MERRIMACK VALLEY BIOMASS FUEL STUDY

Transcription

1 MERRIMACK VALLEY BIOMASS FUEL STUDY September 10, 2008 Loudon Elementary School Penacook Elementary School Boscawen Elementary School

2 MERRIMACK VALLEY BIOMASS FUEL STUDY TABLE OF CONTENTS A. B. C. D. E. F. Executive Summary System Choice Fuel Choice Building Enclosures/ Stack Available Vendors Site Analysis Penacook Boscawen Loudon Existing Building Analysis Penacook Boscawen Loudon Project Costs Penacook Boscawen Loudon Life Cycle Cost Analysis Summaries Penacook Boscawen Loudon APPENDIX 1. Life Cycle Cost Worksheets 2. Wood Boiler Sizing - Partial Load Bin Analysis

3 EXECUTIVE SUMMARY - A1 Black River Design and Kohler & Lewis reviewed three elementary school sites - Penacook, Boscawen and Loudon - for the purpose of evaluating the feasibility of installing a biomass heating system to serve as the primary heating plant for each facility. Both woodchip and wood pellet options were considered. All three schools are relatively new or newly renovated buildings served by existing modernized, efficient and well controlled hot water heating systems. Penacook and Boscawen use natural gas and Loudon uses #2 fuel oil. Both Penacook and Boscawen will be able to accommodate either a woodchip or a pellet system. The larger woodchip building pushes to the limit of the available space at Penacook, but more easily accommodates the truck access required for the woodchip deliveries. Boscawen has more real estate available for the building but a tighter route for chip delivery. The proposed sites at Penacook will be visible from the entrance drive, but enjoy easy access to the boiler room. The proposed site at Boscawen is behind the school, is close to the existing boiler room, and will not alter the public view of the building. While feasible to install a woodchip building at Loudon, it will be quite remote from the boiler room and require more complicated sitework and a long run of underground piping as well as a long overhead piping route through the building. The smaller pellet system will easily fit on the existing paved apron near the boiler room and kitchen entrance. The pellet boiler can be located either in a freestanding enclosure or be installed inside the existing boiler room. The Life Cycle Cost Analysis indicates a very favorable payback for Loudon where the current fuel is heating oil. These results translate into a recommendation to move forward with a biomass project as soon as possible. Due to the lower initial cost, the reduced disruption to the rest of the site and existing building, and a lower payback over the first 10 years, the recommendation is to proceed with one of the pellet options rather than the woodchip option. The payback is less certain at both Penacook and Boscawen where the biomass fuel will be replacing natural gas. When using the current gas cost of $1.534 per therm, fuel costs per million BTU s are roughly the same as for pellets. The higher initial costs for woodchip systems result in a very low payback for those systems.. Boscawen performs only slightly better than Penacook in the analysis. A second set of worksheets has been prepared assuming an initial cost of gas at approximately the midpoint between the current cost of gas and the current cost per BTU of fuel oil. The results indicate a more positive payback scenario.

4 EXECUTIVE SUMMARY - A2 Both Penacook and Boscawen suffer in this analysis from both the slow reaction of the (regulated) cost of natural gas to the rising cost of fuel oil and the relatively high energy efficiency performance of the existing buildings and heating systems. If the current cost of natural gas holds steady or increases slowly, moving forward with a biomass project at these sites would be a relatively cost neutral endeavor at best. When deciding between woodchips and pellets, a couple of points should be kept in mind. For buildings of this size and type - medium size school buildings - woodchip systems are a proven solution with dozens of systems from multiple vendors on-line throughout the region. Intermediate size pellet systems are an emerging force in the industry and are used outside of this region in portions of Europe. Vendors are fewer and less proven in northern New England. Secondly, woodchips are a less processed fuel and are potentially more flexible and able to react more quickly to changes in demand.

