COMPARISON OF DARTMOUTH COLLEGE EXISTING COGEN PLANT AND NEW HEATING PLANT

The existing Dartmouth campus central cogeneration plant required about 3.5 million gallon of No. 6 fuel oil in 2018. The plant had a minimum heating load of 4 MW (13.65 million Btu/h) in summer and a maximum of 32 MW (109.2 million Btu/h) in winter. See page 11 of URL

 

The Dartmouth campus required about 50000 MWh of electricity in 2018, of which about 80% was purchased and the existing co-gen plant generated about 20%.

 

https://www.sustainability.dartmouth.edu/energy

https://dartmouth.app.box.com/s/6bs4ivyc67q9hg63g89j33jnfo0vl223/fi...

 

The existing steam plant would be replaced by:

1) A new 16 MW (54.6 million Btu/h), wood chip fired, hot water boiler plant. 

2) A new 32 MW, biodiesel-fired, hot water boiler plant (80% petroleum diesel/20% biodiesel), which would provide:

 

- Any heating from 0 MW to 16 MW, in case of the wood chip plant having a scheduled or unscheduled outage, or not being able to efficiently operate at low summer loads

- Any heating above 16 MW, up to a maximum of 32 MW, during the colder days of the year, about 1500 hours.

 

Dartmouth College Buildings are Energy Hogs

 

They use about 70,000 Btu/sq ft/y just for heating. See table 1.

 

Highly sealed, highly insulated buildings would use 20,000 to 25,000 Btu/sq ft/y for heating, plus they would need Btus for any cooling, plus Btus for electricity.

 

It appears to me Dartmouth College should first attend to building energy efficiency, before committing to a “politically correct”  (but not so benign) new wood burning plant.

 

http://www.windtaskforce.org/profiles/blogs/co2-emissions-from-logg...

http://www.windtaskforce.org/profiles/blogs/burning-wood-produces-e...

https://www.sustainability.dartmouth.edu/energy

https://www.vnews.com/Column-Burning-Forests-for-Heat-at-Dartmouth-...

http://www.windtaskforce.org/profiles/blogs/dartmouth-s-planned-bio...

 

Heat to Buildings and CO2 of No. 6 Fuel Oil Plant

 

Combustion CO2 of No. 6 fuel = 75.04 kg/million Btu, or 2.20462 x 75.04 = 165.43 lb/million Btu

Upstream CO2 of No. 6 fuel oil = 28.19% of combustion CO2 = 46.63 lb/million Btu

Total CO2 = 212.06 lb/million Btu

https://www.epa.gov/sites/production/files/2015-07/documents/emissi...

It is assumed the existing No. 6 fuel oil plant has an annual average efficiency of 75% and the steam distribution system has a loss of 10%, for a net efficiency of 75 - 0.1 x 75 = 67.5%. See table 1.

The heat supplied to the boiler is based on the lower heating value of No. 6 fuel oil.

See table 1A.

 

Table 1/Heat to buildings and CO2 of No. 6 fuel oil plant

Buildings

120

Building area, sq ft

5000000

Fuel consumption, No. 6 fuel oil, gallon/y

3500000

Electricity

.

No. 6 fuel oil heating value, LHV, Btu/gal

146974

Boiler efficiency, %

75

Distribution heat loss, %, 10% of 75

7.5

Efficiency, %

67.5

.

Heat from fuel, billion Btu

514.4

Heat to buildings, billion Btu

347.2

Heat to buildings, Btu/sq ft/y

69445

 

Table 1A/CO2 emissions from No 6 fuel oil

Combustion CO2, lb/million Btu

165.43

Upstream, % of combustion CO2

28.19

Upstream CO2, lb/million Btu

46.63

Total CO2, lb/million Btu

212.06

No. 6 fuel oil consumption, gal/y

3500000

LHV, Btu/gal

146974

Heat supplied to boiler, million Btu/y

514409

CO2, lb/y

109086256

2000

CO2, US ton/y

54543

2204.62

CO2, metric ton/y

49481

 

* Excludes 1) downstream CO2 of energy for decommissioning and reuse/landfill, 2) embedded CO2 of A to Z infrastructures, 3) CO2 of electrical and vehicle diesel fuel energy of plant operation and any electrical energy of steam distribution system.

See table 3A.

 

CO2 Emissions of New Plant

 

Table 1B/CO2 Emissions of New Plant

Combustion

Upstream

Total

 

Metric ton/y

Metric ton/y

Total metric ton/y

Wood chip plant

38413

3841

42254

Biodiesel B20 plant

6751

3054

9805

Both plants*

42254

9805

52058

 

* Excludes 1) downstream CO2 of energy for ash disposal + 2) decommissioning and reuse/landfill, 3) embedded CO2 of A to Z infrastructures, 4) CO2 of electrical and vehicle diesel fuel energy of plant operation and any electrical energy of hot water distribution system.

See table 3A.

NOTE:

In case of clearcutting, any of our biomass combustion CO2 of year 1 would have to wait around in the atmosphere until about year 35 to start its absorption period, which takes about 80 to 100 years in colder climates. See URL.

After our biomass combustion CO2 is fully reabsorbed by new tree growth on our harvested area, it has fulfilled the assertion: “Burning wood is renewable”.

In case of light and medium cuts, that waiting period would be shorter. See URL.

Other CO2 (upstream, downstream, embedded, plant operation, distribution system operation, etc.), which is not biomass combustion CO2 of wood chips, would be added to the atmosphere just like any other CO2.

http://www.windtaskforce.org/profiles/blogs/co2-emissions-from-logg...

NOTE:

Boiler efficiency = heat (as steam or hot water) out of boiler / heat from fuel into boiler.

Plant efficiency = heat (as steam or hot water) out of boiler/ (heat from fuel + energy for electrical usages + diesel fuel, etc. into plant)

Heating system efficiency = heat (as steam or hot water) out of boiler/ {(heat from fuel + energy of electricity usages + diesel fuel, etc. into plant) + a percentage of heat out of boileras distribution system heat loss}

A to Z efficiency = heat (as steam or hot water) out of boiler/ {(heat from fuel + energy of electricity usages + diesel fuel, etc. into plant) + a percentage of heat out of boileras distribution system heat loss}+ upstream energy + decommissioning + reuse/landfill energy + embedded energy of A to Z infrastructures)}

NEW WOOD CHIP FIRED HOT WATER HEATING PLANT

No.6 fuel oil is a highly defined fuel. Its combustion properties vary within defined narrow bands. However, wood chips have various heat contents depending on type of tree, what part of a tree, location, time of logging. An Internet search showed a spread of values. I have chosen the lowest value, as that gives the highest tonnage. It is better to plan fuel handling systems for too much tonnage than too little.

 

The Dartmouth College-Biomass Fuel Supply Assessment, page 19, assumes wood chips would have average moisture of 45%, by wgt, and heat content of 4625 Btu/green lb, or 9.25 million Btu/green US ton. That is the same value used by Maine. The heat content would be 4625/0.55 = 8409 Btu/lb, dry. That is slightly less than the generally accepted HHV of 8600 Btu/lb, dry.

 

NOTE: The Maine value is high because it has a lot of soft wood pine trees which have higher heating values than the hard wood oak, maple and birch trees more prevalent near Hanover. Other entities use lower values. See below list.

 

Variations in Heat Content of Wood Chips:  There appears to be a variation of heat content values of wood chips.

 

9.25 million Btu/green ton (45% m. c.), or 9.25 million/2000/0.55 = 8,409 Btu/lb, dry. See page 33

https://formaine.org/wp-content/uploads/2019/04/FOR-Maine-Wood-Ener...

