available WWTP capacity to increase revenues to reduce the amount of purchased energy Electricity & Natural Gas 32

33 HOW WE GOT STARTED We started by accepting a single waste from a company manufacturing flavorings for dairy products back in 2004 One load weekly was added directly to digesters which resulted in a short term increase in gas production We completed heating system upgrades in 2005 that tied the digester boiler heating loop to the building heating loop which increased the demand for biogas during the winter The startup of a 300 kw cogeneration facility in 2006 further increased the demand for biogas year round In 2006 we converted an empty digester tank into a HSW Holding/Blending tank and began metering HSW into primary sludge feed to digesters We continue to work with HSW generators and haulers to maintain a adequate stream of wastes suitable for co-digestion 33

34 HIGH STRENGTH WASTES Food Processing Wastes Whey Processing Mother Liquor, ~120,000 BOD Permeate, ~100,000 BOD Other Whey Processing Wastes, Ditch & DAF ~60,000 BOD Food Processing Flavorings for Dairy Products, ~25,000 BOD Cheese processing Wastes ~ 40,000 BOD Soda Processing Waste ~ 35,000 BOD Off Spec Beverage ~ 80,000 BOD Ethanol Production Waste Thin Stillage ~ 170,000 BOD Corn Syrup ~ 200,000 BOD Fats, Oil & Grease 34

35 HIGH STRENGTH WASTE STORAGE HSW Receiving & Storage 35

36 UNLOADING HSW Ideally you will need Days Storage Capacity For Sheboygan that is 250, ,000 gallons 36

37 HIGH STRENGTH WASTE FEED Vogelsang SS rotary lobe pump injects HSW into the primary sludge feed line before the anaerobic digesters Wet End is all SS after original (Standard) unit required a total rebuild after less than one year of operation It was determined that a brine waste with high chlorides (>57,000 ppm) caused corrosion that ate through the cast iron pump housing 37

38 BLENDING & FEEDING SUBSTRATES In-line Strainer HSW Mixing Pump HSW Feed Pumps 38

39 FEEDING SUBSTRATES HSW Receiving Tank Level (FT) ~90 Minutes HSW Storage Tank Level (FT) ~90 Minutes HSW Pump Set Point (GPM) D6 Gas Pressure (IWC) HSW Feed (GPM) ph (s.u.) Strainer Plugged Strainer Unplugged 39

40 FEEDING SUBSTRATES HSW Receiving Tank Level (FT) HSW Storage Tank Level (FT) HSW Pump Set Point (GPM) D6 Gas Pressure (IWC) HSW Feed (GPM) ph (s.u.) 40

41 CHALLENGES OF CO-DIGESTION Adds Complexity to Plant Operations If you are going to Maximize Biogas production Anaerobic Digestion requires daily monitoring, we monitor ph Requires Analyzing Waste Streams for Chlorides Requires Mixing the HSW Storage Tank to Homogenize Blended Wastes Smells Different Odors are not worse just different Milk house odors, Cheese odors, fermentation odors HSW can be corrosive Usually has a Low ph <5.0 s.u. Requires corrosion resistant materials (SS pumps, glass lined pipe, CPVC, etc ) Can Increases Biosolids Production (sludge) HSW Streams Come and Go HSW Generators look for the Least Expensive Disposal Cost 41

42 BENEFITS OF CO-DIGESTION Uses Available Plant Capacity Sheboygan WWTP Plant Loading was 60% - 65% in 2005 The wet end is still at 60% -65 % Loading However we are using nearly all of the AD capacity Increases Biogas Production % Can Reduce Natural Gas Purchases Sheboygan Natural Gas Purchases dropped by >90% Provides Fuel for Onsite Power Generation, 700 kw Generation Capacity At times Sheboygan WWTP can generate all of its Electrical Energy Onsite Provides Additional Revenue from Tipping Fees For Sheboygan HSW revenue range from $200,000 to $400,000 annually Rates cannot be based on the BOD, TSS or P content of the waste, rates must be competitive as the generator will look for the least costly alternative for disposal 42