5 SYSTEM CHOICE - B1 FUEL CHOICE There are two types of biomass fuels considered for this analysis. One fuel is wood pellets which are manufactured from compressed sawdust. The other option is woodchips. Wood pellets have a lower moisture content than woodchips and have a higher energy density, but are also more energy intensive to produce and therefore more expensive. Woodchip boilers are larger and more expensive than wood pellet boilers and require a larger building to store the woodchips so the initial investment is greater. Pellet silo Wood chips have an energy content of 10,900,000 Btu/ton, a moisture content of 45% and burn at a typical efficiency of 65%, delivering about 6,000,000 Btu/ton. Pellets have an energy content of 16,800,000 Btu/ton, a moisture content of 3% and burn at 88% efficiency in modern boilers, delivering 14.3 MM Btu/ton. Since pellets produce about twice the energy per ton, the storage space required is approximately half as large. And, since agricultural silos are used, the cost for storage is much less than for woodchips. Conveying pellets from Storage to the boiler is much simpler and less maintenance is involved. Augers are used instead of conveyers, and pellets are a uniform size. Both systems have similar emissions for a given size boiler. For boilers less than 2,000,000 Btu/hr, pellet boilers typically have a stack height of 25 or 4 above the eave of a nearby building. In Europe stack heights are typically 5 taller. Woodchip bin Wood chips are more universally available than pellets and the cost is much less at $50-$60 per ton verses $250 per ton for pellets that yield costs after combustion of $8.33/MM Btu for woodchips and $17.43/MM Btu for pellets. For comparison, oil at $4.5/gallon is $39.29/MM Btu. So woodchips are half the cost of pellets and about one fifth the cost of oil per Btu delivered. Generally for small systems less than 2,000,000 Btu/hr pellets make much more sense as the infrastructure costs for chip storage and handling are too high. For systems greater than 5,000,000 Btu/hr, chip systems usually make the most sense. Woodchips are widely available. There are two major pellet suppliers serving New Hampshire and Vermont: New England Pellet in Jaffrey, NH and Energex in Lac Megantic, Quebec. There are also at least three smaller plants in Maine and a plant in Syracuse, NY and more plants are coming on line.

6 SYSTEM CHOICE - B2 BUILDING ENCLOSURE Woodchip Building: Boiler room and bunker should be insulated but can be most any construction type - wood, masonry, metal insulated panel. Size of the building depends on vendor selection but typically is approximately 20 wide and 30 to 40 long. Woodchip Storage - below grade: A 20 x 40 bunker, 15 to 20 deep is required as well as an auger system to lift the chips back to grade level where the boiler is located. Space eating egress stairs and the complicated auger system and/or ash removal is not necessary where the bunker can be built into a sloped topography and the boiler can be located in a basement. This option requires massive heavily reinforced concrete walls. These buildings typically have two overhead doors to allow the bunker to be refilled on one side before the other is entirely empty. On grade woodchip storage On grade woodchip storage Woodchip Storage - at grade: A long narrow bay 25 x 60 is constructed at grade to allow back to front filling of the storage area as the delivery truck pulls forward. Chips are used from front to back and a new delivery is made once there is adequate room for a complete load. Woodchip storage bunker Below grade woodchip storage Below grade woodchip storage

7 SYSTEM CHOICE - B3 Pellet building: A smaller insulated pre-manufactured metal building approximately 12 x 20 is recommended. Other custom construction types would be feasible. Pellet storage is in a separate 10 diameter silo, 25 tall. In some cases there is adaquate space in the existing building to house the new pellet boiler, requiring additional exterior space be allocated only for the new storage silos Stack: Stacks for woodchip systems have grown taller in recent years. On projects requiring air quality permits, modeling has indicated that stacks as tall as 65 are necessary to assure acceptable dispersion of particulates and gaseous emissions. Shorter stacks may be possible depending on site specific conditions. There is no generally accepted scientific evidence that pellets or woodchips burn significantly cleaner than the other. Similar assumptions for stack size should be made for both pellet and woodchip options until further investigations indicates otherwise. No air quality permit is required in New Hampshire for systems with a boiler input capacity of less than 2 million BTU s. None of the potential systems discussed in this study exceed this limit. Interior pellet boiler with exterior silos 65 foot stack Low profi le woodchip stack

