G-027-230-010 BIOMASS HEATING SYSTEM SPECS & DRAWINGS.pdf

Wood Energy Technical Assistance Team

Eastern Region WERC Wood Energy Technical Assistance Team

DRAFT Memorandum

DATE: June 3, 2022

TO: Benjamin Degenhard, MD Department of Natural Resources

FROM: Peter Oven & John Pavlakovic, USFS Wood Energy Technical Assistance Team

CC: Andrew Hady, MD Department of Natural Resources; Lew McCreery, USFS Wood Energy Technical Assistance Team; Daniel Rider, MD Department of Natural Resources; Maura Ross, MD Clean Energy

RE: Cypress Branch NRMA Biomass Heating System Recommendations

1.0 INTRODUCTION

The Cypress Branch Natural Resource Management Area (NRMA), located on 10701 Galena Rd. Millington, MD, is a state park and recreational area that is maintained by the Maryland Department of Natural Resources (MD DNR). The site was originally purchased at 274 acres in area and now consists of 314 acres of cropland, meadows, forested areas, and marshes. Within the park, there is a building that was originally an old farm barn and has since been undergoing renovations to turn the building into an office and workshop area for park employees. This memorandum evaluates how the Cypress Branch NRMA could add or improve heating systems for its workshop building by utilizing woody biomass. Biomass heating would reduce net greenhouse gas emissions compared to using fossil fuels, while utilizing a local, sustainable fuel source and keeping energy expenditures in the local economy.

2.0 FACILITY OVERVIEW

WERC met virtually with Cypress Branch NRMA supervisor Benjamin Degenhard on April 11, 2022, in order to become familiar with the site layout and scope of the proposed renovations.

2.1 WORKSHOP BUILDING

The workshop building is a 5,680 square foot, single story pole building built in 1984, with metal siding and a metal panel roof that has been undergoing renovations to convert the building into an office/workshop area for Cypress Branch NRMA employees. Currently, the building is separated into five

(5) zones with zones 1 and 2 being office and conference spaces, zone 3 being an equipment storage space, and zones 4 and 5 used for workshop space. Zone 4 has a footprint of 697 square feet and zone 5 has a footprint of 1,325 square feet. Overall, zones 4 and 5 constitute 36% of the building floor area.

Renovations to zones 1 and 2 have been completed and these areas are heated by two hot air propane furnaces which were installed in the spring of 2022. There is no desire to replace or disturb the propane furnaces in zones 1 and 2 as of now. Fenestration on this building includes five (5) overhead garage doors which are 9’ x 11’ in area with window glazing assumed to be single pane and 24” x 7” in area, and three single man doors and one set of double doors, all of which were assumed to be 3’ x 7’ in area with 18” x 30” single pane glass.

Cypress Branch NRMA 6/3/2022 Memorandum

WERC Wood Education and Resource Center Page 2 of 8

Due to the fact that zones 1 and 2 have both been recently renovated and equipped with brand new propane furnaces, MD DNR has expressed interest in installing a wood energy system to only serve the heating loads of zones 4 and 5. MD DNR would like to keep the middle zone 3 unheated and house the wood energy system and fuel storage within zones 3, 4, or 5.

3.0 ENERGY USAGE

3.1 EXISTING ENERGY USAGE AND COST

The workshop building was originally an old farm office with some hanging propane heaters. However, there is no way to get historical fuel usage, and neither would it be relevant since significant amounts of insulation are being added. Similarly, since the propane furnaces serving zones 1 and 2 were installed so recently, it is difficult to make accurate estimates of heat load using propane usage and cost without a full year of delivery data.

3.2 BIOMASS AVAILABILITY AND PRICE

Modern biomass combustion systems can efficiently and cleanly utilize a variety of fuels with a wide range of moisture content. The biomass system considered in this analysis would utilize wood pellets delivered from Kingdom BioFuel located in Peach Bottom, PA, approximately 62 miles northwest of the Cypress Branch NRMA. Pellets would be delivered in the form of bulk deliveries from a truck that are blown into the pellet storage container. Table 1 compares the cost of delivered heat for wood, fossil fuels, and electricity.

