HomeMy WebLinkAboutRuby Biomass Pre Feasibility Dalson Energy 2012-BIO1
Biomass Energy Native Village of Ruby
Dalson Energy Inc.
308 G St. Ste 303
Anchorage, Alaska 99501
907-277-7900
8/25/2012
Preliminary Feasibility Assessment
This preliminary feasibility assessment considers the
potential for heating community buildings in Ruby with
woody biomass from regional forests and river logs.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 2
Table of Contents
Project Summary ........................................................................................................................................ 3
Summary of Findings ................................................................................................................................ 4
Wood fuel supply in Ruby ........................................................................................................................ 5
Biomass Energy Operations and Maintenance ............................................................................................. 6
Biomass Harvest Plan ................................................................................................................................ 6
Operations Plan......................................................................................................................................... 7
Community Facilities Information .......................................................................................................... 8
Ruby School ............................................................................................................................................... 8
Recommended technology and fuel requirements ............................................................................... 9
Initial investment .................................................................................................................................... 10
Financial Analysis .................................................................................................................................... 12
Conclusion ................................................................................................................................................ 17
Supplement: Community Wood Heating Basics ....................................................................................... 19
Wood fuel as a heating option ............................................................................................................... 19
The nature of wood fuels ........................................................................................................................ 19
The basics of wood-fueled heating ........................................................................................................ 20
Available wood heating technology ...................................................................................................... 24
Cordwood Boilers ................................................................................................................................ 24
Bulk Fuel Boilers .................................................................................................................................. 24
District heat loops ................................................................................................................................ 25
Figure 1: Land Ownership Surrounding Ruby, AK. ........................................................................................ 5
Figure 2: TCC Timber Inventory, 1990. ......................................................................................................... 6
Figure 3: Illustration of Unmanaged Wood Harvesting Efforts .................................................................... 6
Figure 4: Illustration of Planned Wood Harvest by Harvest Area and Time Period. .................................... 7
Figure 5: Ruby School Boilers ....................................................................................................................... 7
Figure 6: Cordwood ..................................................................................................................................... 19
Figure 7: Wood briquettes, as a substitute for cordwood. Cross sections of these briquettes make
“wafers” which can be automatically handled in biomass boiler systems. ................................................ 19
Figure 8: Ground wood chips used for mulch. ............................................................................................ 19
Figure 9: Wood pellets ................................................................................................................................ 19
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 3
Project Summary
Interior Regional Housing Authority (IRHA) and Tanana Chiefs Conference (TCC)
contracted Dalson Energy to do a Pre-Feasibility Study (Pre-FS) for biomass heating of
community buildings in the Native Village of Ruby.
Dalson Energy biomass specialists Thomas Deerfield and Wynne Auld visited the
community on June 16, 2012 for the initial assessment. Deerfield and Auld made their
assessment based on available data, interviews with local stakeholders and authorities,
observations, and research and review of previous studies done in Ruby.
It was noted that there are several other studies and reports that address various
aspects of biomass energy in Ruby, including Forestry Resource assessments done by
TCC Forester Will Putman and DNR Division of Forestry. Clare Doig of Forest and
Land Management Inc. is also completing a forest management plan for the regional
corporation, Gana’a’Yoo. These previous studies are the foundation for further
evaluation of institutional heating with woody biomass in Ruby, as exercised in this
prefeasibility assessment.
This report was prepared by Thomas Deerfield, Wynne Auld, Louise Deerfield, and
Clare Doig.
Contact and interviews with the following individuals in Ruby assisted in some of the
information gathering. Their contact information is as follows:
City - City of Ruby
P.O. Box 90
Ruby, AK 99768
Phone 907-468-4401
Fax 907-468-4443
Tribe-- Ruby Village, federally-recognized
P.O. Box 68210
Ruby, AK 99768
Phone 907-468-4479
Fax 907-468-4474
E-mail rubynativecouncil@hotmail.com
Ed Sartan, project contact
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 4
School—Ruby School
Don Honea Jr, Maintenance Manager
Summary of Findings
Currently, the opportunities for wood heating with commercial-scale biomass heating
systems in the Community of Ruby appear to be financially challenged by low heat
loads and relatively long payback terms. Small residential-scale heating systems
(woodstoves, etc) are always a viable option, but are not in the scope of this study.
The two identified projects are (1) the School and (2) the Washateria. The Washateria is
completely heated by waste heat, so it was not evaluated for wood heat. The School has
a relatively low consumption of fuel oil, so under the current assumptions the capital
cost of investment cannot be recouped. The School was evaluated for a HELE (high
efficiency, low emission) cordwood boiler system.
Boiler
Size
(BTU/hr)
Capital
Cost
Annual
Operations
Cost, Yr. 1
Annual
Cash
Savings,
Yr. 1
Simple
Payback,
Yrs.