8.6 million Btu/green ton (50% m. c.), or 8.6 million/2000/0.5 = 8,600 Btu/lb, dry

https://www.fpl.fs.fed.us/documnts/techline/fuel-value-calculator.pdf

8.6 million Btu/green ton (50% m. c.), or 8,600 Btu/lb, dry

http://ipm.uconn.edu/documents/raw2/846/Evaulating%20Wood%20heat.%2...

8.0 million Btu/green ton (50% m. c.), or 8,000 Btu/lb, dry

https://ag.umass.edu/fact-sheets/wood-heat-for-greenhouses

7.6 million Btu/green ton (45% m. c.), or 6,909 Btu/lb/dry

http://ipm.uconn.edu/documents/raw2/Approximate%20Heating%20Value%2...

 

Heating Provided by Wood Chip Plant: Based on the generally accepted HHV of 8600 Btu/lb, dry, the heat from the boiler to the hot water distribution system would be 6398 Btu/lb, dry, after all losses are applied. See Appendix.

 

It is likely hot boiler exhaust gases would be used to pre-dry the wood chips to about 15 to 20% moisture, but that heat has to be provided by the wood fuel fed into the boiler.

 

Electricity and Vehicle Fuel Input: The plant requires electricity and fuel to operate its:

 

1) Fuel system (receiving, storing, pre-drying, delivering to boiler),

2) The boiler plant pumps, fans, etc.,

3) Ash handling system, and

4) Flue gas cleaning systems.

5) Misc. electrical services (lighting, AC, office, etc.)

 

The total electricity and vehicle fuel input is assumed equivalent to at least 6% of the wood fuel input, i.e., 6% of 8600 = 516 Btu/lb

Fuel Supply and CO2 Emissions of New Plant

 

Heat entering buildings = 347,200 million Btu/y. See table 1

 

Heat from wood chip plant entering buildings = 4 MW x 7000 h + 12 MW x 1500 h + 12/2 MW x (7000 - 1500) h = 82,000 MWh, or 280,000 million Btu/y), based on Dartmouth load duration curve.

The wood chip heating plant would provide about 280000/347200 = 80.6% of the heat entering buildings, which would require 53830 ton of wood chips.

 

Heat from B20 biodiesel plant entering buildings = 347200 - 280000 = 67200 million Btu/y, or 19.4%, which would require {67200 million Btu/126700 Btu/gal, LHV}/(0.80, boiler efficiency* - 0.08 x 0.80, distribution loss) = 720,634 gallon of B20/y. See Appendix and URLs.

* Boiler efficiency is based on LHV.

https://h2tools.org/hyarc/calculator-tools/lower-and-higher-heating...

http://nhcleancities.org/2017/04/can-compare-energy-content-alterna...

https://afdc.energy.gov/fuels/fuel_comparison_chart.pdf ;

Combustion CO2 of Wood Chips = 93.80 kg/million Btu, or 2.2046 x 93.80 = 207 lb CO2/million Btu of heat into the wood chip plant

Heat supplied by wood chip plant to buildings is 280,000 million Btu/y

Combustion CO2 Emissions of Wood Chip Plant = (280,000 million Btu x 207 lb/million Btu)/(0.684, see table 4/2204.62 lb/metric ton) = 38413 metric ton/y.

 

There would be about 10% of upstream CO2 that has nothing to do with combustion, in case of wood chips, about 15%, in case of wood pellets. This includes CO2, such as fuel used for logging, chipping/pelletizing and transport.

 

Total CO2 from wood chip plant = 38413, combustion + 3841, upstream = 42254 metric ton/y

 

Combustion CO2 of B20 = 73.84 kg CO2/million Btu, or 2.2046 x 73.84 = 163 lb CO2/million Btu

Heat supplied by biodiesel plant to buildings is 67,200 million Btu/y.

Combustion CO2 emissions of B20 Plant = (67200 million Btu x 163 lb/million Btu/0.736, efficiency)/2204.62 lb/metric ton = 6751 metric ton/y.

 

There would be about 45.24% of upstream CO2 that has nothing to do with combustion. This includes CO2, such as fuel used for cropping, processing, blending and transport.

 

Total CO2 from B20 plant = 6751, combustion + 3054, upstream = 9805 metric ton/y    

https://www.epa.gov/sites/production/files/2015-07/documents/emissi...

 

Total CO2 from both plants = 42254, combustion + 9805, upstream = 52058 metric ton/y*. See table 3A

 

* Excludes 1) downstream CO2 of energy for ash disposal, 2) decommissioning and reuse/landfill, 3) embedded CO2 of A to Z infrastructures, 4) CO2 of energy of plant operation and hot water distribution system.

 

Table 3A/Fuel supply and CO2 emissions

Heat entering buildings, million Btu/y

347200

Total

Wood chip

B20 biodiesel

Heat entering buildings, million Btu/y

280000

67200

Heat content, Btu/gal, LHV

126700

Boiler thermal efficiency

0.80

Distribution loss

0.08

Efficiency, 0.80 - 0.08 x 0.80

0.736

B20 supply, gal/y

720634

Efficiency, (6398 - 512)/8600

0.684

0.736

Heat to boiler, million Btu/y

409106

91304

CO2, lb/million Btu fed to boiler

207

163

Combustion CO2, lb/y

84685015

14882609

Combustion CO2, US ton/y

42343

7441

Combustion CO2, metric ton/y

38413

6751

45163

Upstream, %

10.00

45.24

Upstream CO2, metric ton

3841

3054

6895

Total CO2, metric ton/y

42254

9805

52058

  

Table 3B/Heat to buildings, million Btu/y

347200

 

Fuel

Wood Chip

B20 biodiesel

MW

h

MWh

 

4

7000

28000

 

14

1500

21000

 

6

5500

33000

 

MWh

82000

 

Btu/MWh

3412000

 

Heat to buildings, million Btu/y

280000

67200

Heat to buildings, %

80.6

19.4

 

 

 

 

B20 supply, gal/y

 

 

720634

 

Wood Supply to New Wood Chip Plant for Truck Load Purposes

 

NOTE: I have chosen 7.6 million Btu/green ton, as that gives the highest tonnage. It is better to plan for too much tonnage than too little.

 

A tractor-trailer truck carries about 20 ton of woodchips.

Truckloads required would be about 16 per day for about 7.5 months of the year

About 2691 truckloads/y, or 52,600 ton of wood chips/y

Wood chip storage area would be about 20,000 cubic yards.

 

Truckloads of Wood Chips Required per Day: Truck loads required = 280,000 million Btu/y/ (20 ton x 7.6 million Btu/green ton x (6398 - 512)/8600, efficiency = 2691 truckloads/y

 

Woodchips are mostly supplied during much of the winter. On average, about 16 truckloads per day are required during 7.5 months, which would provide up to 20,000 cubic yards in storage. See table.

 

Table 4/Ton/Truckload

20

Heat value, million Btu/green ton

7.6

Efficiency, (6398 - 512)/8600

0.684

Heat to buildings from plant/truckload, million Btu

104.0

Truckloads/y

2691

Days/year

365

Delivery for 7.5 months of the year

0.625

Delivery days

228

Weekends + holidays

60

Delivery days

168

Truckloads/d

16

Burning Wood Produces Extremely Small Particles Harmful to Public Health

Dartmouth issued a Request for Proposal for the wood chip heating plant that specifies an electrostatic precipitator, ESP, for removing the toxic particulate matter, PM, from the plant exhaust gases.

 

That likely is a serious mistake, because ESPs are very poor at removing sub-micron particles, PM1.0 and smaller, which are most harmful to students, faculty and nearby residents. 

