HomeMy WebLinkAboutChickaloon Tribal Administration Biomass Pre-Feasability Study 07-25-2013-BIOChickaloon
Biomass
Pre-‐feasibility
Study
Submitted
to
Chickaloon
Environmental
Office
and
AWEDTG
Greg
Koontz,
ME;
Bill
Wall,
PhD
Chickaloon
Tribal
Administration
Office
July
25,
2013
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Table
of
Contents
EXECUTIVE
SUMMARY ............................................................................................................3
1.1
Acknowledgements ................................................................................................................3
1.3
Sources ...................................................................................................................................3
1.4
Scope ......................................................................................................................................4
1.5
Resource
and
Economic
Assumptions .....................................................................................4
Cost
Escalation
for
Fuels .......................................................................................................................6
Pellet
Purchase,
Delivery,
and
Storage .................................................................................................8
Pellet
Stoves,
Pellet
Boilers,
and
Solar
Heat .........................................................................................8
1.6
Summary
of
Economic
Findings...............................................................................................8
Benefit
Cost
Ratio ...............................................................................................................................12
1.7
Next
steps ............................................................................................................................13
TECHNICAL
SUMMARY..........................................................................................................14
2.1
Existing
Conditions ...............................................................................................................14
2.2
Wood
Fuels
/
Wood
Fired
Heating
Equipment:.....................................................................14
Boiler
Maintenance ............................................................................................................................16
2.3
Proposed
Configuration ........................................................................................................18
2.4
Energy
Savings ......................................................................................................................20
2.5
Cost
Estimate ........................................................................................................................22
Appendix
1.
Site
Photos .......................................................................................................23
Figure
1.
Front
view
of
the
maintenance
building
and
environmental
office....................................23
Figure
2.
Rear
view
where
pellet
boiler
shed
will
be
added..............................................................23
Figure
3.
Tribal
admin
building
100’
behind
shop
building ................................................................24
Figure
4.
Current
oil
boiler .................................................................................................................24
Appendix
B.
Brochure
for
the
Froling
Pellet
Boiler ...............................................................25
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EXECUTIVE
SUMMARY
1.1
Acknowledgements
This feasibility study was supported by the Alaska Wood Energy Task Group and administered by the
Fairbanks Economic Development Corporation.
1.2
Objective
The objective of this report, as the title suggests, is to document the results of a pre-feasibility study
performed for the Village of Chickaloon. Buildings in the Village are currently heated with oil or
propane. The subject of the study is the feasibility of converting two buildings included in the study to
utilize an automated wood-fired heat boiler as the primary source.
Feasibility studies are often classified as Level 1 (L1), Level 2 (L2), or Level 3 (L3). Level 1 studies
consist of very rough calculations on a small number of important metrics (unit fuel costs, etc). Some
refer to L1 studies as “back-of-the-envelope” calculations.
At the other end, L3 studies are commonly called “investment grade studies”; the level of detail and
calculation is so high that one could use the results of an L3 study to get an outside entity to fund the
implementation of the project.
Level 2, then, is the bridge between L1 and L3; it is a screening study done to determine if it is worth the
time and expense to initiate an L3 study. Level 3 studies are generally quite expensive and thus not
entered into lightly. The L2 study helps decision makers determine which aspects, if any, of a proposed
project are worth the expense of an L3 study.
An L1 study can be done remotely; an L2 study requires at least a minimum amount of site observation of
existing conditions, conversations with the affected parties, and research with second-order parties (local
foresters, vendors, local contractors, etc). This is a Level 2 study.
Sustainability, Inc (SI) and efour, PLLC (efour) perform L2 and L3 studies across the state of Alaska,
from cities to small rural villages. We use the same performance and economic models for each type of
study; for us, the primary difference between the two studies is the quality of the inputs, which is
generally a function of how much time has been spent gathering information and the depth of that
information.
1.3
Sources
The primary sources of information that inform this study are data collected on site by SI and data
provided by the Fairbanks Economic Development Corporation (FEDC). Data collected on site by SI
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include existing site conditions, equipment name plate data, current energy cost data, and equally
important, information gathered by talking to the local stakeholders in the Village.
In addition, the Village has been actively pursuing a renewable solutions for the Village buildings,
including not only biomass heating, but solar thermal heating, solar photovoltaic power, and so on. They
have published some of their results in a Renewable Energy Plan. In terms of biomass heating, SI and
efour performed all their own analysis without reference to the Renewable Plan. However, we did extract
information from the Plan regarding the use of solar thermal panels to supplement the biomass boilers,
and incorporated that information into our results. We have not attempted to validate the solar thermal
performance and cost estimate data used in the Plan; we incorporated the information as published.
In addition to the site knowledge gathered by SI, additional biomass boiler performance and cost data
have been accumulated over the past several years from working with local engineers and contractors, and
from performing multiple L2 and L3 wood-fired feasibility studies.