8 SYSTEM CHOICE - B4 AVAILABLE VENDORS Woodchip: There are three vendors active in the northern New England region providing automated woodchip systems to school districts. Black River Design will have completed projects with all three in the last 12 months. These vendors, with recently completed Black River Design projects are: Bio-Fuel Technologies, - Danville School 1. Bio-Fuel Technologies, LLC, Beaverton, PA (Danville School) 2. Chiptec, Inc., Williston, VT (Cabot High School; Richford Middle / High School) 3. Messersmith Manufacturing, Bark River, MI (Lamoille Union Middle High School; Howard Dean Education Center, Mt. Wachussett Community College) We have found that with three competitive vendors, Owners have been the beneficiary of some very favorable and predictable pricing over the last 18 months. Chiptec, Inc. - Hazen Union High School Messersmith Manufacturing - Lamoille Union Middle/High School Pellet Boilers: Most of the experience with Pellet Boilers in New England are with the Tarm Baxi boiler, an imported residential boiler with heat output of approximately 150,000 Btu/hr. While larger size pellet boilers are widely used in Europe, they are only beginning to be imported to the U.S. and there is little operating experience with these boilers in this country. New England Pellet systems in Jaffrey, NH is importing a line of Swebo Boilers made in Sweden. Viessman is also introducing a pellet boiler to this area. Modern European boilers are efficient (up to 88%) and have automatic ash removal and automatic cleaning and sophisticated controls. Larger boilers include cyclones for cleaning the gasses. These boiler have emissions that are about 1/100 of current standards though these standards are expected to become more stringent. One difficulty with European boilers is that they do not carry the ASME label, which is required for all pressure boilers in commercial and institutional buildings. In New Hampshire these boilers may be used if operated as atmospheric boilers but this requires a heat exchanger and an additional pump. Some American manufacturers such as Burnham sell solid fuel ASME boiler that carry the ASME label, but their burners may not be as sophisticated as the European boilers.

9 SITE ANALYSIS - C1 PENACOOK Penacook - Gym location There are two areas near the existing boiler room to locate a woodchip/ pellet building - behind the gym (either attached or free standing) and between the far classroom wing and the service drive. Both are easily accessible from the service drive and since the drive circumnavigates the school both will be easily served by fuel delivery vehicles. The site behind the gym is restricted by underground gas, electric and water utilities, making the smaller pellet building more viable than a woodchip facility. Either fits easily behind the classrooms. The lack of underground utilities also makes locating the underground heating mains for the biomass system from behind the classrooms simpler than from the gym location. It is a slightly longer run from the classroom location to the boiler room. This difference has little impact on the long-term cost analysis. Locating the new boiler behind the classrooms will limit options for future expansion of the classroom wing. This report analyzes two pellet options and one woodchip option. Penacook - Classroom location BOSCAWEN This site is well suited to either a pellet or woodchip installation. There is level ground in near proximity to the existing boiler room. The proposed site is at the edge of existing open play areas and will not interfere with current educational site utilization. A detached boiler room for the biomass system is recommended to avoid disrupting existing underground utilities, stormwater drainage, service access or building egress. Like at Penacook, the service drive extends all the way around the building and provides good access for fuel delivery vehicles. Avoiding existing underground utilities into the boiler room is very feasible. Boscawen - location This report analyzes one pellet option and one woodchip option. LOUDON Siting a pellet system at this site is much more feasible than locating a woodchip facility. The best potential location for a woodchip system is on the hill on the other side of the service drive beyond the gym. This solution would require significant sitework, underground heating main runs and a long run through the building to the boiler room. There are two viable pellet options. The first is to locate the silo and building enclosure on the existing paved apron just outside the existing boiler room. The second is to locate the silo here but to omit the building enclosure and place the new pellet boiler inside the existing boiler room. Loudon - location This report analyzes two pellet options and one woodchip option.