 

PM10 or smaller is inhalable and dangerous because such particles can penetrate deep into the lungs and are inhaled 24/7/365.

http://www.anapsid.org/cnd/mcs/fireban2.html

 

The removal of PM1.0 and smaller, is an extremely important consideration when attempting to control hazardous particles in the respirable range.

 

In general, the most difficult particles to remove are between 0.1 and 1.0 micron. Particles between 0.2 and 0.4 micron usually are hardest to remove and likely would be least removed.

https://www3.epa.gov/ttn/catc/dir1/fdespwpi.pdf

 

Wood Stoves are Big Polluters Compared With Gas and Fuel Oil Stoves

 

If 10 percent of building heating in Hanover would be by wood stoves, the PM and cancer-causing, polycyclic aromatic hydrocarbons, PAHs, would account for about 30 to 40 percent of all such compounds in Hanover’s ambient air.

 

The other ambient air PM and PAH would be from 1) other heating units that provide 90% of building heating in Hanover, and 2) other sources, such as traffic. See table.

 

Each gas or fuel oil stove emits about 50 to 100 times less PM and PAH than an EPA-certified wood stove.

Most buildings have older wood stoves that emit much more PM and PAH than EPA-certified wood stoves. See table and URLs.

 

https://slate.com/technology/2008/11/it-s-better-to-heat-your-home-...

https://www.bnl.gov/isd/documents/71376.pdf

 

NOTE: If in the future 20 percent of building heating in Hanover would be by wood stoves, the ambient air PM and PAH would increase by about 35%, if other sources remained the same.

 

NOTE: The dirty outdoor ambient air leaks into buildings, which results in the indoor air having about 70% of the dirtiness of the ambient air.

 

NOTE:

micron is a millionth of a meter.

mg/MJ is milligram/million joules.

 

Table 5/Household Appliance

Water boiler

Warm air furnace

Wood worse than

Particle size

 PM2.5 and smaller

 PM2.5 and smaller

Units

mg/MJ

mg/MJ

Times

Natural gas

0.016

0.011

1851.9

Ultra low sulfur diesel/fuel oil

0.025

0.060

588.2

Low sulfur diesel/fuel oil

0.490

0.510

50.0

No.2 fuel oil

1.320

2.100

14.6

Wood chip or pellet

25.000

25.000

1.0

 

Particle Size Distribution From Wood Chip Boiler

 

About 96% of PM in the raw (untreated) smoke from a wood chip boiler is PM10 or less, about 93% is PM2.5 or less, and 92% is PM 1.0 or less. Only about 4% is larger than PM10. See URL

https://www3.epa.gov/ttnchie1/efdocs/rwc_pm25.pdf

Particulate Loading in Flue Gases: Wood chip plants have particle loading in the flue gas of about 100 milligram/standard cubic meter. See note.

 

With ESPs, particle emissions less than 1 mg/std m3 can easily be obtained, i.e., at an efficiency of (100 - 1)/100 = 99.00%, or (150 - 1)/150 = 99.33%. However, almost all of the sub-micron particles are not removed. They are invisible, so the stack looks reassuringly “clean”, but, in fact, it 1s not, because much of the small, sub-micron particles were not removed.

 

NOTE: During testing the boiler would operate at 10 to 15% more air supply than is needed for complete combustion, and the flue gases would be hot. Corrections for 1) excess air and for 2) temperature and pressure are required to enable proper comparison of different operating conditions, fuels and boilers. Standard conditions (std) are defined as o C (32F) and absolute pressure of 10^5 pascal (1 bar).

https://en.wikipedia.org/wiki/Standard_conditions_for_temperature_a...

NOTE: The plant is kept at negative pressure, from combustion chamber to stack outlet, to prevent flue gas out leakage. Some air in leakage likely does occur, which would dilute the flue gases and make any EPA test readings appear less than in reality.

Particle Size Distribution in Flue Gases: It is important to know the particle size distribution in the flue gases to ensure proper selection of air pollution control systems. This article determined the particle size distribution in the flue gases of wood chip boilers.

 

It was found more than 80% (by weight) of the particles have diameters less than 1 micron and the mean particle diameter was less than 0.25 micron, i.e., half were larger and half were smaller than 0.25 micron. See figure 3 in URL

http://www.verenum.ch/Publikationen/Particle_Size_PH_TN1998.pdf

 

Table 6/Particle size

 Load, milligram/std m3

Less than 0.22 micron

 45

0.22

 21

0.35

 6

0.61

4

Greater than 7.22 micron

2

Total load

78

 

Fabric Filter Systems Much Preferred for Sub-Micron Particle Removal:

- Fabric filter systems remove PM9.5 and smaller at 99.84% efficiency, and PM0.36 and smaller at 99.98% efficiency. Table 1 on page 1145

  

- ESPs remove PM9.5 and smaller at 99.85% efficiency, and PM0.36 and smaller at about 50 - 70% efficiency. Figure 5 on page 1146

https://www.tandfonline.com/doi/pdf/10.1080/00022470.1974.10470025

 

-There are about 12 - 19 million PM10 particles per cubic centimeter and about 140 million PM0.6 particles/cm3 in the flue gases leaving wood chip boilers. See page 156

https://pdfs.semanticscholar.org/eb30/9818374e9236b689d6e66303e88a5...

 

Because, as stated above, more than 80% (by weight) of the particles are 1 micron and smaller, and the mean particle diameter is 0.25 micron, ESPs remove hardly any of the submicron particles, which are most harmful to health.

Collection Efficiency of ESP versus Multi-Cyclone/Fabric Filter Combo: The PM2.5 collection efficiency of a cyclone followed by a fabric filter system is at least 99.90%, including sub-micron particles. See table.

 

A cyclone system removes the larger particles, including the particles that are still hot, which protects the fabric filter system. If the cyclone system is followed by a fabric filter system, the combo is far superior to only an ESP. See URL

https://www.biomasscenter.org/images/stories/FSE_PM_Emissions.pdf

 

The below table includes collection efficiencies for PM 1.0 and smaller. That data was obtained from this URL.

https://www.tandfonline.com/doi/pdf/10.1080/00022470.1974.10470025

 

The data in the column “PM 1.0 and smaller” in below table was not provided by the BERC, likely to avoid drawing attention to the harmful sub-micron particles.

 

  The table below compares the collection efficiencies of common emissions control systems of wood chip fired plants.

 

- PM10 and smaller particles are inhalable and toxic.

- The sub-micron particles have a large total surface area. They penetrate more deeply into tissues and do more damage.

- An ESP is inadequate to remove the harmful sub-micron particles.

 

NOTE: The Biomass Energy Resource Center (BERC) is a division of Vermont Energy Investment Corporation (VEIC), a quasi-state entity that also includes Efficiency Vermont, which is financed by electric ratepayers at about $65 million per year.

 

BERC works to advance the use of community-scale biomass energy throughout North America and beyond by providing technical consulting services, biomass energy program design and delivery, and education and outreach on benefits and best practices.

 

Table 7/Removal efficiency

PM 10 and smaller

PM 2.5 and smaller

PM 1.0 and smaller

%

%

%

Single Cyclone

50

5

0

Multi-Cyclone

75

10

0

Core Separator

29 to 56

72 to 94

0

Multi-cyclone with fabric filter

99.84

99.90

99.95

Electrostatic Precipitator (ESP)

99

96

50 - 70

APPENDIX 1

EPA Particulate Matter Standard

The EPA periodically issues and revises its standards regarding particulate matter in flue gases. The EPA PM standards were initially issued in 1997.

 

- In December 2012, the EPA revised the primary annual PM2.5 standard from 15 micrograms per cubic meter (μg/m3) to 12 μg/m3 for the protection of public health.