Table 1 - Fuel Pricing and Cost of Delivered Heat

Fuel/Technology, Unit Cost/Unit Heating Value (mmBtu/Unit)

Assumed Seasonal Efficiency

System Output (mmBtu/Unit)

Cost of Delivered Heat ($/mmBtu)

Hardwood Pellets, Tons3 $364 16.4 80% 13.1 $27.74 Cordwood, Cords3 $265 24.4 70% 17.1 $15.52 Electric Resistance, kWh1 $0.14 0.003412 100% 0.003412 $41.03 Propane, Gallons2 $1.76 0.091333 90% 0.0822001 $21.40

Notes: 1) Cost/unit for electric resistance based on Choptank Electric Cooperative Rate Schedule C and May 1, 2022 power cost adjustment.

2) Cost/unit for propane is an average of weekly wholesale prices, plus $0.25, on the East Coast from March 2021 to March 2022.

3) Cost/unit for pellets and cordwood obtained from Kingdom BioFuel.

Alternate pellet vendors include Energex located in Mifflintown, PA, and O’Malley Lumber in Baltimore.

Energex provides bulk loadout services at their mill, and could fill a bulk truck for transport to Cypress Branch, although due to the 162 mile distance the overall cost per ton for pellets would be higher than Kingdom Biofuel. O’Malley produces bagged pellets, and has distributors located on the eastern shore that could provide delivery and placement of palletized pellets. One ton of pellets takes up one pallet.

4.0 HEAT DEMAND

A heating demand model was developed for the Cypress Branch NRMA workshop building. The heat load of the building was calculated using a heat loss analysis that was comparable to the improvements that MD DNR plans to implement upon renovation of the building. Assumptions are provided below:

WERC Wood Education and Resource Center Page 3 of 8

Workshop Building: Renovations would install new R-11 rigid insulation on the building’s exterior walls and R-30 blown-in insulation for the building’s roof/ceiling. For the purposes of this analysis, roof insulation was estimated to an R-38 insulation value to obtain thermal properties of the facility. Garage doors (4) estimated at 9’ x 11’ in area with fenestration consisting of four single pane windows for each door at 24” x 7” in area. Man doors estimated to be 3’ wide and 7’ tall with 18” x 30” single pane glass.

Weather data of average daily temperatures were obtained from Tuckahoe State Park, approximately 30 miles south of Cypress Branch NRMA. Daily temperatures are used to calculate the heating degree day (HDD) for each day of the year. Figure 1 presents the modeled thermal demand for the workshop building against the average daily ambient temperature across the year.

Figure 1 - Daily Average Building Heat Demand

Note: The values shown are average daily demands. During a 24-hour period, the hourly demand is expected to fluctuate both above and below the values shown.

Figure 2 shows the heating demand model as a load duration curve (LDC). The demand curve shown below represents the total heat demand of the building analyzed here to show the load that could be served by a biomass heating system. The LDC is created by arranging average daily loads from a single year from highest to lowest and is a representation depicting the amount of time the facility would expect loads at or above and below a certain level.

Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

O ut do or

A ir

Te m p (F

H ea t D em an d

(M

BH

Entire Building Zones 4 & 5 Temp (°F)

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Figure 2 – Workshop Building Average Daily Load Duration Curve

Note: The values shown are daily average demands. During a 24-hour period, the hourly demand is expected to fluctuate above and below the values shown.

5.0 BIOMASS OPTIONS

A system option which would utilize wood pellets to serve space heating demands at the Cypress Branch NRMA workshop building has been evaluated in this analysis. The equipment and load coverage considerations are described in this section.

This project would install a 50,000 Btu/hr pellet boiler coupled with thermal storage and would serve the heating loads of zones 4 and 5 in the workshop building. Considering the capacity of the evaluated boiler, thermal storage would be sized at 119 gallons. The boiler and thermal storage would be located in zone 5, while the pellet storage would be located in zone 3. These locations have been deemed suitable in size based on measurements and discussions with staff. A conceptual layout and schematic are provided in Appendices A.1 and A.2.

Regardless of where the final installation location is selected, the boiler would provide heat to the thermal storage tank, which would service heating demands for zones 4 and 5. The project would include the relevant distribution equipment and piping, as well as hydronic terminal heat distribution equipment.

Terminal heating equipment will be exclusively suspended fan coil unit heaters. The heated water produced from the boiler, thermal storage, and heat exchanger will be distributed to each zone’s hydronic heating equipment which will operate on thermostats. It is assumed that zones 4 and 5 will have the ability for independent thermostatic control. This system option could provide 100% coverage of the thermal load for the two zones in the workshop. This coverage is illustrated in Figure 3.