Hourly weather data for the performance model was taken data collected and reported by Palmer
Municipal Airport, which is located about 30 miles away from Chickaloon, in the same river valley.
1.4
Scope
In Chickaloon, the scope of this report is limited to two buildings; A building that includes both a Shop
and the Environmental Offices (the Shop), and the Village Administration Offices (Admin Offices).
Currently, each building has its own heating system. The Shop utilizes an oil-fired boiler, while a
propane-fired heater heats the Admin Offices.
Biomass heating systems can be expensive to install; the economics generally work better for larger
buildings, or where two or more smaller buildings can be grouped together and served by a single
biomass boiler, using buried piping between the buildings to distribute the heat.
Taken alone, neither of the two buildings in this study is large enough to justify a biomass boiler – the
first costs are so high that the project economics are unfavorable under the public grant economic
approach. Chickaloon recognized this, and proposed grouping these two buildings into a common
biomass heating plant – the buildings are roughly 120 feet apart, so piping costs between the buildings are
minimal. SI and efour have followed this concept; we present the result only for a common heating plant
that serves both buildings.
As noted above, Chickaloon has proposed supplementing the biomass heat to these two buildings with
solar thermal heating panels mounted on the wall of the Shop. We have therefore presented the economic
and energy results in two forms – first without utilizing solar thermal, and then a second time including
the solar thermal cost and performance data as presented in the Plan.
1.5
Resource
and
Economic
Assumptions
SI and efour often perform studies on villages in Bush Alaska; off the toad system. In these villages,
biomass boilers generally have only two possible forms of fuel, wood chips or stick wood, both of which
they must produce themselves from local forests. Villages on the road system, however, have a third
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option; wood pellets produced elsewhere and trucked to the village. For small-scale projects, pellets are
in almost every way the best option.
The main reason is that the village need not invest in wood harvesting and processing equipment – they
simply buy the pellets. The cost per ton may be higher than chips, but the pellets are much drier, and
therefore have a significantly higher content per pound (BTU/lb) than wood chips. Pellets handle very
well, almost never fouling the material handling systems. They are not at risk of freezing as long as they
are kept dry; chips contain so much surface and internal moisture that freezing into clumps is an issue.
Equally important is that because of various issues, reliable chip-fired boiler can only be made so small;
we have not found any with an output capacity of less than 500,000 BTU/h (500 kBTU/h). Pellet boilers
can have capacities as low as 35 kBTU/h. The estimated combined peak-heating load of the Shop and
Admin Offices is 92.6 kBTU/h – so even the smallest chip-fired boiler is significantly too large. It can be
made to work, but the Village would be paying for a lot of boiler they were not using – this shows up in
the economic results.
Stick-fired boilers were not included in the discussion above. Stick wood is almost always the cheapest
in terms of $/BTU, and is always available in the Village (or can be collected locally). However, there
are no stick-fired boilers that have automated feed systems – they must be fed manually every few hours
(as often as every four hours in cold weather). If this labor is accounted for in the model, then this
generally reduces the economics of stick-wood boilers as an option.
Our model presents the results for all three fuel forms, but in Chickaloon, we would only recommend
pellet-fired boilers as this is the specific scenario that they requested after significant research and a
previous energy study for pellets.
Figure 1.1 below shows the assumptions that have been made for the existing fuels in the Village (oil and
propane):
Figure 1.1
Figure 1.2 shows the assumptions made for the cost of wood fuel, in various forms.
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Figure 1.2
Because each form of fuel has different heat content and is sold in differing units, direct comparisons of
the data in Figures 1.1 and 1.2 are very difficult. To make the comparison simple, all these energy
sources are converted to a common unit, one million BTU (1 mmBTU).
To make the comparison even more relevant, the conversion efficiency of each source has been factored
in. In this case, the conversion efficiency is the boiler efficiency. It is different for each fuel – using drier
wood results in better boiler efficiency, and the oil and propane boilers have their own efficiencies as
well. In Figure 1.3 below, therefore, the mmBTUs references are those coming out of the boiler into the
space, not the gross heat content of the fuel going into the boiler.
Figure 1.3
As expected, stick wood is the least expensive, followed closely by wood chips and wood pellets. Oil is
half again as much as wood, and propane is more than twice as expensive as any wood source.
Cost
Escalation
for
Fuels
Escalation in bush Alaska does not necessarily operate as it does in the lower 48, or even as it does in
other parts of Alaska. An entire year’s worth of oil for off road system village, for instance, is often
delivered by barge within a 3-month window when river conditions allow it. Thus the price might be
constant for an entire year, regardless of what happens to oil prices between the last barge of one year and
the first of the next year. If the barge company did not sell out of oil in the first, then that oil price might
apply for two years (especially if the year one cost was high and the year two cost dropped).