- During the 2012 review of the standards, the EPA retained the 1997 secondary annual PM2.5 standard of 15 μg/m3 for the protection of public welfare.  

- The 2006 24-hour primary PM2.5 standard was set at 35 μg/m3, and was not revised in 2012.

https://www.epa.gov/sites/production/files/2016-07/documents/fact-s...

- The EPA may have to issue a PM1.0 standard in the near future, because as biomass burning is increasing, more people would be exposed, plus there is increasing evidence sub-micron particles have a significantly greater adverse impact on health than was thought. BTW, the particulates of tobacco smoke consist almost entirely of sub-micron particles.

 

EPA PM2.5 and Peace of Mind: The PM2.5 standard is supposed to give “peace of mind” to people, because there appears to be nothing coming out of the stack, a so-called “clear stack”.

 

In fact, the PM2.5 standard, issued in 1997, is grossly inadequate, because whatever is measured by means of standard EPA stack testing methods tells nothing about the number, size, weight and chemical composition of the invisible submicron particles, which are the most harmful to health.

 

PM10 and PM2.5: Two types of PM are shown: PM10 (particles 10 microns and smaller) and PM2.5 (particles 2.5 microns and smaller), the latter of which are of greatest concern relative to impacts on public health. See URL

https://www.epa.gov/pm-pollution/particulate-matter-pm-basics

 

PM10: Inhalable particles, with diameters generally 10 micrometers and smaller

PM2.5: Fine inhalable particles, with diameters generally 2.5 micrometers and smaller

 

- How small is 2.5 micrometers?

The average human hair is about 70 micrometers in diameter, making it about 30 times larger than a PM2.5 particle.

- How small is 0.5 micrometers?

A hair diameter is about 70/0.50 = 140 times larger than a PM 0.5 particle

 

Sub-micron particles stay in the air a long time, become widely dispersed before settling down, i.e., plenty of time to be ingested by humans 24/7/365.

 

APPENDIX 2

Sequestering Combustion CO2 From Wood Chip Burning Plants Takes Decades

 

Here is some information for those who have been led to believe, or persuaded themselves to believe, wood burning is environmentally friendly.

 

Forests have aboveground and belowground new growth, which absorbs CO2 from the air and carbon, C, from the soil. Removing live trees, low-grade and high-grade, reduces CO2 absorption. In Vermont, about 50% of tree removals is used for high-grade purposes (the C stays sequestered, until some of it is burned); and about 50% is used mostly for burning (the C becomes CO2 and is released to the atmosphere), and a small quantity is used for pulp/paper mills (the C stays sequestered, unless some of it is burned).

 

Wood burning power plants (McNeil, Ryegate in Vermont) emit about 4 times the combustion CO2/kWh of high-efficiency gas turbine power plant.

 

NOTE: The combustion CO2 of wood burning would be reabsorbed by new tree growth, if:

 

1) Logged forests would have the same acreage (they likely would not)

2) Forests would not further fragmented by roads or developed (they likely would be)

3) Forest CO2 sequestering capability, Mt/acre/y, remains the same (it could be less). See note

 

NOTE: Regarding the time period for sequestering the combustion CO2:

 

- 40 years is a US average, as promulgated by EPA. See Note.

- 80 to 100 years in northern climates with short growing seasons, such as northern Vermont and Maine. 

- 40 to 50 years in moderate climates with longer growing seasons, such as New Jersey and North Carolina

- 25 years between harvests of planted, fertilized, and culled forests of fast-growing pines in Georgia. 

https://www.pfpi.net/wp-content/uploads/2011/04/PFPI-biomass-carbon...

 

NOTE: On an A to Z basis, there would be about 10% of additional CO2 that has nothing to do with combustion, in case of wood chips, or about 15%, in case of wood pellets. This includes non-wood-burning CO2, such as from:

 

- Fuel used for managing wood lots, logging, chipping/pelletizing and transport,

- Energy to run the plant,

- Energy for decommissioning and reuse/landfill of the plant,

- Embodied energy in the A to Z infrastructures

Piling up the CO2 Year After Year

Re-growing trees would sequester the combustion CO2 of Year 1 of plant operation over about 80 to 100 years, in New England.

 

The CO2 of Years 2, 3, 4 to Year 40 would be added to the CO2 of Year 1, and be sequestered in a similar manner, except shifted forward by a year.

 

In Year 40, there would be 40 layers of CO2 and 40 forest areas in various stages of regrowth, as a result of cutting trees for burning.

 

Year 40 is assumed to be the last year of plant operation. It is likely that plant would be replaced to repeat the cycle.

 

During Year 41 through 80, there would be 41 to 80 layers of CO2 and 41 to 80 forest areas in various stages of regrowth, as a result of cutting trees for burning.

APPENDIX 3

Biodiesel CO2 Emissions: In case of biodiesel, B100:

 

- The combustion CO2eq emissions are 20.829 lb/gal (or 1000000/128490 x 20.829 = 162 lb/million Btu), and

- The upstream CO2eq emissions are 10.524 lb/gal (or 1000000/128490 x 10.524 = 82 lb/1000000 Btu).

- Some people do not count the combustion emissions, because biodiesel is “renewable”, but upstream emissions should be counted. See URL.

http://www.windtaskforce.org/profiles/blogs/replacing-gasoline-and-...

US Biodiesel Production is Very Small: US B100 consumption was 1985 million gallon, of which US production was 1596 million gallons in 2017.

 

US total “diesel” consumption (a blend of B100 and petro-diesel) was 45,833 million gallon, per EIA.

Replacing all petro-diesel with B100 would require 49,479 million gallon of B100, from 651 million acres planted with soybeans.

US total cropland, all uses, is about 334 million acres.

 

Table 8/Source

Million gallon

Soy oil, from 10.857 million acres

826

All other sources

 770

Imports

 301

From inventory

 81

APPENDIX 4

Deleted

 

APPENDIX 5

Low Temperature or High Temperature Hot Water Distribution to Buildings

 

Low temp hot water heating of buildings is feasible with adequately specified heating units in each room. It would be prudent to implement major upgrades of the buildings to reduce their Btu/sq ft/y for heating, cooling, and electricity.

Having high temperate hot water, HTHW, a la University of Vermont, for distribution provides flexibility, because it allows for: 

 

1) Lowering the HTHW temperature to LTHW within each building for building heating, and allows for having

2) HTHW for distributed, 2-stage absorption chillers for building cooling, and allows for having

3) The plant to be located further from buildings.

APPENDIX 6

Many people parrot the mantras “burning wood chips is renewable”, and "we are taking only about 50% of the new tree growth". They likely do not have a clue what that really means. So here is an explanation.

 

Each year, there would be hundreds of scars on the forest landscape where logging took place with big machinery to feed wood chips to the Dartmouth heating plant.

 

Some of those scars would be due to clear-cuts, the worst kind of logging, because it kills the belowground forest biomass, i.e., nature has no use for it, so it gets rid of it. That belowground biomass would have to rebuild itself as part of tree regrowth over decades.

 

Such killing of the belowground forest biomass, and consequential erosion of topsoil, took place on a NE-wide scale in the 1800s. NE soil and forests still have not recovered from that devastation. The big trees are gone and will not come back, likely because the damaged soil would not be able support them.

 

Taking wood from the forest for decades ultimately depletes the soil, which was already damaged due to clear cutting in the 1800s and due to acid rain since the 1950s.

 

We see mostly spindly trees that often become sickly and do not live long.

We see a gradual takeover of the forest by acid loving trees, such as white pines.