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

1 13 25 37 49 61 73 85 97 10

H ea t L oa d (B tu /h r)

Days of Year

Entire Building

Zones 4 & 5

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Figure 3 – Zones 4 & 5 Biomass Heating Load Coverage Modeled For 2018-2019 Heating Season

Note: The values shown are daily average demands. During a 24-hour period, the hourly demand is expected to fluctuate above and below the values shown.

The wood pellet system will accept bulk delivery of wood pellets by pneumatic blower truck. It is important to note that the only vendor with this truck is Kingdom Biofuel. For this analysis, pellet storage has been sized at 7.6’ x 7.6’ x 6’ in volume and can hold about 5 tons of pellets. With an estimated annual usage of 3.7 tons of pellets, the pellet storage would need to be refilled once per year. The pellet storage system includes a pneumatic filling pipe and a vacuum conveyance system which feeds pellets to the boiler as needed. This way, staff never need to handle the fuel.

If indoor space is at a premium, an alternative is to locate the pellet storage outside, either in the form of a small silo or a wooden shed. This would be at an increased capital cost compared to the indoor storage, but would provide additional flexibility in that the outdoor storage could be filled using a generic grain auger truck, which could bring pellets from other pellet plants that offer bulk loadout.

If use of bagged pellets is desired, bins are available which are smaller than typical bulk storage bins, which hold about half a ton of pellets. Staff would manually pour bags of pellets into this bin once a week, and the pellets would then be automatically conveyed to the boiler as needed.

In order to protect the boiler and hydronic system in the case of downtime for maintenance or running out of pellets, consideration should be given to installing a basic propane wall-mounted heater in Zone 5.

6.0 CAPITAL AND OPERATING COSTS

Estimated capital cost for this biomass system is approximately $50,000. A capital cost breakdown is provided in Appendix A.3. Table 2 presents the modeled annual fuel usage and cost for propane vs. wood pellets.

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1 13 25 37 49 61 73 85 97 10

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A ve ra ge

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Zones 4 & 5 Heat Load

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Table 2 – Fuel Usage and Economics

Baseline Propane System Biomass System First Year SavingsPropane Usage

(gal) Propane

Cost Wood Pellet Usage (tons)

Wood Pellet Cost

624 $1,098 3.7 $1,360 ($262)

The proposed pellet system has the potential to generate about 37 pounds of ash per year. Figure 4 shows how an ash bin from a typical small commercial pellet boiler is handled. Ash should typically be emptied every 1-2 weeks, and when cool can be disposed of with other municipal waste. Wood ash can also be used as a soil amendment, and has properties similar to lime.

Figure 4 – Emptying the Ash Bin of a Typical Small Commercial Pellet Boiler

7.0 GREENHOUSE GAS EMISSIONS

By avoiding the use of propane for heating zones 4 and 5, installation of a biomass boiler system would result in the reduction of the Cypress Branch NRMA workshop building’s annual net CO2 equivalent (CO2e) reported Scope 1 emissions, as shown in Table 3. Although combustion of wood releases CO2, the use of wood fuel ultimately provides a net reduction in GHG emissions compared to fossil fuel if the wood fuel is sourced sustainably. Sustainable wood fuel is often sourced from waste byproducts of sawmill operations. A key criterion of whether a wood fuel is sustainable or not is whether its use is a driving factor in conversion of forest to non-forest use. Increased demand for forest products, whether that be for lumber or fuel, will provide value to landowners to help to ensure that forest land stays as forest land, rather than being converted to a non-forest use. As long as land remains as forest, and is managed by professional foresters, it can provide a sustainable low-carbon energy source.

The accounting in this memorandum directly follows that used by the voluntary carbon markets for the sale of carbon credits and reporting of Scope 1, Scope 2, and Scope 3 GHG emissions. Please see the Climate Registry for details. Factors for CO2e values presented in this memorandum are obtained from the Climate Registry and include CO2, as well as CH4 and N2O adjusted for their 100-year global warming potentials relative to CO2.

WERC Wood Education and Resource Center Page 7 of 8

The WERC team modeled the GHG performance based on the assumption that a propane furnace would be alternatively used to provide heat demands to zones 4 and 5, similar to zones 1 and 2 currently.