So oil costs in the bush escalate in a step-wise fashion, nevertheless, they do escalate over time, and we
attempt to choose a rate that provides a smooth, but reasonable prediction of future prices. At the same
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time, we try to avoid using escalation rates that are so extreme that the escalation rate alone makes the
project viable.
Over a 20 year time frame, even a “dog-of-a-project” can be made to look good if (for example) wood is
escalated at 3 percent a year, and oil is escalated at 8 percent a year. And yet, within the last few years,
oil was for a period escalating at 8 plus percent a year. For studies done during that period, one could
justify using an 8 percent escalation, but one would likely be disappointed if the project financial
depended on that rate remaining constant for 20 years.
In the Level 2 feasibility, we prefer to see if the project stands on its own, without relying on escalation.
In general, we use very low values, knowing they are likely conservative. For Alaskan villages, our
current escalation rates are 4.5 percent for oil, and 1 percent for wood. The reasoning for this is simple.
A long-term escalation rate of 4.5 percent seems to be supported in Alaska, so we use that value as a
lower bound. Labor tends to escalate at a lower rate (closer to 3 percent) and in fact wages have been
stagnant in the US for several years. In the villages, wage rates have little correlation to other markets, so
we assumed a low escalation rate for labor.
In most cases in Alaska, the wood itself belongs to the village, so its value is whatever the village says it
is – there is no underlying correlation to other market factors (there is no other market they can sell it
into) – so we assume the escalation rate of the wood to be zero. However, that wood has to be processed
and transported, although over smaller distances than most biomass, and that requires labor and oil (or
gasoline). Therefore, while we make no assumption that the cost of the underlying wood will change
with time, we use a one percent overall escalation rate for processed wood fuel based on the assumption
that the oil/gas/labor costs associated with processing and transportation will escalate the fuel costs at 1.0
percent.
Again, a Level 2 study is a screening study, and we believe that at this level, the project really should
prove its viability without relying on high rates of escalation. So we use the lowest reasonable rate that
we believe exists for oil, and then ratio the other rates down from there, based on their dependency on
outside market factors (in this case, petroleum). Electrical energy, for instance, is escalated at 3.0 percent
in the model because it is much more dependent on oil prices than wood fuel (but not directly correlated).
The intent in the Level 2 study is to get the escalation rate ratios “in-the-ballpark”, and get the overall
values as low as possible to minimize their impact on the financials. In the Level 3 study, the escalation
rates will be set by the entity financing the project, based on their due diligence, and the future rate risk
they wish to take on. As noted above, any project that relies on consistently high or widely divergent
escalation rates would be considered very risky from a financial standpoint, and unlikely to get
implemented. We would actually prefer to use zero percent for all rates at the L2 level, just to ensure the
underlying project is valid regardless of future rates; instead, we use the lowest rates we feel we can use
and worry more about the ratio of the rates that the values themselves.
In terms of risk, the reasoning is:
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1) If the cost of processing wood goes up significantly, the likely cause is that the cost of oil went up
significantly.
2) The cost of oil makes up 100 percent of the cost of fuel for an oil-fired boiler.
3) The cost of oil makes up only a fraction (although a significant fraction) of the cost of processed
wood fuel, THUS
4) Oil will always escalate faster than wood fuel – we simply chose to minimize this effect in the Level
2 study for the reasons stated above.
Pellet
Purchase,
Delivery,
and
Storage
Chickaloon’s environmental department did quite a bit of research on their approach to wood energy and
developed an energy plan that was reviewed and used in this report. In discussions with Chickaloon
personnel they told us that they had a plan for bulk delivery of pellets starting at $325 per ton and
included delivery costs from North Pole. The plan called for a silo storage bin that will feed into the
installed boiler. We used the fact that Froling boilers come with an adjacent pellet bin, which would
equate to a “day-tank” – that is, it stores several hours or a day’s worth of fuel, and is located very close
to the boiler (attached, in this case). For larger bulk storage, we assumed the building also includes a
Froling bag silo system, which would hold pellets for more than a week’s operation. Additional bulk
storage could be included in the village, or a larger bin could be constructed with a screw-type feed
system installed in lieu of the bag silo. This level of detail is generally decided in the investment grade
study. Freezing is typically not an issue with wood pellets if you do not let them get wet. The moisture
content is less than 5-10 percent, and this moisture is bound up mostly in the cells of the wood.
Pellet
Stoves,
Pellet
Boilers,
and
Solar
Heat
The study in Chickaloon was based on a previous report commissioned by the environmental department
and their request for reviewing their design. The large environmental department shop and office is too
large for multiple pellet stoves and will require a pellet boiler. The Tribal Admin building could be
heated with two pellet stoves if the client wished to do so. However, with 100 feet of pipe coming off a
building that will require a boiler, it makes sense to automate both buildings into one heating and pellet
feeding system. Solar heat under these circumstances does not add value to the system.
1.6
Summary
of
Economic
Findings
The following Figures summarize the performance and economic modeling that SI and efour performed.