NPV
Net
Benefit
B/C
School 350,000 $279,900 $30,765 $4,593 60.9 ($151,805) 0.44
The next step is full report findings presentation to IRHA and TCC. As service
providers to the Village of Ruby, they will determine the next steps forward.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 5
Wood fuel supply in Ruby
In 1987 Tanana Chiefs Conference completed a timber inventory of the ANCSA Native
Village lands around Ruby. Much of this material could be considered woody biomass
suitable for wood fueled heating systems. Doyon, Limited, the regional corporation, is
the other major landowner in the region, as indicated by Figure 1: Land Ownership
Surrounding Ruby, AK.
While these inventory figures indicate a substantial timber resource, sites supporting
tree growth are widely distributed and may be difficult to access because of the area
characteristics and the lack of existing roads. The Village is located along a major river
system with expansive low elevation wetlands, resulting in widely distributed higher
elevation sites that support tree growth. These factors impact the economics of fuel
availability, which in turn impacts the size and fuel demand for a wood fueled heating
system in the community. Additional considerations include 1) the landowner’s
contractual agreement for harvest and compensation for the resource, 2) public
acceptance of larger scale timber harvest than has been experienced in recent history,
and 3) total project (from timber harvest to operation of the heating system) economic
feasibility.
Figure 1: Land Ownership Surrounding Ruby, AK.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 6
Figure 2: TCC Timber Inventory, 1987.
The community of Ruby also practices river logging and reportedly uses the river
extensively for transporting wood via rafts from areas up and down river.
Dependability and volume of river-caught logs have not been documented.
Biomass Energy Operations and Maintenance
Biomass Harvest Plan
Wood cutting is a subsistence activity in almost all interior Villages adjacent to forest
land. This subsistence resource must be carefully managed or biomass energy projects
may be detrimental to the Community.
If biomass harvests are unmanaged, the natural tendency is to harvest the most
accessible wood supply first, as illustrated below. The effect is increased scarcity and
rising harvest cost, and, consequently, biomass fuel costs, for both the project and
household woodcutters. This puts community members’ energy security and the
project’s success at risk.
Ruby (1987)Acres Cubic Feet Board Feet
(thousands)
Saw Timber Types: (10.5"+ d.b.h.)
White Spruce 2,157 5,755,000 15,804
Black Spruce 319 286,000 385
Hardwood 14,541 33,637,000 63,671
Mixed White Spruce/Hardwood 7,875 19,483,000 48,685
Mixed White Spruce/Cottonwood 333 584,000 1,675
Subtotal 25,225 59,745,000 130,220
Figure 3: Illustration of Unmanaged Wood Harvesting Efforts
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 7
The project’s success depends on a well-developed and executed Harvest Plan. The
Harvest Plan accounts for the biomass harvests over the project lifetime, at least 20
years. It may also designate areas for Personal Use (household wood cutting). The
Harvest Plan also describes how who is responsible for executing the Harvest Plan, and
how access will be managed. Please see figure below.
Because the project’s success is critically dependent on a Biomass Harvest Plan, the
Consultant strongly recommends developing this Plan prior to project development.
Operations Plan
In many Villages biomass boiler
projects will depend on collaboration
among a variety of entities, including
contract wood cutters, forest
landowners, the boiler technician,
building owners and operators, and
various governmental entities.
A plan for collecting biomass, paying
wood suppliers, allocating costs
among heat users, and operating and
maintaining the boiler and heat
distribution system is crucial to the
project’s success. Persons
responsible for each task must be identified.
Figure 5: Ruby School Boilers
Figure 4: Illustration of Planned Wood Harvest by Harvest Area and Time Period.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 8
Because the project’s success is critically dependent on an Operations Plan, the
Consultant strongly recommends developing this Plan prior to project development.
Community Facilities Information
Only one community buildings in Ruby was evaluated for biomass heating -- the Ruby
School. Other buildings considered include the City and Tribal Offices, and the
Washateria. The City and Tribal Offices are located in a flood zone and have very low
fuel oil consumption, and the Washateria gets all of its heat from a waste heat system.
Therefore, these buildings were not evaluated further.
Ruby School
The Ruby School uses one (1) 404 MBH fuel oil boiler, and retains a second boiler for
back up. The School also produces hot water for teacher housing, but the houses have
their own Toyostove for space heating. All appliances in the school are hydronic. The
system uses 6,000 – 7,000 gallons per year of oil.
The School maintenance technician is Don Honea Jr, who has maintained the School
since 1986. He works part-time. Don stated he is “all for” a wood energy system. Don
has maintained the School since 1986. Ed Sartan and the Principal, Ann Titho, would
also champion the project.
It is also worth noting that a community member, Gary Brown, has undertaken biomass
boiler training with Rex Goulsby of Lars Construction and also suggested he would
champion a project.
