Science: Reasons for not installing a woodchip boiler

Reasons for not installing a woodchip boiler

Sustainability Coordinator

Office of the Provost
63 South Main, Room 316
HB 6011
Dartmouth College
Hanover, NH 03755-3529
Dartmouth College

1. Greater CO2/BTU

Wood chips                 221.943 pounds of CO2 per Million BTU

#6 oil                           173.906

#2 oil                           161.386

Solar Thermal              0

2. Accelerates greenhouse gas emissions -- Instantaneous release of carbon through burning which would take decades to release through decay

3. Dangerous trend for New England Forests -- Trades negative impacts, without clear ecological benefit. 

Benefits: releases carbon on earth's surface, local fuel source, reduce dependence on foreign oil

Costs: Consumes large amounts of bioproductivity at a time in history when extinction rates are 100 to 1000 times faster than historic levels (due to habitat loss and human encroachment), the planets forests cannot sequester the carbon currently released and we have better alternatives. 

4. The alternatives to a woodchip boiler could be further explored.  Quantum efficiency and conservation programs would also reduce expenses, but also be a clear environmental solution reducing greenhouse gas emissions and environmental impacts. 

5. Forests have the highest value of all land types for ecosystem services.

$33 trillion / 28 million acres = 1.2 million /acre

Bob Costanza at the University of Vermont developed a methodology that assigns a monetary value to 17 ecosystem services.  These include soil formation, recreation, nutrient cycling, water regulation and supply, climate regulation, habitat, flood and storm protection, food and raw materials production, genetic resources, atmospheric gas balance and pollination. A team of researchers from the United States, Argentina, and the Netherlands has put an average price tag of US$33 trillion a year on these fundamental ecosystem services, which are largely taken for granted because they are free. That is nearly twice the value of the global gross national product (GNP) of US$18 trillion [1] What is the value of forests ecosystem services compared against industrial logging?

6. Woodchips have no value added component.  Some European countries get over 10 times the jobs per unit of wood cut.  Woodchips, pulp and dimensional lumber are the least value-added products possible.  Burning biomass in 2006 seems a crude use of bioproductivity.

7. The quantity needed to provide energy to an economy or system that has not done their conservation work first it large. As a back of the envelope calculation:

About one cord a year translates into a 1.9 acre footprint (from my book Radical Simplicity) this figure is adjusted to world average forest productivity so someone in Africa on land with lower productivity wouldn't be unfairly measured.  Our forests in New England are about double world average forest productivity.

8. Scientific community is not in agreement as to biomass fuels carbon spectrum over time.  Younger forests have shallower roots and if managed by frequent rotations will likely deplete surface nutrients and compact soils.

Stands managed as old growth sequester more carbon:

25 year old forest: 12,000 lbs of carbon / 25 = 480 lbs of C per acre per year x 44/12 =1,760 lbs of CO2 per acre per year

120 year old forest: 128,000 lbs of carbon / 120 = 1,066 lbs of C per year per acre x 44/12 =3,909 lbs of CO2 per acre per year

9. I don't see there being an ecological free lunch -- that is to say, woodchips being a so-called waste, could build soil adding carbon and nitrogen, duff, water retentionÉ  As a gardener knows, if you continue to take from the land without returning nutrient, the land slowly degrades.  What is the long term effect of forests after several industrial logging operations?   How soon would even so-called waste-food be consumed leaving trees to be chipped?  A BC forester, Herb Hammond, said that it can take 250 years for creek timing and flow patterns to return to normal after an industrial logging operation.

10. I feel like I need to apologize, I love forests.  IÕve walked miles of industrial forests.  To get the volume needed to feed municipal of institutional boilers requires industrial impacts to the landscape. 

Here is some more detailed ideas:

The model should be inclusive of multiple factors and include feedback loops so each project learns and adjusts future steps based upon a growing information base and experiential wisdom.

As an example, the following factors influence a building's emissions:

Area per occupant -- A

Technology of systems -- T

Envelope effectiveness -- E

Operational controls - O

Management effectiveness - M

User habits - U

Extending useful life -- L

Emissions/BTU of fuel source -- F

Total building performance = A x T x E x O x M x U x L x F

If we designed for a performance increase in each factor by a "best practices" margin, total system performance can be radically improved as factors multiply by one another. Assume "1" to be current practices and that the following usage reduction multipliers could be achieved.

Area per occupant -- 0.8 (20% reduction)

Technology of systems - 0.7

Envelope effectiveness - 0.5

Operational controls - 0.9

Management effectiveness - 0.9

User habits - 0.8

Extending useful life - 0.8

Emissions/BTU of fuel source - 0.8

The total building emissions now become the following fraction:

= A(0.8) x T(0.7) x E(0.5) x O(0.9) x M(0.9) x U(0.8) x L(0.8) x F(0.8)

= 0.116 or an 8.6 fold increase in performance.  Isn't multiplication exciting?