As noted above, we show the results for pellet, chip and stick fired boilers, but we would only
recommend the use of pellet boilers in this case. The text of this section, therefore, deals only with the
pellet fired option.
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Figure 1.4 below shows the overall economic summary:
Figure 1.4
As footnote (1) indicates, we have not estimated any increase in annual maintenance with the installation
of the pellet-fired boiler. This is because the fuel consistency is so high, the material handling so smooth,
and the pellet boilers so reliable that in essence it is as close to being as automatic as an oil fired boiler
that a wood fired boiler can get. We would expect that whoever currently cares for the oil and propane
boiler will also take care of the pellet boiler, and that no significant additional time or parts expenses will
be incurred.
It was noted above that biomass boiler projects require a certain scale in order to be truly economical.
Even when the two buildings in Chickaloon are combined, they are quite small as biomass projects go.
This is reflected in the net simple payback of the project, roughly 17 years. Although the unit cost of oil
and propane are much higher than that of wood, the buildings are so small that the base fuel cost of fuel,
$12,488, is not large enough to offset the cost of the construction in a relatively short time frame, even if
all of the liquid fuel is displaced by wood energy (as is the case).
Note that the addition of the solar thermal option does not improve the project economics; the marginal
savings do not offset the marginal additional cost– thus the NSP get slightly longer with Solar included.
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Figure 1.4 is based on current fuel costs; these will not stay the same. Thus we present a 20 year cash
flow the project (pellets only). In this cash flow, the cost of all fuels is escalated, although not at the same
rate. Wood is assumed to increase in cost at a slower rate than oil or propane, because the resource is
local and renewable. The escalation rates used are shown in Figure 1.5:
Figure 1.5
Using these factors results in the following 20 year cash flows:
Figure 1.6
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Figure 1.7
In essence, the savings are projected to more than triple by year 20. For that reason, the high NSP of the
projects should not be enough to disqualify them. Renewable projects provide benefits beyond the
monetary ones. These decisions must be made at the Village level.
The final Figure of this subsection is a summary of the cost estimate. The complete construction estimate
is contained within Appendix B.
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Figure 1.8
Benefit
Cost
Ratio
The benefit to cost ratio is an attempt to capture the value of the project over the lifetime of the project. A
lifetime of 20 years is commonly used. The output of the calculations included is actually two numbers,
the actual benefit/cost ratio, and the net present value (NPV) of the project.
The project cost is a one-time event, but the savings accrue over the life of the project. Depending on the
assumed inflation rate of the various fuel sources, the savings may actually increase each year (if, for
instance, oil rises faster than biomass, as we have assumed). On the other hand, a dollar saved in year 20
is not worth a dollar today; it is worth the NPV of one dollar, at the assumed discount rate. The discount
rate is the rate of return one assumes one could make if that dollar were invested in some other fashion –
in a bank account, or on another project. The combination of one time and recurring costs, plus inflation
and discounting means that it would be very useful if the lifetime benefits, divided by the lifetimes costs,
could be boiled down to one number; the benefit to cost ratio.
The current year is always year zero for the calculation, and it is generally assumed that construction
would be completed in year one (or, for a long process or project, year two). The NPV of the project cost
for a project completed in year one is almost, but not quite the same as the project cost; it has only been
discounted one year. This is the COST part of the ratio. The BENEFIT is the NPV of the stream of
savings (fuel savings, in this case) that the project generates over the 20 year lifetime. Divide the Benefit
(in dollars) by the Cost (in dollars), and you get the dimensionless Benefit to Cost ratio; generally, any
value over 1.00 is considered good, but different agencies have different target values.
The NPV benefit is simply the NPV of the combined (savings minus cost) Cost and Savings cash flow
over 20 years. In the year the project is constructed, the “savings stream” is negative, because the
discounted project cost is much greater than the yearly savings – all other years, the savings are positive.
Take the NPV of that cash stream, and that is the NPV benefit of the project. Unlike the ratio, this value
only really tells one something useful when compared to another variant of the same project, or another
project that would use the same initial cash input. The project with the higher NPV benefit (in dollars) is
generally better.
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The NPV net benefit is $46,977 and the benefit cost ratio is 1.450 as demonstrated in Figure 1.9.
Figure 1.9
1.7
Next
steps
Based on economics alone, the project is marginal but the benefit cost ratioo is 1.45 and thus financially
doable. The real issue is the actual estimate of the Soft Costs in the project. Our standard is around 24%
of the total project to meet standards of a granting organization. However, these costs are probably higher
than necessary and should be considered by the granting agency in the ranking process for the projects
economic viability. Also, as noted above, the project generates benefits to the Village beyond the obvious
monetary ones. Among these are:
• Use of renewable resources
• Reliance on local, rather than remote energy sources
• Reduced carbon footprint
• Reduced secondary emissions (NOx, S, CO, etc)
• Increased fuel price stability (for future budget planning)
• Energy money spent remains in the local economy
There are no doubt others as well. As was noted above, a Level 2 study is a screening study, meant to
provide enough information to the stakeholders to A) determine how to proceed next, B) determine
whether to proceed, or C) halt the project until conditions improve. This study provides the information
needed for Chickaloon and other stakeholders to make these decisions; the next steps are up to them.