Building Name School
Annual Gallons (Fuel Oil #1) 6,000 – 7,000 gal/ yr
Building Usage During the School year
Heat Transfer Mechanism Hydronic
Maximum cords to heat the building 49
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 9
Recommended technology and fuel requirements
For the School, a pre-fabricated, modular, containerized HELE (high efficiency, low
emissions) cordwood boiler is recommended. These types of systems are produced by
GARN, TARM USA and others. The GarnPac has about 350,000 BTU output and is
currently being employed in Thorne Bay. This type of system design is recommended
because it has demonstrated reliability, uses an accessible fuel, cordwood, and it is a
modular unit and therefore has lower installation cost and financing advantages. The
Consultant recommends adding providers of these units, Garn/Dectra, TARM,
Greenwood, and similar system manufacturers, to the list of potential equipment
providers.
Other communities operating HELE cordwood boilers of a similar size, such as Dot
Lake and Ionia, report 2 cordwood stokings per day and 0.125 – 0.5 FTE 1 (Full-time
equivalent employee) per boiler.
Initial project development costs for a wood heating system costs may include:
Capital costs: boiler, hydronic pipe and other hardware, wood storage shelter,
fuel-handling equipment, shipping costs.
Engineering: storage design, plumbing integration, fuel-handling
infrastructure.2
Permitting: no permits required. In lieu of permits, all regulations must be met.
Installation: Site work, installation, and integration into existing system.
Fuel storage: storage building, firewood chutes, or preparation of existing
storage room.
System building: (if required).
Ongoing operational costs may include:
Financing: Principal and interest payments from project debt, or profits from
project equity investment. In Village projects, financing costs likely do not apply.
Wood fuel purchases.
Amortization costs: capital equipment and other infrastructure.3 When projects
are grant financed, amortization does not apply.
1 Nicholls, David. 2009. Wood energy in Alaska—case study evaluations of selected facilities. Gen. Tech. Rep. PNW-
GTR-793. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 33 p.
2 Not all projects require engineering design.
3 Cash and accrual basis are two different accounting methods for project investment. Accrual accounting
amortizes project investment over the project lifetime (“lifecycle costs”). This method results in monies to reinvest
in new equipment at the end of its lifetime. Cash basis is simply on the dollars spent to operate, maintain, and
finance the project.
4 Fossil fuel purchases and labor.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 10
Operations and Maintenance (O&M) labor.
Initial investment
The School has an estimated Capitalization Cost of $279,700.
See charts below for cost estimates and sources. Full feasibility analysis and/or bids
would provide more detailed numbers.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 11
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 12
Financial Analysis
Project Description
Community
Nearest Fuel Community
Region
RE Technology
Project ID
Applicant Name
Project Title
Category
Results
NPV Benefits $119,948
NPV Capital Costs $271,753
B/C Ratio 0.44
NPV Net Benefit ($151,805)
Performance Unit Value
Displaced Electricity kWh per year -
Displaced Electricity total lifetime kWh -
Displaced Petroleum Fuel gallons per year 6,003
Displaced Petroleum Fuel total lifetime gallons 162,500
Displaced Natural Gas mmBtu per year -
Displaced Natural Gas total lifetime mmBtu -
Avoided CO2 tonnes per year 61
Avoided CO2 total lifetime tonnes 1,649
Proposed System Unit Value
Capital Costs $279,905$
Project Start year 2013
Project Life years 25
Displaced Electric kWh per year -
Displaced Heat gallons displaced per year 5,850
Displaced Transportation gallons displaced per year 0.00
Renewable Generation O&$ per BTU
Electric Capacity kW 0
Electric Capacity Factor %0
Heating Capacity Btu/hr.350,000
Heating Capacity Factor %86
Base System Unit Value
Diesel Generator O&M $ per kWh 0.033$
Diesel Generation Efficien kWh per gallon
Ruby
Rural
Woody biomass heat
Village of Ruby
School
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 13