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16 EXISTING BUILDING ANALYSIS - D1 PENACOOK Loudon - proposed pellet boiler locaton The Penacook Elementary School (PES) was built in 2001 and has a floor area of 66,000 square feet. The school is heated by two natural gas fired, Weil-Mclain 1188 boilers rated at 2.7 MMBTU each. The boilers are injection pumped into the main building hot water loop. Therefore a biomass boiler plant can be connected to the loop without the need for any piping changes on the existing system. Fuel usage data for the last three years indicate that the school has used an average of 22,616 therms of natural gas per year at an average annual cost of $31,561 per year. The natural gas is used for cooking and domestic hot water generation as well. BOSCAWEN Boscawen - existing boiler The Boscawen Elementary School (BES) was built in 1996 and has a floor area of 55,000 square feet. The school was originally heated with propane but was converted to natural gas in The school is served by a single Smith 28-A-7 boiler rated at 1.47 MMBTU. Boscawen Elementary uses an average of 23,335 therms of natural gas per year. This includes heating, domestic hot water generation and kitchen usage. Boscawen - existing piping Loudon - existing boiler Penacook - existing piping LOUDON The Loudon Elementary School (LES) is approximately 58,640 square feet including a 2007 addition which added 18,000 square feet to the school. The building is primarily masonry construction and is made up of the original 1860 building and additions that were added in 1954, 1988, 1990 and The Loudon school is heated with oil and used 14,454 gallons of oil last year (the first year with the latest addition). As part of that addition a Hydrotherm model M01925 boiler plant rated at 1.53 MMBTU was installed in the fall of This boiler serves all of the school except for the 2001 addition which is served by a 2 x 4 boiler (with a Carlin 301CRD-W burner) rated at approximately.5 MMBTU. According to the plant manager the loops are piped together but isolated and operated as two separate loops. In Loudon School the pellet boiler can be located in the existing water room next to the boiler room. Since Loudon does not have a primary secondary piping system, some repiping of the existing system will be required.

17 EXISTING BUILDING ANALYSIS - D2 Connection to the existing boiler, is done by a primary/secondary or injection system. In this system the wood boiler connects to the piping main upstream of the fossil fuel boilers. Water is pumped through the wood boiler, heated and injected back into the main. Pellet systems that are not ASME rated require a heat exchanger. Typical piping is shown in the attached figures.

18 PROJECT COSTS - E1 PROJECT COSTS The attached project cost summaries for each site use the following assumptions Woodchip equipment: Based on recent bidding results and moderate inflation, the woodchip equipment provided by the supplier/manufacturer (boiler, gasifier, cyclone, augers, metering bins, etc.) is assumed to be $300,000. Final sizing of the system will result in small adjustments to this estimate. The budget includes a 65 freestanding stack. Pellet equipment: An assumption of $190,000 has been made based on quotes from a vendor for a combination equipment/enclosure package. The enclosure price has been broken out separately for comparison purposes. The budget includes a stack. Woodchip building enclosure: The budget figures included here represent an on-grade insulated metal sided building large enough to hold truckloads of chips plus the boiler room. These figures are again based on recent bidding results for similar structures. The budget for an in ground bunker storage facility would be approximately $150,000 more. Pellet building enclosure: This budget represents the vendors estimate for the pre-manufacturered metal insulated enclosure, the pellet silo, a separate poured concrete foundation and slab, and an allowance for an increased stack size and additional building features not included in the standard box. Stormwater disposal: Most of the proposals assume a pitched roof which will shed stormwater onto the site, which will need to be dealt with. A similar allowance has been included for all sites and all options except for the pellet options at Loudon, where it has been reduced (Option P10) or eliminated (Option P2). GC general conditions, mark-up and bond: These are costs associated with general contractor costs for supervision, coordination, and miscellaneous equipment and supplies needed for completion of the project. Use of a percentage allowance based on the construction cost reflects the lesser coordination requirements and shorter construction duration for the pellet options.

19 PROJECT COSTS - E Fees: Consultant fees have likewise been reduced for the pellet options due to the reduced complexity of the system. Permits, other miscellaneous costs: These costs are less dependent on the size or complexity of the project. Some of them include insurance, Clerk of the Works, hazardous materials testing, etc. A fixed allowance has been included for all options. Contingency: A reasonable contingency must be included. A minimum of 10% is recommended at this early stage when so few specific details are known. Typically a contingency can be reduced as a project moves toward completion. This contingency is meant to cover both the inaccuracies inherent in an estimate and the additional unforeseen costs always experience with any construction project.