It would be better to chip the wood and spread it on the forest floor for more rapid nutrition, and to provide about 1 to 2 ton of dolomite lime per acre to reduce the acidy of the soil.

In sum, it appears the practice of wood burning has various consequential damages, which in addition to other human encroachments, have become a near permanent part of modern lifestyles, all to the detriment of forest health.

APPENDIX 7

Clearcutting Damages Forest Floors and Causes Decay of Belowground Biomass

 

Clearcutting destroys the understory flora, damages the forest floor and the belowground biomass. As the belowground biomass is no longer needed it decays. The resulting decay CO2 would be in excess of the CO2 absorbed by biomass regrowth on the clearcut areas for about 15 years. After that, it would take up to 20 years until the biomass regrowth on the clearcut areas would have absorbed the excess CO2 of the first 15 years. The about 35 years is called the C-neutrality period.

 

Only after the C-neutrality period would any biomass combustion CO2 (emitted during year 1) be absorbed. The new biomass growth would absorb that CO2 only as fast as it needs to, i.e., at a fast rate up to year 40 to 50, and slower rates thereafter. The biomass combustion CO2 of year 2, and of each subsequent year, each have to wait about 35 years, etc.

 

In northern climates, with 4-month growing periods, the whole absorption process would take about 80 to 100 years to completion. At the end of that period one can claim wood burning as having been “renewable” regarding the biomass combustion CO2, i.e., about 115 to 135 years after burning the wood in year 1.

 

Any CO2 of the A to Z process (upstream, plant operation and downstream), other than biomass combustion CO2, should be treated as any other CO2. See URL.

http://www.windtaskforce.org/profiles/blogs/co2-emissions-from-logg...

 

NOTE: Prior to any clearcutting, the clearcut areas were absorbing and storing CO2 at a rate of about 1.0 metric ton per acre per year, for free.

 

The Vermont Biomass Energy Research Center

 

BERC, a pro-logging industry consultant, which is part of the pro-renewable Vermont Energy Investment Corporation, VEIC, invented a unique method of calculated CO2 from wood burning plants that has no parallel anywhere else, and is likely not used anywhere else, except in Vermont. It completely ignores the above 35-year C-neutrally period, and the slow absorption of combustion CO2 over about 80 to 100 years thereafter, and it ignores the year-after-year CO2 build-up in the atmosphere while the CO2 is slowly being absorbed by the regrowth on the harvested areas.

 

The BERC-invented 82% CO2 reduction must give great comfort to wood burning proponents, because BERC purposely forgot to add "over about 80 - 100 years after the C-neutrality period". Here is a quote:

 

“While the recommended carbon emission factor of 29.58 pounds per million Btu is far from the historic “carbon neutral” stance, when compared to the carbon emissions (165.5 pounds per million Btu) from burning heating oil, it represents an 82% reduction in CO2 emissions’.

https://www.biomasscenter.org/pdfs/veic-carbon-emission-and-modern-...

 

APPENDIX 8

Old Growth Forests Store at Least 2 Times the Carbon of 60-y-old Forests

Old-growth forests store more carbon than younger forests, because they had more time to grow larger trees and develop a complex forest floor. The following chart shows the carbon storage within the components of a young forest and ancient forest ecosystem. Forest floors in old-growth forests contain significantly more carbon than forest floors of harvested forests (Lecomte et al. 2006; Fredeen et al. 2005; Harmon et al. 1990).

https://www.biologicaldiversity.org/programs/climate_law_institute/...

 

Table 9/Carbon storage

60-y-old forest

Old-growth forest

metric ton C

metric ton C

Foliage

5.5

6.2-7.0

Branches

7.0

26.3

Boles (wood and bark)

145

323.0

Roots (fine)

5.6

5.6

Woody debris and forest floor

10.9 - 26.1

123.0

Total

203 - 218

555 -556

 

APPENDIX 9

Carbon Content of Wood: The carbon contents in heartwood of softwood and hardwood species were determined. C in kiln-dried hardwood species ranged from 46.27% to 49.97%, and in conifers from 47.21% to 55.2%. Heartwood is the older harder non-living central wood of trees that is usually darker, denser, less permeable, and more durable than the surrounding sapwood.

https://www.sciencedirect.com/science/article/pii/S0961953403000333

 

The average higher heating value, HHV, of the more resinous softwoods is about 9,000 Btu/lb of dry trunk wood, and for the less resinous hardwoods about 8,300 Btu/lb of dry trunk wood. The EPA selected an average value of 8600 Btu/lb of dry trunk wood.

 

Wood Chips for Burning: Wood chips usually are made from whole trees that are fed into very large chippers. It is a noisy sight to behold. A large crane grabs an 18-inch diameter tree, feeds it horizontally into the big hopper, and within about a minute the entire tree has become wood chips that are blown into a 40 ft trailer!!! The trees are low quality trees, and often are misshapen, sickly and dead trees.

 

Whole tree wood chips consist of about 50% carbon and about 6% hydrogen (by weight) and have a typical heat content of 4785 Btu/lb at 44% moisture content, or 4785 / (1 - 0.44) = 8545 Btu/lb, HHV, dry. See URLs

 

CO2 emissions of wood, per EPA, are (1000000/8600, HHV) x 0.50, C fraction x 44/12, mol. wt. ratio = 213.18 lb/million Btu.

 

CO2 emissions of wood chips, per BERC, are (1000000/8545, HHV) x 0.50, C fraction x 44/12, mol. wt. ratio) = 214.6 lb/million Btu

 

https://phyllis.nl/Browse/Standard/ECN-Phyllis##2718

https://www.biomasscenter.org/images/stories/Woodchip_Heating_Fuel_...

https://ucanr.edu/sites/swet/files/274491.pdf

 

NOTE:

The 44/12-molecular weight ratio is calculated as follows:

The combustion equation is C + O2 --> CO2. 

Molecular weight of CO2 = 12 lb C + 32 lb O2 —> 44 lb, or

12/12 ton C + 32/12 ton O2 —> 44/12 ton CO2

https://mha-net.org/docs/v8n2/docs/WDBASICS.pdf

 

APPENDIX 10

Higher and Lower Heating Values: The HHV is determined with a “bomb” calorimeter in a laboratory. Fuel is fed in, at say 60F, and combusted with pure oxygen until combustion is complete. Heat is extracted from the products of combustion to reduce their temperature to 60F. The water vapor due to combustion of hydrogen in the fuel (2 H2 + O2 --> 2 H2O) is condensed and cooled to 60F. See note and URLs.

 

https://www.ddscalorimeters.com/why-high-pressure-oxygen-is-used-in...

https://en.wikipedia.org/wiki/Calorimeter

 

LHV = HHV – energy from condensed water vapor from hydrogen combustion.

LHV of a fuel should be used when performing calculations to determine the efficiency of a heating plant, as shown Appendix 5.

 

HHV is one of the properties of a fuel, as sold in the marketplace.

 

However, if a fuel is combusted, the temperature of the flue gases of boilers and furnaces is very rarely reduced to condense the water vapor, because that would rapidly corrode the ductwork to the precipitator and steel plates of the precipitator that removes most of the particulates from the flue gases, and the ductwork to the chimney and steel liner of the chimney.

 

The “energy from condensed water vapor from hydrogen combustion” goes up the chimney.

The larger the hydrogen weight percent in the fuel, the greater the water vapor weight percent in the flue gases.

 

NOTE: In case of real-world conditions, the flue gas has water vapor due to:

 

1) Combustion of hydrogen in the fuel

2) Humidity of the combustion air and in excess air

3) Water in the wood chips

 

Items 2 and 3 have nothing to do with the definition of LHV. However, some people subtract all three items from HHV to obtain their LHV.