Annual Savings (Costs)Units 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Entered Value Project Capital Cost $ per year 279,905$ -$ -$ -$ -$ -$ -$ -$ -$ -$ -$
Electric Savings (Costs)$ per year $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Heating Saving (Costs)$ per year $4,222 $4,593 $4,845 $5,196 $5,671 $6,113 $6,527 $6,899 $7,232 $7,473 $7,714
Transportation Savings (Costs)$ per year $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Total Savings (Costs)$ per year $4,222 $4,593 $4,845 $5,196 $5,671 $6,113 $6,527 $6,899 $7,232 $7,473 $7,714
Net Benefit $ per year ($275,684)$4,593 $4,845 $5,196 $5,671 $6,113 $6,527 $6,899 $7,232 $7,473 $7,714
Annual Savings (Costs)Units 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034
Entered Value Project Capital Cost $ per year -$ -$ -$ -$ -$ -$ -$ -$ -$ -$ -$
Electric Savings (Costs)$ per year $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Heating Saving (Costs)$ per year $7,920 $8,094 $8,235 $8,316 $8,333 $8,312 $8,244 $8,115 $7,932 $7,753 $7,554
Transportation Savings (Costs)$ per year $0 $0 $0 $0 $0 $0 $0 $0 $0 $0 $0
Total Savings (Costs)$ per year $7,920 $8,094 $8,235 $8,316 $8,333 $8,312 $8,244 $8,115 $7,932 $7,753 $7,554
Net Benefit $ per year $7,920 $8,094 $8,235 $8,316 $8,333 $8,312 $8,244 $8,115 $7,932 $7,753 $7,554
Annual Savings (Costs)Units 2035 2036 2037 PV
Entered Value Project Capital Cost $ per year -$ -$ -$ $271,753
Electric Savings (Costs)$ per year $0 $0 $0 $0
Heating Saving (Costs)$ per year $7,381 $7,441 $7,504 $119,948
Transportation Savings (Costs)$ per year $0 $0 $0 $0
Total Savings (Costs)$ per year $7,381 $7,441 $7,504 $119,948
Net Benefit $ per year $7,381 $7,441 $7,504 ($151,805)
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 14
Heating Units 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Renewable Heat gallons displa 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850
Entered Value Renewable Heat Scheduled Rep$ per year 300$ 303$ 306$ 309$ 312$ 315$ 318$ 322$ 325$ 328$ 331$
Entered Value Renewable Heat O&M $ per year 12,361$ 12,485$ 12,610$ 12,736$ 12,863$ 12,992$ 13,122$ 13,253$ 13,385$ 13,519$ 13,654$
Entered Value Renewable Fuel Use Quantity (cords 49 49 49 49 49 49 49 49 49 49 49
Entered Value Renewable Fuel Cost $ per unit $300.00 $303 $306 $309 $312 $315 $318 $322 $325 $328 $331
Total Renewable Fuel Cost $ per year 14,700$ 14,847$ 14,995$ 15,145$ 15,297$ 15,450$ 15,604$ 15,760$ 15,918$ 16,077$ 16,238$
Remaining Fuel Oil (supplemen gallons rema 650 650 650 650 650 650 650 650 650 650 650
Total Fuel Cost (supplement)$ per year 3,404$ 3,474$ 3,532$ 3,601$ 3,684$ 3,764$ 3,840$ 3,913$ 3,981$ 4,040$ 4,099$
Proposed Heat Cost $ per year 30,765$ 31,109$ 31,443$ 31,791$ 32,156$ 32,520$ 32,885$ 33,248$ 33,609$ 33,964$ 34,322$
Fuel Use gallons per y 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500
Fuel Cost $ per gallon $5.24 $5.35 $5.43 $5.54 $5.67 $5.79 $5.91 $6.02 $6.13 $6.22 $6.31
Entered Value Fuel Scheduled Repairs $ per year 200$ 202$ 204$ 206$ 208$ 210$ 212$ 214$ 217$ 219$ 221$
Entered Value Fuel O&M $ per year 750$ 758$ 765$ 773$ 780$ 788$ 796$ 804$ 812$ 820$ 828$
Fuel Cost $ per year 34,036$ 34,743$ 35,319$ 36,008$ 36,839$ 37,635$ 38,403$ 39,128$ 39,813$ 40,398$ 40,987$
Base Heating Cost $ per year 34,986$ 35,702$ 36,288$ 36,987$ 37,827$ 38,634$ 39,412$ 40,147$ 40,842$ 41,437$ 42,037$
Proposed
Base
Heating Units 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034
Renewable Heat gallons displa 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850 5,850
Entered Value Renewable Heat Scheduled Rep$ per year 335$ 338$ 341$ 345$ 348$ 352$ 355$ 359$ 362$ 366$ 370$
Entered Value Renewable Heat O&M $ per year 13,791$ 13,929$ 14,068$ 14,209$ 14,351$ 14,494$ 14,639$ 14,786$ 14,933$ 15,083$ 15,234$
Entered Value Renewable Fuel Use Quantity (cords 49 49 49 49 49 49 49 49 49 49 49
Entered Value Renewable Fuel Cost $ per unit $335 $338 $341 $345 $348 $352 $355 $359 $362 $366 $370
Total Renewable Fuel Cost $ per year 16,400$ 16,564$ 16,730$ 16,897$ 17,066$ 17,237$ 17,409$ 17,583$ 17,759$ 17,937$ 18,116$
Remaining Fuel Oil (supplemen gallons rema 650 650 650 650 650 650 650 650 650 650 650
Total Fuel Cost (supplement)$ per year 4,154$ 4,206$ 4,255$ 4,297$ 4,333$ 4,365$ 4,391$ 4,412$ 4,427$ 4,442$ 4,456$