20 PROJECT COSTS - E3 Penacook Elementary School Preliminary Project Budget Worksheet Woodchip system equipment Building enclosure - boiler and fuel storage Woodchip #1 (W1) $300,000 $175,000 Woodchip #2 (W2) Pellet #1 (P1) $190,000 $40,000 Pellet #2 (P2) $190,000 $40,000 Stormwater disposal $5,000 $3,000 $3,000 Other site work $1,000 $1,000 $1,000 Additional new mechanical system components $35,000 $27,500 $27,500 Mechanical controls $7,500 $7,500 $7,500 Underground utility extensions $11,250 $9,750 $7,500 trench & patch paving $1,000 $1,000 $1,000 Electrical - new mech. equipment hookup $20,000 $10,000 $10,000 Electrical - other $20,000 $10,000 $10,000 GC general conditions, mark-up and bond $57,575 $29,975 $29,750 Construction estimate total $633,325 $329,725 $327,250 Fees $75,000 $60,000 $60,000 Permits, other miscellaneous costs $35,000 $35,000 $35,000 Contingency $63,333 $32,973 $32,725 TOTAL PROJECT BUDGET $806,658 0 $457,698 $454,975 Remarks Vendor price Insulated metal building, and on-grade chip storage for woodchip options/silo for pellet options, including excavation for foundations Runoff from pitched roof Lawn restoration, move existing utilities, etc. New and existing boiler rooms $150/ft $10/ft ($1000 min) Assume 10% Allow 10%

21 PROJECT COSTS - E4 Boscawen Elementary School Preliminary Project Budget Worksheet Woodchip system equipment Building enclosure - boiler and fuel storage Woodchip #1 (W1) $300,000 $175,000 Woodchip #2 (W2) Pellet #1 (P1) $190,000 $40,000 Pellet #2 (P2) Stormwater disposal $5,000 $3,000 Other site work $1,000 $1,000 Additional new mechanical system components $35,000 $27,500 Mechanical controls $7,500 $7,500 Underground utility extensions $11,250 $9,750 trench & patch paving $1,000 $1,000 Electrical - new mech. equipment hookup $20,000 $10,000 Electrical - other $20,000 $10,000 GC general conditions, mark-up and bond $57,575 $29,975 Construction estimate total $633,325 $329,725 Fees $75,000 $60,000 Permits, other miscellaneous costs $35,000 $35,000 Contingency $63,333 $32,973 TOTAL PROJECT BUDGET $806,658 0 $457,698 Remarks Vendor price Insulated metal building, and on-grade chip storage for woodchip options/silo for pellet options, including excavation for foundations Runoff from pitched roof Lawn restoration, move existing utilities, etc. New and existing boiler rooms $150/ft $10/ft ($1000 min) Assume 10% Allow 10%

22 PROJECT COSTS - E5 Loudon Elementary School Preliminary Project Budget Worksheet Woodchip system equipment Building enclosure - boiler and fuel storage Interior piping and restoration Woodchip #1 (W1) $300,000 $200,000 Woodchip #2 (W2) Pellet #1 (P1 - outside) $190,000 $40,000 Pellet #2 (P2 - inside) $190,000 $10,000 Stormwater disposal $5,000 $3,000 Other site work $15,000 $1,000 $1,000 Additional new mechanical system components $35,000 $32,500 $47,500 Mechanical controls $7,500 $7,500 $7,500 Underground utility extensions $22,500 $9,750 trench & patch paving $1,500 $1,000 $1,000 Electrical - new mech. equipment hookup $20,000 $10,000 $15,000 Electrical - other $20,000 $10,000 $1,000 GC general conditions, mark-up and bond $62,650 $30,475 $27,300 Construction estimate total $689,150 $335,225 $300,300 Fees $75,000 $60,000 $60,000 Permits, other miscellaneous costs $35,000 $35,000 $35,000 Contingency $68,915 $33,523 $30,030 TOTAL PROJECT BUDGET $868,065 0 $463,748 $425,330 Remarks Vendor price, excludes silo Insulated metal building, and on-grade chip storage for woodchip options/silo for pellet options, including excavation for foundations Runoff from pitched roof Lawn restoration, move existing utilities, etc. New and existing boiler rooms $150/ft $10/ft ($1000 min) Assume 10% Allow 10%