Table 3 - Annual Greenhouse Gas Emissions Summary for Heating Zones 4 & 5

Baseline Propane System Proposed Biomass System Net Reduction in Scope 1 & 2

CO2

Equivalent Emissions

(tonnes/yr)

Percent Reduction in Scope 1 & 2

CO2

Equivalent

Emissions (%)

Scope 1 Fossil Fuel CO2 Equivalent

Emissions (tonnes/yr)

Scope 2 Electric CO2 Equivalent

Emissions (tonnes/yr)

Scope 1 Biomass CO2

Equivalent Emissions

(tonnes/yr)

Scope 1 Fossil Fuel CO2

Equivalent Emissions

(tonnes/yr)

3.5 0 0.08 0 3.4 98%

Notes: 1) 1 tonne (metric tonne) is equal to 1,000 kg or 2,205 lb. Scope 1 emissions listed include only CH4 and N2O expressed as CO2 equivalent, per The Climate Registry guidelines.

2) GHG calculation assumptions can be found in Table 5.

8.0 CONCLUSIONS AND RECOMMENDATIONS

This memorandum analyzes a biomass heating system option which would provide renewably fueled heat to zones 4 and 5 in the workshop building at the Cypress Branch NRMA.

Wood Pellet Boiler: A 50,000 Btu/hr wood pellet boiler coupled with 119 gallons of thermal storage which would utilize a hydronic heating distribution system to serve heating loads of zones 4 and 5. This project also includes installation of an indoor cloth bin-type pellet storage container sized at 5 tons of capacity, as well as the terminal heat distribution equipment which includes suspended hydronic unit heaters. This system would cost about $50,000 including installation.

Fuel costs for this system would be $262 more per year compared to using propane. This system would offset potential consumption of 624 gallons of propane for heating zones 4 and 5 in the workshop building.

The installation of a biomass heating system presents Cypress Branch NRMA with the opportunity to reduce energy costs, fossil fuel consumption, and net greenhouse gas emissions. Benefits of using a wood pellet biomass system at the workshop site include:

Creating markets for forest residues to enhance opportunities for forest management activities to reduce pests and disease, prevent fires, and manage for ecological diversity, soil health, and water quality.

Avoidance of net greenhouse gas emissions of 3.4 metric tonnes annually.

Support of the local economy through $1,360 per year for locally sourced, renewable biomass fuel.

Should the Cypress Branch NRMA be interested in moving forward with a biomass option, WERC can provide additional technical assistance in an advisory capacity. Such assistance can include providing vendor lists for relevant biomass equipment, review of proposals from biomass vendors and contractors, and review of design drawings and schematics.

WERC Wood Education and Resource Center Page 8 of 8

9.0 ASSUMPTIONS

Table 4 - Calculation Assumptions

Assumption Value Units Source Workshop HDD Setpoint 65 °F WERC Assumption Workshop Setpoint 70 °F WERC Assumption Propane Furnace Seasonal Efficiency 90% % WERC Assumption Propane Higher Heating Value 91,333 Btu/gal WERC Assumption Pellet Boiler Seasonal Efficiency 80% % WERC Assumption Wood Pellet Higher Heating Value 16.4 mmbtu/ton WERC Assumption Electric Resistance Heating Value 0.003412 mmBtu/kWh WERC Assumption

Table 5 - GHG Emissions Assumptions

Assumption Value Unit Source CO2 emitted during combustion of Wood 93.8 kg/mmBtu EPA Emissions Factors 2021 CH4 emitted during combustion of Wood 0.0072 kg/mmBtu EPA Emissions Factors 2021 N2O emitted during combustion of Wood 0.0036 kg/mmBtu EPA Emissions Factors 2021 CO2 emitted during combustion of Propane 61.46 kg/mmBtu EPA Emissions Factors 2021 CH4 emitted during combustion of Propane 0.003 kg/mmBtu EPA Emissions Factors 2021 N2O emitted during combustion of Propane 0.0006 kg/mmBtu EPA Emissions Factors 2021 CO2 emitted due to use of Electricity (includes line losses) 0.312 kg/kWh EPA eGRID 2020, grid RFCE CH4 emitted due to use of Electricity (includes line losses) 0.000021 kg/kWh EPA eGRID 2020, grid RFCE N2O emitted due to use of Electricity (includes line losses) 0.0000032 kg/kWh EPA eGRID 2020, grid RFCE Electric Line Losses 5.30% percent EPA eGRID 2020 CH4 fossil origin 100-year Global Warming Potential 29.8 * CO2 IPCC AR6 CH4 non fossil origin 100-year Global Warming Potential 27.2 * CO2 IPCC AR6 N2O 100-year Global Warming Potential 273 * CO2 IPCC AR6

10.0 APPENDICES

A.1 – Conceptual Layout Drawing A.2 – Conceptual Hydronic Schematic A.3 – Capital Cost Estimate