NOTE: Flue gases often contain acidic gases that condense at higher temperatures than water vapor. Any heat recovery from flue gases, such as for drying wood chips, must maintain the flue gases above the condensing point of any acidic gas, usually about 270F - 300F.

NOTE: Households often have wall-hung, gas or propane fired, condensing furnaces, such as by Viessmann and Buderus (both made in Germany).

 

- During a fall or spring day, the circulating hot water for space heating is heated to about 130F (the furnace is in condensing mode, about 95% efficient).

- During a cold winter day, the circulating water is heated to about 170F (the furnace is not in condensing mode, about 85% efficient).

- If a house is highly sealed and highly insulated and has suitable baseboard radiators, the circulating water would be about 130F, or less, most of the heating season, and the furnace would be in condensing mode most of the season.

 

NOTE:

HHVs and LHVs of Other Fuels

- E10, usually called gasoline, also called gasohol, is a blend of 90% gasoline and 10% E100.

- B100 is 100% biodiesel

- B20 is a blend of 80% petroleum-diesel and 20% B100

See table 3 and URL.

 

https://h2tools.org/hyarc/calculator-tools/lower-and-higher-heating...

http://nhcleancities.org/2017/04/can-compare-energy-content-alterna...

https://afdc.energy.gov/fuels/fuel_comparison_chart.pdf ;

 

Table 10

Ethanol

Gasoline

E10 (90/10)

Petro-diesel, LS

B100

B20 (80/20)

NG

LNG

 

 

 

 

 

 

 

Btu/lb

Btu/lb

HHV, Btu/gal

84530

124340

120359

138490

127960

136384

22453

23735

LHV, Btu/gal

76330

116090

112114

128488

119550

126700

20267

20908

 

Nm3 = normal cubic meter under normal conditions of 0°C and 1 atmosphere.

 

To convert Nm3 to a cubic foot of gas, multiply by 38.04.

Therefore, 1,000 Nm3/day = 38,040 cf/day.

 

APPENDIX 11

Manufacturer Efficiencies vs Real World Efficiencies: When manufacturers test their wood chip boilers, they use a carefully selected sample of dry wood chips. They determine the heat content, Btu/lb, of the wood chips with a “bomb” calorimeter in a laboratory. They operate their boilers at high output in steady output mode. They continuously monitor:

 

Inlet conditions; fuel input and its temperature, and excess air flow and its temperature.

Outlet conditions; flue gas temperature and CO content; hot water flow, and hot water in and out temperatures.

 

In this manner, they can calculate the high thermal efficiencies stated in brochures.

The efficiencies in the real world are significantly less, as shown in below table.

 

Efficiency of a Heating Plant; loss method

Information extracted from this URL

https://mha-net.org/docs/v8n2/docs/WDBASICS.pdf

 

Heating value of wood

 

H2 + ½ O2 --> H2O, plus 62,000 Btu/lb

C + O2 --> CO2, plus 14,600 Btu/lb

1 lb wood is 49% C, 0.48 x 14,600 = 7,008 Btu/lb

1 lb wood is 6% H, 0.06 x 62,000 = 3,720 Btu/b

1 lb wood = 10,728 Btu, theoretical

The generally accepted HHV is 8600 Btu/lb of dry wood

 

1) Heat Loss due to water vapor produced by burning hydrogen

 

2 lb H2 + 16 lb O2 —> 18 lb H2O

Carbon in 100 lb of dry wood is 49 lb

Hydrogen in 100 lb of dry wood is 6 lb

0.06 lb H2 + 0.48 lb O2 —> 0.54 lb H2O

Heat of vaporization is 1058.2 Btu/lb water

Evaporation loss = 0.54 x 1058.2 = 570 Btu/lb

LHV = 8600 - 570 = 8030 Btu/lb dry wood

 

2) Heat Loss due to moisture content in wood

 

Moisture content, mc, dry weight basis

mc dry basis, % = (Weight wet - Weight dry)/Weight dry x 100

mc dry basis, % = (115 w - 100 d)/100 d x 100 = 15%

 

Moisture content, mc, wet weight basis

mc wet basis = (Weight wet - Weight dry)/Weight wet x 100

mc wet basis = (115 w - 100 d)/115 w x 100 = 13%

 

or

Wood, dry = (1 - 0.15) x 100 lb = 85 lb; water is 100 - 85 = 15 lb

Wood, wet = 1/(1 + 0.15) x 100 lb = 87 lb, water is 100 - 87 = 13 lb

 

See equilibrium moisture content graph and table in URL

At 80% humidity, mc is 15%

Assume wood chips are pre-dried with heat recovered from flue gases to 15% mc

Heat available = 0.85 x 8030 = 6845 Btu lb, as fed to boiler

 

NOTE: If 1000 lb of grain is harvested at 25% mc, and dried to 14% mc, what is the final weight of the dried grain?

Final weight of grain = 1000* (100 - 25)/(100 - 14) = 872 lb at 14 % mc

 

3) Heat loss due excess combustion air, assumed at 30%

 

1 lb C requires 11.52 lb of air, or 0.49 lb C requires 5.65 lb of air

1 lb of H2 requires 34.56 lb of air, or 0.06 lb of H2 requires 2.07 lb of air

1 lb of wood requires 5.65 + 2.07 = 7.72 lb of air

Excess air is 0.3 x 7.72 = 2.32 lb

Temp difference = 270F, downstream of heat recovery unit - 70F, fuel feed in = 200F

Air specific heat is 0.24 Btu/lb

Heat loss due to excess air is 2.32 x 0.24 x 200 F = 111 Btu/lb of wood. See note

 

NOTE: If excess air were 100%, loss would be 370 Btu/lb of wood.

 

4) Heat loss due to boiler/ductwork air in leakage, assumed at 34 Btu/lb of wood.

Table 11/Efficiency %, LHV basis

 Btu/lb, dry

Theoretical, but essentially impossible total, see URL

 10728

Generally accepted HHV, per EPA

8600

Losses

1) Reduced due to water vapor produced by burning hydrogen, LHV = HHV - 570 

8030

2) Reduced due to moisture content - see table in URL and make your choice, in this case

6845

3) Reduced due to excess air - see discussion and make your choice

111

4) Reduced due to air in leakage of boiler and ductwork

34

6700

Other losses

5) Boiler jacket, 2% of 6700

134

6) Boiler room piping and equipment, 1% of 6700

67

7) Combustibles in flue gases, 0.5% of 6700

34

8) Combustibles in bottom ash, 1% of 6700

67

Heat to hot water distribution system

6398

Boiler efficiency, %, 100 x 6398/8030; steady conditions

79.7

Plant self-use; electrical energy and vehicle fuel input, 6% of 8600

516

Plant energy input = 8030 + 516

8546

Plant efficiency, %, 100 x 6398/8546*

74.9

Distribution system loss due to pumping and heat transfer = 8% of 6398

512

Plant + Distr. System energy input = 8546 + 512

9058

Heating system efficiency, %, 100 x 6398/9058

70.6

Wood chip harvesting, chipping, transport = 5% of 8600

430

A to Z energy input = 9058 + 430

9488

A to Z efficiency, %, 100 x 6398/9488^

67.4

 

strong>Annual average boiler efficiency likely would be about 70%, which corresponds with literature values.

* Annual average plant efficiency likely would be about 65%

^ Annual average heating system efficiency would be about 60%

> Annual average A to Z efficiency would be about 57%

 

Embedded and decommissioning/landfill energy are ignored.

APPENDIX 12

Closing Down Wood Burning Power Plants

 

It would be far better for New Hampshire, Maine and Vermont to shut down wood burning power plants, as time is of the essence regarding “climate change”, according to some people. See table 5 and URL.