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TECHNICAL
SUMMARY
2.1
Existing
Conditions
The following statistics in Figure 2.1 summarize the existing conditions in the two buildings:
Figure 2.1
The proposed pellet-fired boiler would displace all of the liquid fuel consumption of the two buildings;
however, the existing systems would remain in place as back up. This is explained in more detail in 2.3.
2.2
Wood
Fuels
/
Wood
Fired
Heating
Equipment:
The model that SI / efour uses for these feasibility studies calculates the properties of wood fuels based
on: 1) species used (can be more than one), and 2) moisture content at time of burn. If more than one
species is selected, the model calculates a “composite” value for the fuel. For example, if one used 70
percent of a specie/moisture with 6,000 BTU/lb and the remaining 30 percent had a specie/moisture heat
content of 8,000 BTU/lb, the “composite fuel would have (0.7 * 6,00) + (0.3 * 8,000) = 6,600 BTU/lb.
Figure 2.2 shows the calculated properties for the pellets used in this analysis. The properties of chips
and stick wood are also calculated, but as noted above, the report is based on a pellet-fired boiler.
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Figure 2.2
The most pertinent value in the Figure is the net useable heat content, 8,017 BTU/lb. Because of the low
moisture content (5-10 percent), pellets are by far the densest form of wood fuel.
There are a number of manufacturers of pellet boilers; the basis of design boilers used in this study is the
P4 series of boiler made by Froling. There are eight sizes in the P4 series, ranging from 35.8 kBTU/h
output to 200 kBTU/h.
The basic system components include:
• A pellet bin, which holds bulk amounts of wood pellets.
o This bin is kept filled by periodic deliveries to the Village by truck
o Some trucks have an adjustable auger which can move the pellets from truck to bin
o Pellets can also be blown pneumatically, although that is more common in areas with
extensive pellet use
o Pellets can be “dumped” into a front loader, and then dumped in the bin
o There are a number of delivery and loading methods
• A means getting the pellets from the bin into the boiler (material handling)
o This can be an auger
o Froling offers an option that pneumatically conveys the pellets to the boiler (the pellets
are entrained in a moving stream of air)
• The boiler
o The boiler uses onboard controls to modulate the firing rate to meet heating demand
o Will remain on and operating as long as the bin is kept filled, and no fuel fouling occurs
o Is a “hands-off” unit
• A thermal storage tank
o This tank is basically a “wide spot in the pipe”
o It hold large amounts of water, thus large amounts of heat
o In essence, the boiler heats the tank, the tank heats the building
o Wood-fired boilers cannot change output as quickly as liquid fueled boilers; when
heating load is variable, the tank smoothes out the load and gives the boiler controls time
to react
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o When loads are very low, the boiler may shut down (it will automatically re-start when
needed); during these “OFF” periods, the tank provide a reserve of hot water
o By monitoring tank temperature, the boiler can “anticipate” when load starts to increase
or decrease, and thus provide more stable temperatures
• Solar Thermal Panels / pump / heat exchanger (if included)
o This system uses heat from the sun to supplement the wood-fired boiler
o The cooler return water from the buildings is routed to the heat exchanger before it gets
to the boiler
o In this way, the system always takes all of the available the free solar heat before using
the wood heat
o The tank even allows storage of solar heat if the available heat exceeds the heating load
• A vent or boiler stack
o This vents the products of combustion and boiler emissions into the air through an
elevated stack or vent pipe
o May or may not include additional emissions control equipment
Examples of the Froling boilers and accessories are included in Appendix A
Boiler
Maintenance
In general, when evaluating small biomass boilers that serve one or two buildings, we do not include
additional costs for maintenance associated with that boiler. This is not to say that there is not more
maintenance associated with a biomass boiler as compared to an oil-fired boiler. In terms of project
finance and viability, the point is not whether there is more maintenance or not, it is whether the
additional maintenance has any cost associated with it.
In general, the additional work associated with a wood-fired boiler consists primarily of removing ash
from the boiler once a day, and ensuring the feed bins or hoppers are full. Some larger chip-fired boilers
and almost all pellet boilers (including all the ones we propose) actually de-ash themselves, but all require
someone to fill the feed system. For stick-fired boilers, feeding the boiler is entirely manual and firing
may take place several times per day. For chips or pellets, one simply keeps a bin or hopper full,
depending on the bin size and the heating load, this may be required once or twice a week, and is
generally down with a Bobcat, front loader, or some equivalent.