Proposed Heat Cost $ per year 34,680$ 35,037$ 35,394$ 35,748$ 36,098$ 36,448$ 36,795$ 37,140$ 37,482$ 37,828$ 38,175$
Fuel Use gallons per y 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500 6,500
Fuel Cost $ per gallon $6.39 $6.47 $6.55 $6.61 $6.67 $6.71 $6.76 $6.79 $6.81 $6.83 $6.86
Entered Value Fuel Scheduled Repairs $ per year 223$ 225$ 228$ 230$ 232$ 235$ 237$ 239$ 242$ 244$ 246$
Entered Value Fuel O&M $ per year 837$ 845$ 854$ 862$ 871$ 879$ 888$ 897$ 906$ 915$ 924$
Fuel Cost $ per year 41,540$ 42,061$ 42,548$ 42,972$ 43,329$ 43,646$ 43,914$ 44,119$ 44,266$ 44,422$ 44,559$
Base Heating Cost $ per year 42,599$ 43,131$ 43,629$ 44,064$ 44,432$ 44,760$ 45,039$ 45,255$ 45,414$ 45,581$ 45,729$
Proposed
Base
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 15
Heating Units 2035 2036 2037 PV
Renewable Heat gallons displa 5,850 5,850 5,850
Entered Value Renewable Heat Scheduled Rep$ per year 373$ 377$ 381$ $5,813
Entered Value Renewable Heat O&M $ per year 15,386$ 15,540$ 15,695$ $239,497
Entered Value Renewable Fuel Use Quantity (cords 49 49 49
Entered Value Renewable Fuel Cost $ per unit $373 $377 $381
Total Renewable Fuel Cost $ per year 18,297$ 18,480$ 18,665$
Remaining Fuel Oil (supplemen gallons rema 650 650 650
Total Fuel Cost (supplement)$ per year 4,473$ 4,516$ 4,560$
Proposed Heat Cost $ per year 38,530$ 38,913$ 39,301$ $600,310
Fuel Use gallons per y 6,500 6,500 6,500
Fuel Cost $ per gallon $6.88 $6.95 $7.02 $7.08
Entered Value Fuel Scheduled Repairs $ per year 249$ 251$ 254$ $3,875
Entered Value Fuel O&M $ per year 934$ 943$ 952$ $14,531
Fuel Cost $ per year 44,728$ 45,160$ 45,599$ $701,852
Base Heating Cost $ per year 45,911$ 46,355$ 46,805$ $720,258
Proposed
Base
16
Life cycle cost analysis (LCCA) for School
Project: Cluster #1
Project No. NA
Study Period:20
Discount Rate: 3.50%
Alternative #1 (low)Alternative #2 (high)
Initial Investment Cost 242,213$ 279,905$
O&M and Repair Cost 199,703$ 196,928$
Replacement Cost 166,792$ 166,792$
Residual Value 27,772$ 55,261$
Total Life Cycle Cost 636,481$ 698,887$
GSF of Project 29,916 29,916
Initial Cost/ GSF 8.10$ 9.36$
LCC/ GSF 21.28$ 23.36$
Life Cycle Costs of Project Alternatives
Ruby School
YEAR 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Discount Rate 3.50%
Gen'l Inflation for O&M 1.50%
NPV
O&M $199,703 12,361$ 12,546$ 12,735$ 12,926$ 13,120$ 13,316$ 13,516$ 13,719$ 13,925$ 14,134$ 14,346$ 14,561$ 14,779$ 15,001$ 15,226$ 15,454$ 15,686$ 15,921$ 16,160$ 16,403$
Replacement $166,792 -$ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 224,644$
Residual $27,772 -$ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 55,261$
Discount Rate 3.50%
Gen'l Inflation for O&M 1.50%
NPV
O&M $196,928 12,361$ 12,361$ 12,546$ 12,735$ 12,926$ 13,120$ 13,316$ 13,516$ 13,719$ 13,925$ 14,134$ 14,346$ 14,561$ 14,779$ 15,001$ 15,226$ 15,454$ 15,686$ 15,921$ 16,160$
Replacement $166,792 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 224,644$
Residual $55,261 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 55,261$
Alt. 1
Alt 2
17
Conclusion
The Village of Ruby does not have significant opportunities for biomass heating at this time. For the
purposes of this project, containerized cordwood boilers were scoped as the appropriate technology.
At the present, the capital cost of this technology is too expensive to pay back under the project
assumptions. The project considered shows a negative net present value.
The community of Ruby does appear to have a substantial biomass resource that could perhaps be
use for other beneficial purposes besides community heat energy.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 18
Consultant/Authors of this report:
Dalson Energy is a Renewable Energy Consulting and Technology Research firm based in
Anchorage. Dalson staff and partners have decades of experience in construction project
management, project development consulting and renewable energy technology research. Dalson
teams with licensed engineers, architects and designers in Alaska, Canada and Lower 48.
Dalson Energy has worked with Alaska Energy Authority, Alaska Center for Energy & Power,
University of Alaska Fairbanks, Washington State CTED (Community Trade & Economic
Development) and California Energy Commission on biomass energy technology research.