43 BENEFITS OF CO-DIGESTION 43

44 BENEFITS OF CO-DIGESTION 44

45 BENEFITS OF CO-DIGESTION 700 kw Generating Capacity kw Capstone Microturbines kw Capstone Microturbines 4 Cain Heat Exchangers Generally produces between 70% and 90% of our electricity requirements May 5 th 2011 was Energy Independence Day. The first day we became a net exporter of electricity to the grid. 45

46 BENEFITS OF CO-DIGESTION 93.2 % of Electricity Produced Onsite on 02/12/2013 Gross kwh Produced Parasitic Load Net kwh Produced Gross kwh Produced Parasitic Load Net kwh Produced 46

47 BENEFITS OF CO-DIGESTION Anything below the green line is turning the electric meter backwards 47

48 BENEFITS OF CO-DIGESTION 7,000,000 Sheboygan WWTP Electrical Energy Purchased From Grid 6,000,000 5,000,000 Annual Kilowatt Hours 4,000,000 3,000,000 2,000,000 1,000,

49 HSW PROGRAM AND ENERGY PROJECTS REDUCES PURCHASED POWER 2012 Electrical Savings $366,000 ($0.0995/kWh)* * Includes Demand Charges Natural Gas Savings $75,000 ($0.45/Therm) HSW Revenue $296,800 Net = $737,800 Purchased Electricity, kwh/mgal Wisconsin Focus On Energy Best Practices Benchmark WFE

50 PROJECT PAYBACK Project Project Cost Other Funding City s Cost Payback Co-Digestion $75,000 $0 $75,000 <1 Year Sludge Boiler $350,000 $0 $350,000 <5 Years COGEN Phase I $1,200,000 $899,000 Alliant Energy COGEN Phase II $1,500,000 $205,000 Grant $301,000 <3 Years $1,295,000 5 Years 50

51 SUMMARY We started tinkering with co-digestion in 2004 & 2005 using available digester capacity to increase tipping fee revenues and biogas production Co-digestion became a permanent operation after the installation of the 30 kw microturbines in 2006 when we needed additional biogas There were many lessons learned over the first few years, we learned: How to operate and AD system at a high organic loading rate How to monitor AD performance using ph instead of Volatile Acids & Alkalinity How to deal with different types of wastes, limiting high chloride waste, diluting wastes with high solids and screening waste with non-ready biodegradables and other trash How to match biogas production to biogas demand How to maintain a steady supply of HSW How to determine Tipping Fee Rates Our experience with co-digestion provided us with an opportunity to use available plant capacity to increase revenues while reducing operating costs 51

52 BOOSTING BIOGAS PRODUCTION WITH CO-DIGESTION Dale L. Doerr MBA Sheboygan Regional WWTP Three Business Models for Organic Waste to Energy Webinar - March 6, 2013

53 George P. Dreckmann City of Madison, WI

54 230,000 people Public Collection Multifunction agency Operators also plow snow in winter 66,000 Households Serve properties with 8 units or less Small Business Customers

55 Weekly curbside collection of source separated organics Biweekly or monthly collection of residual Material taken to an anaerobic digester Biogas for electrical generation and CNG Digestate composted with yard waste Large organic farming market within region

56 Better Suited for Wisconsin s Climate Renewable Energy Control Over Large Portion of Our Waste Control Over Some Energy Costs

57 $12 to $25 Million Capital Costs Low Operating Costs Generate Energy on Site Small Staff Study Showed Cost Per Ton of $42 to $86 Current Landfill Tipping Fee $42

58 General Obligation Bonds=Low Interest Rate Currently borrowing between 1.75% and 3% AAA Bond Rating Adequate Borrowing Capacity No Need To Generate Profit Be Competitive With Other Disposal Options

59 Tipping Fees From Other Entities Private Sector Users Other Communities Digestate Sales $250,000 Annually Carbon Credits $20,000 Annually Electrical Sales Short Term RIN Credits $1 per gallon $170-$350,000 annually

60 Landfill Tipping Fees $ ,000 Diesel Fuel Costs 200,000 to 375,000 gallons of diesel equivalent $700,000 to $1,312,500 annually

61 Debt Service $3,000,000 ($25 million at 3%) Operating and Maintenance Costs $ 850,000 Revenue $470,000 (No Tip Fees) Avoided Costs $1,600,000

62 George Dreckmann

63 Questions Questions? Amy Bolten (707)