23 LIFE CYCLE COST ANALYSIS - F1 PENACOOK CURRENT FUEL SUMMARY FUEL TYPE: NATURAL GAS Annual Consumption: 22,500 Gallons Cost Per Gallon: $1.534 (Represents current contracted cost) PELLET Projected Cost: $250 per ton TOTAL PELLET SYSTEM COST: $457,698 Annual First Year Natural Gas Cost $34,515 Annual Projected Combined Pellet/Gas Cost $34,509 Annual Fuel Savings $6 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance ($994) SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid NO PAYBACK 20.9 YEARS 15.9 YEARS WOODCHIP Projected Cost: $59 per ton TOTAL WOODCHIP SYSTEM COST: $806,658 Annual First Year Natural Gas Cost $34,515 Annual Projected Combined Woodchip/Gas Cost $19,693 Annual Fuel Savings $ 14,822 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $ 13,822 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 58.4 YEARS 19.8 YEARS 13.1 YEARS

24 LIFE CYCLE COST ANALYSIS - F2 PENACOOK CURRENT FUEL SUMMARY FUEL TYPE: NATURAL GAS Annual Consumption: 22,500 Gallons Cost Per Gallon: $2.52 (Represents cost midway between current gas cost and current oil cost) PELLET Projected Cost: $250 per ton TOTAL PELLET SYSTEM COST: $457,698 Annual First Year Natural Gas Cost $ 56,700 Annual Projected Combined Pellet/Gas Cost $22,191 Annual Fuel Savings $6 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $21,191 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 21.6 YEARS 11.7 YEARS 6.9 YEARS WOODCHIP Projected Cost: $59 per ton TOTAL WOODCHIP SYSTEM COST: $806,658 Annual First Year Natural Gas Cost $56,700 Annual Projected Combined Woodchip/Gas Cost $19,928 Annual Fuel Savings $36,772 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $35,772 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid YEARS 13.1 YEARS 7.6 YEARS

25 LIFE CYCLE COST ANALYSIS - F3 BOSCAWEN CURRENT FUEL SUMMARY FUEL TYPE: NATURAL GAS Annual Consumption: 23,352 Gallons Cost Per Gallon: $1.534 (Represents current contracted cost) PELLET Projected Cost: $250 per ton TOTAL PELLET SYSTEM COST: $457,698 Annual First Year Natural Gas Cost $35,822 Annual Projected Combined Pellet/Gas Cost $35,817 Annual Fuel Savings $5 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance ($995) SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid NO PAYBACK 20.3 YEARS 15.4 YEARS WOODCHIP Projected Cost: $59 per ton TOTAL WOODCHIP SYSTEM COST: $806,658 Annual First Year Natural Gas Cost $35,822 Annual Projected Combined Woodchip/Gas Cost $20,477 Annual Fuel Savings $15,345 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $14,345 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 56.2 YEARS 19.6 YEARS 12.3 YEARS

26 LIFE CYCLE COST ANALYSIS - F4 BOSCAWEN CURRENT FUEL SUMMARY FUEL TYPE: NATURAL GAS Annual Consumption: 23,352 Gallons Cost Per Gallon: $2.52 (Represents cost midway between current gas cost and current oil cost) PELLET Projected Cost: $250 per ton TOTAL PELLET SYSTEM COST: $457,698 Annual First Year Natural Gas Cost $58,848 Annual Projected Combined Pellet/Gas Cost $36,670 Annual Fuel Savings $22,178 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $21,178 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 21.6 YEARS 11.6 YEARS 6.2 YEARS WOODCHIP Projected Cost: $59 per ton TOTAL WOODCHIP SYSTEM COST: $806,658 Annual First Year Natural Gas Cost $58,848 Annual Projected Combined Woodchip/Gas Cost $20,775 Annual Fuel Savings $38,073 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $37,073 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 21.8 YEARS 12.3 YEARS 7.4 YEARS