Dalson’s President, Thomas Deerfield, has been involved in biomass energy RD&D since 2001,
winning grants and managing projects with NREL (National Renewable Energy Labs), USFS (US
Forest Service), and CEC (California Energy Commission).
Thomas managed the field-testing of biomass CHP systems, including the first grid-connected
biomass gasification CHP system in the US. (2007). Thomas coordinated the design and creation of
the first prototype Biomass “Boiler in a Box” in Alaska, in 2010. That Garn-based system is now
deployed in Elim, in the Bering Sea region.
Thomas founded Shasta Energy Group (SEG), a 501c3 nonprofit, and managed wind energy research,
biomass energy feasibility studies, energy efficiency for buildings, and hydronic heating system
research design and development (RD&D). He also initiated a rural economic development think
tank and has engaged his writing skills to assist many other renewable energy project initiatives.
Wynne Auld is a Biomass Energy Specialist with Dalson Energy. She focuses on assessing and
developing woody biomass energy projects. Over the past few years, she has supported the business
development of integrated biomass energy campuses in Oregon and Idaho, especially related to their
energy initiatives. Her efforts have included marketing Campus biomass heating products to major
wholesalers and retail buyers, and planning and developing Campus sort yards and small-scale CHP.
Wynne also specializes in assisting commercial and municipal building managers in assessing the
feasibility of biomass heating, and implementing their projects. She works to ensure vibrant rural
communities through sustainable natural resource utilization.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 19
Supplement: Community Wood Heating Basics
Wood fuel as a heating option
When processed, handled, and combusted appropriately, wood fuels are
among the most cost-effective and reliable sources of heating fuel for
communities adjacent to forestland.
Compared to other heating energy fuels, wood fuels are characterized by
lower energy density and higher associated transportation and handling
costs. This low bulk density results in a shorter viable haul distance for
wood fuels compared to fossil fuels. However, this “limit” also creates an
advantage for local communities to utilize locally-sourced wood fuels,
while simultaneously retaining local energy dollars and exercising local
resource management.
Most Interior Villages are particularly vulnerable to high energy prices
because the region has over 13,500 heating degree days 4 (HDD) per year –
160% of Anchorage’s HDDs, or 380% of Seattle’s HDDs. For many
communities, wood-fueled heating lowers fuel costs. For example,
cordwood sourced at $250 per cord is just 25% of the cost per MMBTU as
fuel oil #1 sourced at $7 per gallon. Besides the financial savings, local
communities benefit from the multiplier effect of circulating fuel money
in the community longer, more stable energy prices, job creation, and
more active forest management.
In all the Interior Villages studied, the community’s wood supply and
demand are isolated from outside markets. Instead, the firewood market
is influenced by land ownership, existing forest management and ecological
conditions, local demand and supply, and the State of Alaska Energy
Assistance program.
The nature of wood fuels
Wood fuels are specified by moisture content, granulometry, energy density,
ash content, dirt and rocks, and fines and coarse particles. Each of these
characteristics affects the wood fuel’s handling characteristics, storage requirements, and combustion
process. Fuels are considered higher quality if they have lower moisture, ash, dirt, and rock contents;
consistent granulometry; and higher energy density.
4 Heating degree days are a metric designed to reflect the amount of energy needed to heat the
interior of a building. It is derived from measurements of outside temperature.
Figure 9: Wood pellets
Figure 8: Ground wood chips
used for mulch.
Figure 7: Wood briquettes, as a
substitute for cordwood. Cross
sections of these briquettes make
“wafers” which can be
automatically handled in biomass
boiler systems.
Figure 6: Cordwood
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 20
Many types of fuel quality can be used in wood heating projects so long as the infrastructure
specifications match the fuel content characteristics. Typically, lower quality fuel will be the lowest
cost fuel, but it will require more expensive storage, handling, and combustion infrastructure, as well
as additional maintenance.
Projects in interior Alaska must be designed around the availability of wood fuels. Some fuels can be
manufactured on site, such as cordwood, woodchips, and briquettes. The economic feasibility of
manufacturing on site can be determined by a financial assessment of the project; generally speaking,
larger projects offer more flexibility in terms of owning and operating harvesting and manufacturing
equipment, such as a wood chipper, than smaller projects.
It is unlikely that interior communities will be able to manufacture pellets, from both a financial,
operational, and fuel sourcing perspective. However, some interior communities may be able to
manufacture bricks or firelogs made from pressed wood material. These products can substitute for
cordwood in woodstoves and boilers, while reducing supply pressure on larger diameter trees than
are generally preferred for cordwood. At their simplest, brick presses are operated by hand, but
require chipped, dry fuel.
The basics of wood-fueled heating
Biomass heating systems fit into two typical categories: first, stoves and fireplaces that heat space
directly through convection and radiation by burning cordwood or pellets; second, hydronic systems
where the boiler burns cordwood, woodchips or pellets to heat liquid that is distributed to radiant
piping, radiators or heat exchangers. The heated liquid is distributed out to users, then returned to
the heat source for re-heating.