 

- In Vermont, utilities are forced to buy wood electricity at about 10 c/kWh, as part of the Vermont Standard Offer program, and as required by the Vermont Renewable Portfolio Standard program.

 

- In New Hampshire a law was passed in 2018 to subsidize money-losing NH wood burning power plants. The plants need to be base-loaded to maximize production and need to sell at about 9 - 10 c/kWh to be viable. The subsidy would impose an extra cost on ratepayers of about $25 million/y. Implementing the law is held up in various court cases for environmental reasons.

 

- The wholesale prices of the NE grid averaged about 5 c/kWh since 2008, courtesy of abundant, domestic, near-zero-subsidized, clean-burning, low-CO2 gas at about 5 c/kWh, and near-zero-subsidized, near-zero-CO2 nuclear at 4.5 - 5 c/kWh.

http://www.windtaskforce.org/profiles/blogs/furnaces-for-heating-an...

 

Table 12/Fuel

 lb CO2/million Btu

 Plant efficiency, %

 lb CO2/MWh

CO2 Ratio

Wood chip; McNeal/Ryegate*

213

25

2907

4.0

Wood chip; Denmark

213

30

2423

3.3

Hard coal

206

41

1712

2.4

No. 2 fuel oil

161

35

1572

2.2

Natural gas, CCGT*

117

55

726

1.0

*

Plus upstream CO2 (logging, chipping, transport, etc.) of about 5 to 10%, if burning wood chips

Plus upstream CO2 (logging, chipping/pelletizing, transport, etc.) of about 10 to 15%, if burning wood pellets

CCGT = Combined-cycle, gas turbine plant

APPENDIX 13

Here is my rational explanation regarding traditional temperature prediction programs “tracking high”.

 

I work for an RE organization and am in charge of the temperature prediction computer program that helps keep a steady RE funding flow going.

I could be working at Dartmouth or UVM or MIT, or any entity dependent on an RE funding flow.

The flows likely would be from entities MAKING BIG BUCKS BY PLAYING THE RE ANGLE, like Warren Buffett.

 

My job security bias would be to adjust early data to produce low temperatures and later data to produce high temperatures.

I would use clever dampers and other tricks to make the program “behave”, with suitable squiggles to account for el Niño’s, etc.

Also I do not want to stick out by being too low or too high.

The average graph of all temperature prediction programs, in bold, is helpful for guidance, as it is prominently displayed among the others.

Everyone in the organization would know me as one of them, a team player.

Hence, about 30 or so temperature prediction programs behave in similar ways, if plotted on the same graph.

 

Comes along the graph, based on 40-y satellite data, which requires no adjustments at the low end or the high end.

It has plenty of ACCURATE data; no need to fill in any data in the blanks or make any adjustments.

Its temperature prediction SLOPE is about 50% of ALL THE OTHERS.

 

If I were a scientist, that alone would give me a HUGE pause.

However, I am merely an employee, good with numbers and a family to support.

Make waves? Not me.

 

If the above is not rational enough, here is another.

At Dartmouth College, Ivy League, the higher ups have decided burning trees is good.

Well, better than burning fossil fuels any way, which is not saying much.

By now all Dartmouth employees mouth in unison “burning trees is good, burning fossil fuels is bad”.

Job security is guaranteed for all.

 

But what about those pesky ground source heat pumps OTHER universities are using for their ENTIRE campuses.

Oh, we looked at that and THEY are MUCH too expensive.

For now, i.e., ONLY FOR THIRTYFIVE YEARS, we decided Dartmouth will be burning trees.

After that who knows. The world as we know it may have ended.

Dartmouth, with tens of $BILLIONS in endowments, could not possibly afford those ground source heat pumps.

 

Example 1: There are around two million single-family houses in Sweden, and approximately 20-25% of these houses are heated with ground source heat pumps, GSHPs (2015 status)

They work great no matter the outside temperature, because the ground temperature always is about 55F, when outside it is about 0F in winter, i.e., air source heat pumps, much touted by Vermont and Maine, would be useless.

https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/01021.pdf

http://www.windtaskforce.org/profiles/blogs/fact-checking-regarding...

http://www.windtaskforce.org/profiles/blogs/heat-pumps-oversold-by-...

Example 2: My cousin lives on the ninth floor of a 12-story modern, condo building in Maassluis, the Netherlands. The building is part of a housing complex of 20 buildings entirely provided with heating, cooling and domestic hot water from ground source heat pumps already for more than 35 years.

 

The coils are under the parking lots. After parting your car, click a fob and the lobby lights go on and the elevator door opens, get on and, without pressing any buttons, it takes you to the ninth floor. Press another fob, the front door unlocks and pre-programmed lights turn on.

 

In the Netherlands, GSHP systems are old hat, routine BAU.

 

And so it goes, said Kurt Vonnegut, RIP.

APPENDIX 14

The CO2 absorption, a.k.a., sequestering, for all of Vermont forestland, 4,488,000 acres in 2015, was calculated at about 4.38 million metric ton/y, or about 0.976 metric ton/acre, by using computer programs developed by the US Forest Service.

 

Vermont’s net CO2 emissions were 10.0 - 4.38 = 5.62 million metric ton in 2015, or 8.992 metric ton per person, near the lowest in the US. Vermont has many problems, but CO2 emission is certainly not one of them. It should be near the bottom of the list of priorities. However, fear mongering to induce GW hysteria, hyped by folks seeking overly generous federal and state subsidies, caused self-serving politicians to place CO2 reduction near the top. See URLs.

 

https://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/The_For...

https://www.fs.fed.us/nrs/pubs/ru/ru_fs119.pdf

APPENDIX 15

Conversion Factor for Carbon Sequestered in One Year by 1 Acre of Average U.S. Forest

0.23 metric ton C/acre/year* x (44 units CO2/12 units C) = 0.85 metric ton CO2 sequestered annually by one acre of average U.S. forest.

Please note that this is an estimate for “average” U.S. forests in 2016; i.e., for U.S. forests as a whole in 2016.

Significant geographical variations underlie the national estimates, and the values calculated here might not be representative of individual regions, states, or changes in the species composition of additional acres of forest.

https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculato...

 

NOTE: Disturbed, fragmented, less than healthy forests, as in most of New England, sequester about 1.0 metric ton of CO2 per acre per year, due to:

 

1) Acid rain and pollution from Midwest power plants, etc.,

2) Various encroachments, and

3) Colder climate and short growing season.

 

The Vermont and Maine Environmental Departments claim 0.976 and 1.10 metric ton/acre/year, respectively. See URLs.

 

https://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/The_For...

https://www.fs.fed.us/nrs/pubs/ru/ru_fs119.pdf

 

https://fsht.files.wordpress.com/2019/04/maine-forest-carbon-estima...

http://www.forestecologynetwork.org/climate_change/sequestration_fa...

APPENDIX 16

Flue Gas Cleaning of Wood Chip Boilers: The Middlebury College wood chip plant has a cyclone separator system followed by a fabric filter system to reduce pollutants in flue gases.

 

The flue gases pass through the cyclone separator to remove the larger particles, 5 micrometer and greater. The larger particles may be hot and could damage the fabric filter system.

 

After the cyclone separator, the flue gases enter the fabric filter system to remove particles smaller than 5 micrometers, including a high percentage of particles smaller than 1 micrometer.

 

The fabric filter system is factory rated to remove 99.7% of particulates (by weight), so most of what one sees exiting the smoke stack is condensed water vapor. That may appear reassuring to lay people, but it is not to people who know the real-world facts.