Once a week one would spend perhaps an hour cleaning the heat exchange surfaces, and once a quarter or
half-year, one would take 2 – 4 hours to thoroughly clean the boiler tubes with a brush.
Of course, failures can occur, with the boiler or with the feed system. However, failures occur with oil
boilers as well, and the system as designed would automatically revert to the oil boilers in the event of a
biomass boiler failure. The maintenance personnel would then fix the biomass system when time permits,
as they do currently with equipment failures.
The costs associated with “non-failure” maintenance have up to three components; the cost of labor, the
cost of maintenance materials, and the costs of outside maintenance or operating contracts. Taking each
in turn:
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• Labor: This is the cost of people’s time. For this component, it is assumed that each village (or in
some cases, some individual buildings within the village) has someone on the payroll whose job is to
take of the existing oil-fired boilers. This may or may not be the entire scope of their job. If one
assumes that de-ashing and disposal takes 30 minutes a day, and loading the bin (chips and pellets)
takes an hour twice a week, and includes one hour per week for HX cleaning, then the day-to-day
maintenance of the biomass boilers takes an additional 6.5 hours per week. This figure does not
subtract out any time that would have been spent with the oil-fired boilers (which is no longer
required, because they are not running).
If a regular workweek for a full time employee (FTE) is 40 hours, this is 0.1625 of a week, or looked
at another way, 16.25 percent of an FTE. The question is, “Will the village actually hire someone full
or part time to perform those tasks, or we they simply add them to the scope of the work of the
existing FTE?” If they do not hire someone new, then there is no additional cost, even though there is
additional maintenance.
In our experience, at this very preliminary stage of evaluation, the villages simply do not know how
they would maintain one or more biomass boilers – they have no experience with them, and of the
time required. This should be developed with a conceptual design report and a business plan. It also
depends on how the fuel is generated and distributed. If an entity in the village takes on the making
and distributing of wood chips, for instance, then the time (and thus the cost) associated with filling
the fuel bins would almost certainly fall on that entity, and be built into the $/ton cost of the chips.
The same would apply for villages on the road system that purchase pellets. In such a case, the
additional maintenance would be reduced to the de-ashing (assuming the boiler does not do it
automatically) and periodic cleaning; we believe it highly unlikely that additional personnel would be
hired for these tasks. Thus we generally assume the value of this cost component to be zero at this
preliminary stage.
• Maintenance Materials: Biomass boilers require no maintenance materials that other types of
machinery (including oil-fired boilers) do not also require. Rotating machinery must be lubricated,
motors must be checked for balance or excessive heat, and so on. Once again, at Level 2 stage of
study, we assume the cost of this maintenance component to be zero as compared to an oil boiler.
• Outside Maintenance or Operating contracts: It may the case in some villages that an entity or person
creates a business to maintain and/or operate boilers within the village. In such a case, this business
would almost certainly charge an additional amount for operating and maintaining the new biomass
boilers. However, we not aware that such an entity exists in this case, and so once again, we have set
the cost of this component of maintenance to zero.
This leaves the extreme case of manual loading of stick-wood into stick-fired boiler. On a very cold day,
this could require several hours per day, spread over four six-hour periods (we generally size stick-fired
plants such that even in the coldest weather, they require no more than 4 “charges” per day). However,
even here, we cannot be sure there is added cost – a tribal office might, for instance, simply require
everyone on the staff to take turns loading the boiler. Alternately, they might hire one or more FTEs to do
this.
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The number of variables is very large, and at the Level 2 stage, we find that villages simply have not
given much if any thought as to these matters. The L2 study is a screening study, used to decide whether
or not to proceed to with a project and to a conceptual design study that should define the project more
specifically at an investment grade level; if the results of the L2 study are favorable, then the actual
maintenance costs (if any), as well as a number of other operating details, are thoroughly determined and
documented.
2.3
Proposed
Configuration
The proposed final configuration, which has been modeled for this study, can be summarized as:
• A new 8 x 20 mechanical room is constructed on the back side of the Shop
• The new pellet boiler, pellet bin, and material handling accessories are installed in the
mechanical room
• The thermal storage tank is installed in the mechanical room
• The solar thermal panels, if used, are mounted on the south side of the shop; the remaining
system components are installed in the new mechanical room
• The heat from the wood fired boiler is piped into the existing Shop mechanical room using
copper pipe
• The heat from the wood fired boiler is also piped to the Admin Office mechanical room,
using a combination of insulated plastic pipe (direct buried) and copper pipe (once inside the
building
• The plastic pipe proposed is a system called Insulpex, by Rehau; details can be found in
Appendix B
• The new piping will be tied into the existing systems in such a way that will always take the
“wood heat” before taking oil/propane heat (see details below)
• However, if for any reason the wood fired system cannot meet load, the existing boilers will
automatically start and fire as required to meet load
Figure 2.3 below shows a typical configuration for an oil-fired boiler or boiler plant. In this example,
there are two boilers, but only one runs at a time. In Chickaloon, there is only one, but the integration of
the systems is the same. This would be the “existing” case.