Hydronic systems are appropriate for serving individual buildings, or multiple buildings with
insulated piping called heat loops. Systems that serve multiple buildings are called district heating
loops. District heating is common in Europe, where larger boilers sometimes serve entire Villages.
Biomass boilers are dependent on the compatibility of the chosen fuel, handling system, and
combustion system. General categories for typically available biomass fuel systems follow:
Batch load solid chunk boiler
Semi-automated or fully-automated chipped or ground biomass boilers
Fully-automated densified-fuel boiler, using pellets, bricks, or pucks
The system application is typically determined by size of heat load, available wood fuels, and
available maintenance personnel. General categories for heat load and wood fuel follow:
Loads < 1 MMBTU often use cordwood or pellet boilers
Loads > 1MMBTU often use pellet or woodchip boilers
Loads > 10MMTU often use hog-fuel (mixed ground wood)
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 21
Each wood fuel type has different handling requirements and is associated with different emission
profiles. For example, industrial systems greater than 10 MMBTU often require additional particulate
and emission controls because of the combustion properties of hog-fuel.
One category of system that is particularly appropriate for remote rural communities is cordwood
boilers. Cordwood boilers are batch-loaded with seasoned cordwood. A significant advantage to
cordwood is that very little infrastructure is needed to manufacture or handle the heating fuel. At its
most basic, cordwood can be “manufactured” with a chainsaw (or handsaw) and an ax, and residents
of rural communities are often accustomed to harvesting wood to heat their homes and shops.
Harvesting in most Interior Villages is accomplished with ATV’s, river skiffs, sleds and dog teams,
and snow machines. Since cordwood systems are batch loaded by hand, they do not require
expensive automated material handling systems. Covered storage is required; such storage may be as
simple as an existing shed or a vented shipping container, rather than newly constructed storage
structures.
Challenges to cordwood include higher labor costs associated with manual loading. Some LEHE (low
efficiency, high emission) technologies such as Outdoor Wood Boilers (OWBs) have been criticized
for their high emissions and excessive wood consumption.
Cordwood systems are typically less than 1 MMBTU. However, if needed, some types of cordwood
boilers can be “cascaded,” meaning multiple boilers can meet heat demand as a single unit. However,
above a certain heat load, automated material handling and larger combustion systems become
viable.
Woodchip systems can be automated and thereby less labor intensive. However, woodchip systems
have significantly higher capital costs than both cordwood and pellet systems. Additionally, a
reliable stream of woodchips typically depends on a regionally active forest products manufacturing
base in the area, and active forest management. In most Interior communities, institutional heating
with woody biomass does not justify the purchase of log trucks, harvesting, handling, and
manufacturing equipment.
Pellet systems are the most automated systems, and have lower capital equipment costs than
woodchip systems. Lower costs are due to the smaller size of required infrastructure and simplified
handling and storage infrastructure. However, pellet fuel and other densified fuels tend to be more
expensive than other wood fuels, and require reliable access to pellet fuels.
For any system, the mass of feedstock required annually is determined by three parameters:
1) Building heat load
2) Net BTU content of the fuel
3) Efficiency of the boiler system
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 22
Building heat loads are determined by square footage, orientation and usage, as well as energy
efficiency factors such as insulation, moisture barriers and air leakage. Usage is particularly
important because it influences peak demand. For example, a community center which is used only a
few times per month for events, and otherwise kept at a storage temperature of 55 d. F, would have a
much different usage profile than a City Office which is fully occupied during the work day and
occasionally during evenings and weekends.
Building heat load analysis, including the building usage profile, is a particularly important part of
boiler right-sizing. A full feasibility analysis would conduct analyses that optimize the return on
investment (ROI) of systems. Typically, optimizing a biomass project’s ROI depends on a
supplementary heating system, such as an oil fired system, to meet peak demand and prevent short-
cycling of the biomass boiler. Full feasibility analyses may not be necessary for small projects,
especially for those employing cordwood boilers.
Biomass boiler efficiencies vary from 60% to 80%, depending on the manufacturer and the field
conditions of the equipment. The efficiency is strongly influenced by the BTU value and MC
(moisture content) of the fuel. Wood fuels with greater than 50% MC generally result in lower
efficiency systems, because some energy is used to drive off moisture from the fuel during the
combustion process. The reduction in energy output is mathematically equal; 50% MC generally
means 50% reduction in potential BTU value.
Like other combustion-based energy systems, woody biomass boilers produce emissions in the
combustion process. Compared to fossil fuels (coal, natural gas, and fuel oil), wood fuel emissions
are low in nitrogen oxides (NOx); carbon monoxide (CO, a product of incomplete combustion); sulfur
dioxide (SO2); and mercury (Hg). Because these compounds are all products of the forest and CO
would release naturally during the process of decay or wildfire, they generally do not concern
regulatory agencies. For emission control agencies, the real interest is particulate matter (PM)
emissions, which affect the air quality of human communities. Some wood systems are extremely
sophisticated, producing less than 0.06 lb/ MMBTU of PM.