 

The 0.3% of the total particulate weight consists of particles smaller than 1 micrometer. There are about 50 to 150 million of such particles per cubic centimeter of flue gas after passing through the fabric filter system. Those toxic particles do not weigh much, but penetrate deeply into lung tissues and are absorbed by the blood of residents near the plant. The flue gases stay near the ground during no-wind conditions during the heating season.

 

If the fabric filter system had a slight defect, the efficiency could be, say 99%, or less, i.e., the 0.3% would become 1%, 3 times greater. The appearance of the flue gases from the chimney would remain unchanged. Plant operators would not know if there had been a change, unless there was continuous flue gas monitoring upstream and downstream of the fabric filter system to calculate the efficiency.

 

NOTE: The removal efficiency of particles smaller than 1.5 micrometer of precipitators is less than of fabric filter systems. A precipitator may have and efficiency of 99.5%, but the 0.5% passing through mostly would consist of particles smaller than 1.5 micrometer.

APPENDIX 17

The release to the environment of unhealthy ash from burning wood chips is a necessary evil to have hot water for the space heating of buildings.

 

If ash release, lb/million Btu, is based on boiler heat output, which heats the hot water, it would enable rational comparison of various approaches to obtain the desired results, i.e., warm buildings.

 

Some of these approaches, such as increased sealing and increased insulation of the buildings, likely would be more efficient and environmentally desirable than burning wood chips.

 

The Middlebury College cyclonic separator/fabric filter combo would need to have an annual average efficiency of 97.6% to the achieve the 0.017 lb/million Btu, based on boiler heat input. See URL

http://media.freeola.com/other/17221/futherdetailsoncolleges.pdf

 

However, due to various losses, 1 through 8 in table 11, that do not contribute anything to heating hot water, only 6398 Btu/lb, dry, would be available to heat the hot water.

 

Table 13 shows:

 

- The flyash before pollution control combo would be 0.938 lb/million Btu, based on boiler heat output.

- The flyash after pollution control combo would be 0.023 lb/million Btu, based on boiler output.

 

Total flyash from the boiler would be about 200 x 0.3 = 60 ton/y, of which about 60 x (1 - 0.976) = 1.462 ton/y would leave the chimney as particles smaller than 1 micrometer.

 

NOTE: The Middlebury College air pollution control systems have a manufacturer rated efficiency of about 99.7%, per Middlebury College website.

 

Table 13/Middlebury College Biomass Plant

Heat input basis

Heat output basis

Wood chip consumption

US ton/y, wet

20000

20000

Water

%, as harvested

50

50

Wood chip consumption

US ton/y, dry

10000

10000

Ash

%, dry

2

2

Ash

US ton/y

200

200

Ash

lb/y

400000

400000

Wood

Btu/lb, dry

8600

8600

Heat input

million Btu/y

172000

172000

Heat output, based on 6398 Btu/lb

million Btu/y

127960

127960

Boiler Efficiency

%

74.4

74.4

Ash

lb/million Btu

2.326

3.126

Bottom ash, assumed

%

70

70

Flyash, assumed

%

30

30

Flyash before removal

lb/million Btu

0.698

0.938

Flyash after removal, see URL

lb/million Btu

0.017

0.023

Removal efficiency, annual average

%

97.6

97.6

Flyash leaving chimney

ton/y

1.462

1.462

Views: 490

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Comment by Frank J. Heller, MPA on June 3, 2019 at 12:37pm

Is there a breakdown of heat produced, when, where and how much over time and the electricity produced? Detroit(?) has a W2E plant which distributes heat as well after steam is used to generate electricity. Apparently, waste to energy plants are closing for a variety of reasons. But what will replace them?

Comment by Willem Post on June 2, 2019 at 2:34pm

Frank 

Biodiesel, B100, has a lot of upstream/A to Z CO2; about 45.24% of combustion CO2.

Even if combustion CO2 were not counted "because it is renewable", there still would be a lot of CO2 associated with the biodiesel part of the central plant, which provides 24% of the heating.

Burning wood chips has about 15% of upstream/A to Z CO2.

Even if combustion CO2 were not counted "because it is renewable", there still would be a lot of CO2 associated with the wood chip part of the central plant, which provides 76% of the heating.

There will be hundreds of scars on the forest landscape where logging took place to feed wood chips to the new plant.

Some of those scars will be clearcuts, the worst kind of logging, as it kills the forest biomass below the ground, which would have to rebuild itself. That is what happened in the 1800s.

NE forests still have not recovered from that devastation. We mostly see spindly trees that become sickly and do not live long, and a takeover of the forest by acid loving trees, such as white pines.

Taking wood from the forest ultimately will deplete the soil, which was already damaged due to clear cutting in the 1800s and due to acid rain since the 1950s.

There is absolutely nothing about wood burning that is renewable, as various damages are near permanent.

Comment by Frank J. Heller, MPA on June 2, 2019 at 10:14am

Studied 'green waste' hauled to town dumps for disposal and found quite a bit of it...problem is aggregating it and chipping it--just another approach.

Surprised they didn't consider natural gas as an energy source combines with methane from anaerobic digesters. 

Dartmouth was one of the leaders in solar powered car and plane development,so I'm surprised they settled on wood chips and deforestation.

Hannah Pingree on the Maine expedited wind law

Hannah Pingree - Director of Maine's Office of Innovation and the Future

"Once the committee passed the wind energy bill on to the full House and Senate, lawmakers there didn’t even debate it. They passed it unanimously and with no discussion. House Majority Leader Hannah Pingree, a Democrat from North Haven, says legislators probably didn’t know how many turbines would be constructed in Maine."

https://pinetreewatch.org/wind-power-bandwagon-hits-bumps-in-the-road-3/

 

Maine as Third World Country:

CMP Transmission Rate Skyrockets 19.6% Due to Wind Power

 

Click here to read how the Maine ratepayer has been sold down the river by the Angus King cabal.

Maine Center For Public Interest Reporting – Three Part Series: A CRITICAL LOOK AT MAINE’S WIND ACT

******** IF LINKS BELOW DON'T WORK, GOOGLE THEM*********

(excerpts) From Part 1 – On Maine’s Wind Law “Once the committee passed the wind energy bill on to the full House and Senate, lawmakers there didn’t even debate it. They passed it unanimously and with no discussion. House Majority Leader Hannah Pingree, a Democrat from North Haven, says legislators probably didn’t know how many turbines would be constructed in Maine if the law’s goals were met." . – Maine Center for Public Interest Reporting, August 2010 https://www.pinetreewatchdog.org/wind-power-bandwagon-hits-bumps-in-the-road-3/From Part 2 – On Wind and Oil Yet using wind energy doesn’t lower dependence on imported foreign oil. That’s because the majority of imported oil in Maine is used for heating and transportation. And switching our dependence from foreign oil to Maine-produced electricity isn’t likely to happen very soon, says Bartlett. “Right now, people can’t switch to electric cars and heating – if they did, we’d be in trouble.” So was one of the fundamental premises of the task force false, or at least misleading?" https://www.pinetreewatchdog.org/wind-swept-task-force-set-the-rules/From Part 3 – On Wind-Required New Transmission Lines Finally, the building of enormous, high-voltage transmission lines that the regional electricity system operator says are required to move substantial amounts of wind power to markets south of Maine was never even discussed by the task force – an omission that Mills said will come to haunt the state.“If you try to put 2,500 or 3,000 megawatts in northern or eastern Maine – oh, my god, try to build the transmission!” said Mills. “It’s not just the towers, it’s the lines – that’s when I begin to think that the goal is a little farfetched.” https://www.pinetreewatchdog.org/flaws-in-bill-like-skating-with-dull-skates/

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Vince Lombardi 

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