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Figure 2.3
Figure 2.4 shows the proposed case (valves colored in solid are closed):
Figure 2.4
In this case, valve 1 is closed, which forces the hot water return water through the wood fired boiler
instead of the oil-fired boiler. Likewise, valve 4 is closed, so the hot water from the wood-fired boiler
bypasses the existing boilers and goes out to the building. If for any reason, the hot water supply
temperature falls below set point by a set amount, the valves reverse position, and the existing boiler start.
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In an even simpler version, there are no automatic valves – the cooler return water flow through the (solar
thermal heat exchanger, if installed), the wood-fired boiler, and then the oil / propane boilers. If the solar
system meets set point, no boiler fires. If the solar system cannot heat the water to the supply set point,
the wood-fired system fires as needed to provide the additional heat required. If for any reason the wood-
fired system still does not meet supply water set point, the existing boiler fires.
The system works because each successive set point is set 5 or more degrees below the previous one. Say
the three hot water supply set point was, in order, 185 deg F, 180 deg F, and 175 deg F. If we take a day
when the solar heat is meeting load, the system would be delivering 185 deg F water. Perhaps a cloud
goes by and the available solar energy dips. By having a 5 deg F spread in set points, this prevents the
wood-fired boiler from starting every time a cloud goes by. Likewise, it was noted above that wood-fired
boilers cannot modulate output as fast as a liquid-fired boiler. The set point spread prevents the existing
boilers from firing every time the wood fired boiler needs a bit of time to catch up (as does the thermal
storage tank). At the same time, the system requires no operator intervention or automated controls. If
the hot water temperature falls to 174 deg F, the oil-fired boiler does not know if the sun went down, or
the wood pellets fouled the material handling system – it simply fires because the supply temperature has
fallen below its set point.
2.4
Energy
Savings
Figure 2.5 below summarizes the energy consumption, existing and proposed, on a monthly basis:
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Figure 2.4
Note that the last two segments of Figure 2.4 show the savings with and without the solar thermal system.
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2.5
Cost
Estimate
The construction cost estimate is provided below. These what are commonly referred to as the “hard
costs”. The remaining soft costs, fees, permits, etc, are detailed in Section 1.
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Appendix
1.
Site
Photos
Figure
1.
Front
view
of
the
maintenance
building
and
environmental
office.
Figure
2.
Rear
view
where
pellet
boiler
shed
will
be
added.
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Figure
3.
Tribal
admin
building
100’
behind
shop
building
Figure
4.
Current
oil
boiler
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Appendix
B.
Brochure
for
the
Froling
Pellet
Boiler
P4
Pellet Boiler
• Fully automatic
• Super high efficiency
• Bulk or bag wood
pellet ready
• Plug & play
– no assembly
• Includes solar-thermal
controls for
easy integration
• Very clean
• Very safe
June 2012
Visit www.woodboilers.com for more
information about this boiler including
videos and installation planning documents.
®
Fröling P4 Applications
❚ stand alone boiler or add on to your
existing fossil-fuel heating system
❚ can provide domestic hot water
❚ hydronic heating systems such as radiant
floor, baseboard, and hydro-air
Pellet Boiler
P4
Independence and Self-reliance
Fröling P4 boilers provide a convenient,
safe and environmentally responsible way
to heat your home and hot water with
wood pellets. P4 homeowners are assured
of unusually high heating efficiency, low
heating costs, and use of an abundant,
locally available, renewable fuel. With its
ingenious, fully automated operation, this
boiler is amazingly easy to use.
Innovation
❚ Pneumatic pellet feed is ideally suited
for bulk fuel applications, although the
P4 may be used with bagged fuel.
❚ Variable speed induced draft fan
ensures optimal fuel-to-air ratio.
❚ Incoming combustion air temperature
is raised with an integrated pre-heating
system.
About Tarm Biomass®
Tarm Biomass® is a third-generation, family-owned business that has pioneered the sales and service
of residential central heating equipment in North America for over 30 years. TarmBiomass'® primary
objective is to offer innovative home heating solutions, along with a significant commitment to
consumer education and environmental awareness. Exclusive partnerships with ISO 9001 certified
manufacturers allows Tarm Biomass® to offer products with operational reliability, unique firing
efficiency, and to promote the clean burning of carbon-cycle biomass that is critical to the lowering of
net greenhouse gas emissions.
About Fröling
Founded in 1961, Fröling is a family-owned company located in Grieskirchen, Austria. A pioneer in
wood-fired heating systems, Fröling has devoted decades of intensive R&D to the study of maximum
energy efficiency.
❚ Cascade control system for systems
requiring multiple boilers.
❚ Multiple-pass heat exchanger and
automatic heat exchange cleaning
provide maximum efficiency
and exceptional fly ash separation.