Effective methods of PM control have been developed to remove most of the particles from the
exhaust air of wood combustion facilities. These include introduction of pre-heated secondary air,
highly controlled combustion, and PM collection devices.
Biomass boiler systems typically integrate a hot water storage tank, or buffer tank. The storage tank
prevents short cycling for automated boilers and improves efficiency and performance of batch-fired
systems, by allowing project buildings to draw on the boiler’s hot water long after the combustion
process. The GarnPac boiler design incorporates hot water storage into the boiler jacket itself, storing
approximately 2,200 gallons of hot water. Other boilers are typically installed with a separate hot
water storage tank.
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 23
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 24
Available wood heating technology
This section will focus generally on manufacturers of the types of technology discussed previously.
Cordwood Boilers
High Efficiency Low Emission (HELE) cordwood boilers are designed to burn cordwood fuel cleanly
and efficiently.
Cordwood used at the site will ideally be seasoned to 25% MC (moisture content) and meet the
dimensions specified by the chosen boiler. The actual amount of cordwood used would depend on
the buildings’ heat load profile, and the utilization of a fuel oil system as back up.
The following table lists three HELE cordwood boiler suppliers, all of which have units operating in
Alaska. Greenwood and TarmUSA, Inc. have a number of residential units operating in Alaska, and
several GARN boilers, manufactured by Dectra Corporation, are used in Tanana, Kasilof, Dot Lake,
Thorne Bay and other locations to heat homes, Washaterias, and Community Buildings.
HELE Cordwood Boiler Suppliers
Vendor Btu/hr ratings Supplier
Tarm 100,000 to 198,000 Tarm USA www.tarmusa.com
Greenwood 100,000 to 300,000 Greenwood www.greenwoodusa.com
GARN 250,000 to 700,000 Dectra Corp. www.dectra.net/garn
Note: These lists are representational of available systems, and are not inclusive of all options.
Bulk Fuel Boilers
The term “bulk fuel” refers to systems that utilize wood chips, pellets, pucks, or other loose
manufactured fuel. Numerous suppliers of these boilers exist. Since this report focuses on Village-
scale heating, the following chart outlines manufacturers of chip and pellet fuel boilers < 1 MMBTU.
HELE Bulk Fuel Boiler Suppliers
Vendor Btu/hr ratings Supplier
Froling 35,800 to 200,000; up to 4 can be cascaded
as a single unit at 800,000 BTU
Tarm USA
www.tarmusa.com
KOB 512,000 – 1,800,000 BTU (PYROT model) Ventek Energy Systems Inc.
peter@ventekenergy.com
Binder 34,000 BTU – 34 MMBTU BINDER USA
contact@binder-boiler.com
Note: These lists are representational of available systems, and are not inclusive
Dalson Energy Inc. – Native Village of Ruby Preliminary Feasibility Assessment 25
The following is a review of Community Facilities being considered for biomass heating. The
subsequent section will recommend a certain type of biomass heating technology, based on the
Facility information below.
District heat loops
District heat loops refers to a system for heating multiple buildings from a central power plant. The
heat is transported in a piping system to consumers in the form of hot water or steam.
These are the key factors that affect the cost of installing and operating a district heating system 5:
• Heat load density.
• Distance between buildings. Shorter distances between buildings will allow use of smaller
diameter (less expensive) pipes and lesser pumping costs.
• Permafrost. In the Interior, frozen soil could affect construction costs and project feasibility.
Aboveground insulated piping may be preferred to underground piping, such as the
cordwood system recently installed in Tanana, Alaska.
• Piping materials used. Several types of tubing are available for supply and return water. Pre-
insulated PEX tubing may be the preferred piping material for its flexibility and oxygen
barrier.
• District loop design. Water can be piped in one direction (i.e., one pipe enclosed) or two
directions (two pipes enclosed) for a given piping system. Design affects capital costs and
equality of heat distribution.
• Other considerations. Pump size, thermal load (BTUs per hour), water temperature, and
electrical use are other variables.
For the purposes of this study, the consultants have chosen to estimate the costs of district heat loops
using the RET Screen, a unique decision support tool developed with the contribution of numerous
experts from government, industry, and academia. The software, provided free-of-charge, can be
used worldwide to evaluate the energy production and savings, costs, emission reductions, financial
viability and risk for various types of Renewable-energy and Energy-efficient Technologies (RETs),
including district heat loops from biomass.
5 Nicholls, David; Miles, Tom. 2009. Cordwood energy systems for community heating in Alaska—an
overview. Gen. Tech. Rep. PNW-GTR-783. Portland, OR: U.S. Department of Agriculture, Forest
Service, Pacific Northwest Research
Station. 17 p.