27 LIFE CYCLE COST ANALYSIS - F5 LOUDON CURRENT FUEL SUMMARY FUEL TYPE: #2 FUEL OIL Annual Consumption: 14,449 Gallons Cost Per Gallon: $4.37 (Represents current contracted cost) PELLET TOTAL PELLET SYSTEM COST: $463,748 Projected Cost: $250 per ton Annual First Year Fuel Oil Cost $63,143 Annual Projected Combined Pellet/Oil Cost $29,213 Annual Fuel Savings $33,930 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $32,930 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 14.1 YEARS 9.3 YEARS 5.1 YEARS WOODCHIP Projected Cost: $59 per ton TOTAL WOODCHIP SYSTEM COST: $868,065 Annual First Year Fuel Oil Cost $63,143 Annual Projected Combined Woodchip/Oil Cost $21,026 Annual Fuel Savings $41,518 Annual Maintenance Cost (Todays Dollars) $1000 Annual Energy Savings Less Maintenance $40,518 SIMPLE PAYBACK (Savings less O&M) ADJUSTED SIMPLE PAYBACK with 55% State Aid 20.0 YEARS 12.6 YEARS 7.2 YEARS

28 LIFE CYCLE COST ANALYSIS - F6 PAYBACK SUMMARY EXISTING FUEL TYPE & COST BIOMASS FUEL TYPE SIMPLE PAYBACK Total cost / 1st year savings + annual maintenance ADJUSTED PAYBACK Simple payback adjusted for annual fuel inflation ADJUSTED WITH STATE AID Adjusted payback assuming 55% State Construction Aid current (lower) gas cost $1.534/therm Pellet projected (higher) gas cost $2.52/therm Pellet Chip NONE current (lower) gas cost $1.534/therm Pellet projected (higher) gas cost $2.52/therm Pellet Chip NONE current #2 fuel oil cost $4.37/gallon Pellet Chip

29 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.1 ENERGY ANALYSIS. Kohler & Lewis has investigated the feasibility of installing biomass heating systems for the Penacook (PES), Boscawen (BES) and Loudon Elementary schools (LES). The analyses will be presented in detail for the LES. The same methodology will be applied to the BES and PES. Determination of the design heating load is the first step in this analysis. While this is usually done by performing a heat loss calculation, that method includes many assumptions involving infiltration and ventilation which are very difficult to predict. An alternative approach is to estimate the design heat load from the annual energy use according to the following formula: Q = UA*24*DDA qe = UA ΔT UA = Overall heat transfer coefficient (Btu/hr ft2) DDA = Adjusted degree days (ºF-day) ΔT = Design temperature difference (ºF) Q = Annual energy use (Btu/yr) q = design heat loss (Btu/hr Rearranging q = (Q annual) (24 x DDA) Assuming oil is connected to heating the building at 83% efficiency, for the LES: Q = 14,454 gal/yr x 138,000 Btu/gal x.83 = 1,655,561,000 Btu/yr Assuming DDA, adjusted for internal gains and a night setback; is 6000 and the design temperature difference is 90ºF q = 1,655,561,000 x 90 = 1,034,725 Btu/hr 24 x 6000 The biomass boiler does not necessarily need to be sized to meet the full design load since there is a back-up oil boiler. A smaller boiler will cost less and still offset most of the oil use. The percent of oil use offset is a function of the percent of the design load met by the pellet boiler as presented in Appendix 2.