❚ Integrated storage tank control.
❚ Rated outputs from
36k BTU/hr to 200k BTU/hr.
❚ Systems to 800k BTU/hr.
❚ Exhaust temperatures under 250°F.
❚ Must be installed with a moderately sized
buffer tank to reduce on/off cycling for
optimal efficiency.
❚ Ash separation to two drawers.
❚ Virtually silent operation.
Bulk Delivery
As the North American pellet market
matures, more and more people are able
to take advantage of bulk fuel delivery.
With bulk delivery, a pellet fuel truck
delivers several tons of loose pellets to
your home fuel storage bin or silo. The
pneumatic feed device built into the P4
automatically delivers these pellets to
your boiler as needed. The convenience
of fossil fuel delivery with the economic
and environmental benefits of biomass
Pellet Storage Systems
There are several options available for
pellet storage:
Auger/pneumatic—ideal for
rectangular rooms with front-end
removal. Complete emptying guaranteed
due to deep and horizontal position of
the delivery screw. Use with the suction
system for flexible boiler setup.
Bag silo—flexible, simple and easy to
assemble. Dustproof and flood proof, this
system can be installed outside with the
addition of rain and sun covers.
is what some would call the ultimate
solution for your home heating needs.
For those who do not have access to bulk
pellet delivery, the P4 may easily be used
with bagged fuel.
Universal Suction— Three suction
probes positioned uniformly provides
complete emptying of the pellet store
room.
Features
❚ Over 85% efficiency
❚ automatic ignition
❚ automatic sliding grate in combustion chamber
❚ insulated cleaning door for heat retention
❚ soundproofing for almost silent operation
Advantages
The P4’s compact design allows for easy
positioning, even in a confined space. The
disassembled unit fits through a 36” door.
It arrives fully wired and ready for use. An
integrated silencer ensures quiet operation.
How it Works
The P4 represents the most advanced residential pellet boiler technology available. Fully automatic ignition, coupled with a programmable
user interface, automatic fuel feed and automatic ash removal means the P4 is extremely easy to use and requires very little maintenance.
Please visit our website for a complete overview.
Lambdatronic P 3200 control system
This large, clear control unit with an adjustable
viewing angle provides English language prompts
in a logical menu system. Diagnoses and trouble-
shoots all boiler systems. Brilliantly engineered
for easy operation using today’s most advanced
control technology.
Disclaimer
Tarm Biomass® is not responsible for factory alterations to measurements.
For final specifications, please see the Fröling P4 Owner’s Manual. Image
used for informational purposes only. Actual appearance may vary.
State-of-the-art robotics technology within
Fröling’s manufacturing plant.
4 Britton Lane | P.O. Box 285 | Lyme, NH 03768 | 800.782.9927 | info@tarmbiomass.com | www.tarmbiomass.com
Fröling sets new international standards for
technology and design within their Austrian facility.
European innovation extends to every facet of
Fröling's state-of-the-art facilities.
Technical Data Model 8 Model 15 Model 20 Model 25 Model 32 Model 38 Model 48 Model 60
Rated heat output BTU/hr 35,800 50,800 68,200 85,300 109,000 129,650 163,800 200,000
Rated heat output kW 10.5 14.9 20.0 25.0 32.0 38.0 48.0 58.5
Heat output range kW 3.1-10.5 3.1-14.9 6-20.0 7.5-25.0 8.9-32.0 8.9-38.0 14.4-48.0 17.3-58.5
Electrical power W 9 6 1 23 110 110 110 110 120 120
consumption (@240V )*
Water capacity US gallons 18.5 18.5 21 21 33 33 45 45
*Numbers shown are normal operating figures. Peak intermittant consumption is higher.
Installation Data Model 8/15 Model 20/25 Model 32/38 Model 48/60
Boiler
length1 inches 291/8 291/8 321/4 351/2
length w/induced draft fan inches 37 37 401/8 431/4
width2 inches 235/8 303/8 333/4 401/2
width w/support inches 273/4 34½ 38 50¼
width w/feed cyclone inches 465/8 533/8 563/4 701/2
height3 inches 50 3/8 50 3/8 56 3/8 623/8
height w/feed cyclone inches 653/8 653/8 747/8 747/8
Boiler dry weight4 pounds 706 882 1032 1675
Flue collar height inches 531/8 531/8 601/4 663/8
Flue pipe diameter inches 5 5 6 6
1 Corresponds to the minimum poitioning length.
2 Width of the boiler including support for positioning unit. Corresponds to the minimum positioning length after removing the stoker fitment, suction cyclone and positioning unit.
3 Corresponds to the minimum positioning height after removing the stoker fitment, suction cyclone and positioning unit.
4 Specified weight refers to the boiler without ash removal module.
Listed AppliancePressure tested in accordance with EN 303-5, NON-ASME
June 2012
®