Suggested Strategies for Campus Emission Reduction

A comprehensive plan would include but not be limited to the list of strategies below used in the suggested ranking by preference. An assessment of the potential reduction possible through each strategy could be plotted against goals and milestones.

a.) Freeze emission growth. Attempting to reach a moving target is discouraging. All new programs and initiatives could be required to demonstrate carbon neutrality. Ensure each new building completed is carbon neutral through efficient design, on-site energy production and purchase of renewable energy credits and/or offsets. A commitment to not allowing the target to continue to grow would inspire creative problem solving and management. Accepting that limits exist (design constraints) can foster ingenuity.

b.) Reducing the use of fossil fuels (direct and embodied) through resource efficiency and conservation in all our operations including commuting. Factors included would mirror the example given in 4.2 above applied to campus systems as well as individual systems. These multiplying factors would include: Utilization, Technology, Building Performance, Operational Decisions, Administrative Drivers, Management Effectiveness, User Habits, Energy Choices...

c.) Optimizing the utilization and care of assets. Decisions to demolish buildings should be preceded by a detailed economic and ecological footprint analysis that would compare a tear-down to a strategic retrofit. Preventive maintenance and extending the useful life can dramatically reduce impacts.  A building torn down half-way into its useful life doubles its construction and disposal footprint. Demolition typically releases toxic substances into the environment and the salvage value is a fraction of the asset's value. A study conducted in Bellingham Washington determined the value of salvage materials to be $1.04 per sq ft. New construction at Dartmouth typically costs over $250 per sq ft. 

o          Footprint of 100,000 square foot 40-year building: 100,000 x 12.2 ff = 1.22 M sq ft./4840 = 252 acres, with 45 acres being the energy footprint.

o          Disposal footprint if land filled: 100,000 x 13.48lbs/sq ft x 481 ff/40yr/12mo = 1.35 M sq ft./4840 = 279 acres  

o          Disposal footprint if recycled: Approximately half that of sending it to the land fill or 140 acres.

Factor: 0.8

d.) Fostering an environment of commitment to excellence in sustainable daily practices beginning with staff, faculty and administration spreading into student life. Behavior changes can yield significant reductions. For example, the benefit of a vehicle that is 20% more efficient is erased if we travel 20% more. Efficiency coupled with behavior however has a multiplying effect; i.e. 20% more efficient coupled with a 20% reduction in vehicle miles traveled yield a 40% decrease in CO2. Critical to any comprehensive program is education and buy-in to the initiatives objectives.

Factor: 0.7

e.) Burning cleaner fuels.

Factor: 0.9  

f.) Installing renewable energy equipment such as solar thermal and photo voltaic panels on campus.

Factor: 0.9

g.) Purchasing renewable wind and solar energy credits.

Factor: 0.8

h.) Establishing procurement guidelines aimed at purchasing commodities such as food, services, materials and supplies from businesses with documented sustainability practices located within the local region.

Factor: 0.8

i.) Managing our land holdings for ecosystem services including biodiversity, air quality, carbon sequestration, soil stabilization, watershed integrity, wilderness and cultural values. The college owns 39,356 acres of lands of which 384 acres have conservation easements. This land can be managed such that the carbon stored on the land (volume of standing trees) increases each year.  Either through restoring lands or documenting an increase in stored carbon, this land could be used to offset remaining CO2 after items a-h above have been completed. 

Tufts climate Initiative reports that a Northeast, maple-beech-birch forests will sequester

CO2 according to the age of the stand as follows:

25 year old forest: 12,000 lbs of carbon / 25 = 480 lbs of C per acre per year x 44/12 =1,760 lbs of CO2 per acre per year

120 year old forest: 128,000 lbs of carbon / 120 = 1,066 lbs of C per year per acre x 44/12 =3,909 lbs of CO2 per acre per year

For this example, we will use the lower number applied to Dartmouth's 39,356 acres:

Pounds of CO2 sequestered per acre per year: 1,760 lbs/acre/yr

39,356 acres x 1,760lbs/acre/yr. = 69.27 x 10exp6 lbs/yr

For a 120 year old stand: 39,356 x 3,909 lbs/acre/yr = 153.84 x 10exp6 lbs/yr

j.) Purchasing of carbon offsets. These can currently be purchased for $10/metric ton of CO2.

k.) Usage of plant-based fuels. There is an increase in carbon emissions per BTU from burning woodchips compared to #6 fuel oil: 221.9 vs. 173.9 pounds of co2/10exp6 BTU.

Bio diesel from waste oil can be an interim strategy while available; however, our large consumption of heating oil far exceeds regional French fry production. Virgin bio diesel is not recommended due to the impacts of converting forest lands to mono-cultures or using crop land for energy. The trading of externalities, ecosystem services and world food supply (one billion humans face debilitating poverty) need careful evaluation. 

[1] Adapted from R. Costanza et al., "The Value of the World's Ecosystem Services and Natural Capital," Nature Vol. 387 (1997), p. 256, Table 2.

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