30 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.2 FUEL AND MAINTENANCE COSTS: It is very difficult to predict the cost of either fossil or biofuels. Over the long term, oil prices have increased about 3% per year above general inflation. However, the escalation has been much more rapid recently, increasing almost 450% in the last 10 years and almost 100% in the last year. In the same time frame wood pellet cost has increased 59% and 10%, respectively. For the purposes of this analysis, oil was assumed to cost $4.37/ gallon. Natural gas was assumed to be $1.534/therm. Natural gas currently costs about half as much as oil per million BTU because of the high rate of inflation for oil over the past several years. However, historically natural gas prices have been very similar to oil (per million BTU). Therefore a second analysis was performed assuming that natural gas prices escalate towards the price oil. For the second analysis the initial price of natural gas was assumed to be $2.52/therm, which is approximately halfway between the current cost of natural gas and the cost of oil (in terms of cost per BTU). Pellets and woodchips were assumed to cost $250/ton delivered and $59/ton respectively and inflate at 3.5% each. Additional maintenance costs for the biofuel systems were assumed to be an initial cost of $1,000, increasing at a general inflation rate of 4% per year. FINANCING: Financing costs were not factored into this analysis. If they were to be considered for this analysis, it would be assumed that bond payments would be done with a level principal payment. The principal would be spread evenly over the length of the bond and the payments decreased over time as the interest portion of the payment goes down. The State of New Hampshire offers aid for capital improvements for public schools in the amount of 55% of the total project cost. This money is paid out in the form of 55% of the principal amount of each payment during the full term of the bond.

31 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.3

32 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.4

33 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.5

34 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.6

35 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.7

36 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.8

37 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.9

38 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.10

39 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.11

40 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.12

41 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.13

42 LIFE CYCLE COST ANALYSIS WORKSHEETS - APPENDIX 1.14

43 WOOD BOILER SIZING ANALYSIS - APPENDIX 2.1 INTRODUCTION Boilers are usually sized based on the heating load of the building or buildings that they serve. The engineer will evaluate the heating load, factor in a degree of safety and select a boiler or boilers that will maintain the building at a the design temperature on even the coldest days of the year. In this case the boiler is sized to provide 100% of the annual heating energy. In recent years, as energy costs have risen, the use of alternative fuel boilers such as those burning wood chips or pellets has become more prevalent. These boilers are often used as the primary boiler with a secondary fossil fuel boiler to provide additional heating capacity and back-up. In these cases, or other situations where the boiler size does not need to meet the full design heating load, it can be useful to evaluate the boiler size based on the percent of the annual heating load met by the boiler. ANALYSIS To answer this question a bin analysis was performed using weather data for Concord, NH TMY. The building was assumed to be a school and the temperature data was grouped into occupied and unoccupied periods so that internal gains could be factored into the heating load during occupied periods and night setback could be factored for the unoccupied period. The weather data was sorted using BinMaker Pro by InterEnergy. ASSUMPTIONS: Design Outside Air Temperature = -7 ºF Design Load = 50 Btuh/sq-ft Internal Gains = 5.5 Btu/sq-ft Lighting Density: 1 watt/sq-ft = Btuh/sq-ft Occupant Density: 200 Btuh/person; 20 people/2,000 sq-ft Occupied Period: 7am-5pm, M-F, September-June Occupied Setpoint = 72 ºF; Unoccupied Setpoint = 55 ºF The bin temperature data is grouped by temperature and occupancy period. For each bin the outside air temperature is compared to the design outside air temperature and the percent of design load was calculated. During the occupied period the percent of design load is adjusted for internal gains and the number of load hours is

44 WOOD BOILER SIZING ANALYSIS - APPENDIX 2.2 determined. For example, during the occupied period there are 100 hours per year when the temperature is between 54 and 56 ºF and the adjusted percent of design load at this temperature is 11% which results in about 10.5 load hours for this bin. The next step is to determine how many of the annual load hours will be met by a given boiler size as the sizes range from 10% to 100% of the design heating load. This is determined by comparing the design heating load to the boiler size and calculating the number of hours met for each boiler. By comparing the total annual load hours to the annual load hours met the percent of heating load met is calculated for each boiler size. RESULTS The results for this analysis indicated a steady, almost linear increase in percent of load met from 25 to 90% as the boiler size increase from 10% to 50% of the design load. Increasing the boiler size to 60% of the design load will satisfy an additional 5% of the annual heating load, but further increases in boiler size provide minimal benefit. The results of this analysis are encouraging for building owners who want to decrease their fuel costs by installing an alternative heat boiler. It demonstrates that by adding a boiler equal to only half of the design heating load, fossil fuel usage can be reduced by about 90%. Since alternative fuel boilers can increase dramatically in cost as their capacity increases these results could be useful for owners trying to make a cost effective boiler selection.