5 Ton Indoor Pellet Storage

50,000 Btu/hr Pellet Boiler

119 Gal. Thermal Storage Tank

Hydronic Unit Heater

Zone 3 Zone 4 Zone 5

Hydronic Unit Heater

Hydronic Unit Heater Vacuum Line for Automatic

Pellet Conveyance

Pellet Delivery Connection

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Notes:

1. This is a conceptual drawing for the purposes of showing biomass system options.

2. Final design and layout will change based on equipment selected, designer, and site conditions.

Notes:

1. System is shown as using a non-ASME boiler with a vent tank. If an ASME boiler is selected, the schematic will be different because the vent tank and heat exchanger will not be needed.

2. This drawing is a conceptual layout for the purposes of showing biomass system options.

3. Final design and layout will change based on equipment selected, designer, and site conditions.

4. Not all hydronic components required for system are shown.

VFD

T Variable Frequency Drive

Temperature Transmitter

Pump

Three Way Mixing Valve

Legend

Pellet Boiler Hydronic Schematic

Boiler Protection Valve to ensure return water temperature > 140°F

119 Gallon Thermal

Storage Tank

T1 V1

T3

P3

VFD

Heat Exchanger separating open boiler system from pressurized distribution system

50,000 Btu/hr Pellet Boiler

P1

Vent Tank Elevation 4ft above highest point in open loop

Vent

To Drain

P2

VFD

Control Valve

Zone 4

Sequence of Operations:

1. The pellet boiler will supply hot water to the thermal storage tank at 160°F.

T1 controls V1 which allows supply water from the boiler to bypass the thermal storage in order to maintain a return water temperature of at least 140°F to prevent flue gas condensation. This is mainly a concern during boiler startup and at times of heavy load.

2. When the boiler is operating, P3 supplies hot water to Zones 4 & 5. P3 operates on a proportional differential pressure control scheme.

3. The temperature of water delivered to the Zones 4 & 5 is controlled by varying the speed of P2 in order to maintain the temperature setpoint at T3.

It is recommended to design the radiator system to utilize water temperatures of 120°F or lower in order to optimze the performance of the pellet storage and ensure that the system can be easily adapted to other low carbon technologies in the future.

4. Zone valves at each heat emitter are controlled by thermostats. A minimum flow bypass should be provided at the end of the loop for the case where no thermostats are calling for heat.

T2

Hydronic Unit Heater

Zone 5

Hydronic Unit Heater

Hydronic Unit Heater

Bypass

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Appendix A Cypress Branch NRMA Millington, MD

Line Item Cost 50,000 Btu/hr Pellet Boiler 13,300$ 119 Gallon Thermal Storage Tank 3,000$ Cloth Bin-Type Pellet Storage Container (91" x 91"x 72") 3,700$ Hydronic Distribution Equipment (Pumps, Heat Exchanger, Piping)4 2,900$ Hydronic Terminal Heating Equipment (Unit Heaters)4 2,300$ Mechanical and Electrical Installation 10,000$ Sub-Total 35,000$

Profit and Overhead 20% 7,000$ Sub-Total 42,000$

Contingency 15% 6,000$ Total General Contract 48,000$

Total Project Cost Line Item Cost

Project Sub-Total (General Contract) 48,000$ Professional Services 2 7% 3,000$

Total Project Cost1,3 51,000$

Notes:

1 - Assumes project is managed by owner.

2 - Professional Services includes engineering, permitting, legal, and project management.

3 - Estimate is based on vendor quotes and equipment pricing through historical cost indexes.

4 - Not all hydronic distribution parts and equipment included.

Wood Pellet Heating System

General Contract

WERC Wood Education and Resource Center A.3

Wood Energy Technical Assistance Team

Eastern Region WERC Wood Energy Technical Assistance Team

For More Information or To Obtain Technical Assistance on Your Project Contact:

US Forest Service -WERC Wood Energy Technical Assistance Team 180 Canfield St.

Morgantown, WV 26501

Lew R. McCreery, Woody Biomass Coordinator lmccreery@fs.fed.us 304-285-1538

WERC Wood Energy Technical Assistance Team:

https://www.fs.usda.gov/sites/default/files/Wood-Energy-National-Tech-Team.pdf

The information contained herein creates no warranty either express or implied. The USDA Forest Service, its officers, employees, and project partners assume no liability for its contents or use thereof. Use of this information is at the sole discretion of the user.

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