THE CLAIM “BURNING WOOD IS CO2 NEUTRAL” IS FAR FROM THE TRUTH

Vermont’s wood burning harvest was 354,462 cords, or 886,155 green ton for firewood + 347,342 green ton for electrical generation = 1,233,497 green ton in 2014. See URL.

http://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/Forest_B...

About 347,342/719,033 = 48% of total electrical tonnage was harvested in Vermont. See below table and URLs.

NOTE: A standard ton of green wood is 45% H2O, and dry wood is 50% carbon. Burning one ton of green wood creates 2000 x (1- 0.45) x 0.5 x (44/12)/2000 = 1.00833 ton of CO2 emissions.

NOTE: Below are listed the wood tonnage and combustion CO2 tonnage of Vermont’s wood chip power plants in 2015.

* On an A to Z basis, there is about 25% more CO2 not related to combustion, such as logging, chipping, transport, ash disposal, waste disposal, O&M of the plant, etc.

http://www.maforests.org/McNeil Emissions 2015.pdf

http://www.maforests.org/RYEGATE TECHNICAL.pdf

http://fpr.vermont.gov/sites/fpr/files/About_the_Department/Library... 

http://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/Forest_B...

http://www.maforests.org/VermontBiomassBiomess.pdf

CO2/MWh of Power Plants: The Vermont McNeal and Ryegate wood-chip power plants have CO2 emissions/MWh 4 times greater than a gas-fired combined-cycle gas turbine, CCGT, plant. Example: 3412000 Btu/MWh/0.55 x 117/1000000 = 727 lb CO2/MWh. The other pollutants of wood per MWh are about 4/2.4 = 1.67 greater than of coal.

https://www.eia.gov/tools/faqs/faq.php?id=73&t=11

Plus about 15%, if wood chips, plus about 30%, if wood pellets

Combustion CO2 Only: Logging proponents claim “burning wood is CO2 neutral”, because the regrowth of the forest reabsorbs the CO2.  They do not mention the other 25% of CO2 not related to combustion. See below.

The CO2 of a wood power plant gets released over a year, but, in New England, the CO2 is reabsorbed by regrowth over a period of about 40 years. In Georgia, with fast-growing Georgia pines in planted, fertilized forests, the CO2 is reabsorbed over a period of about 20 to 25 years.

The accumulation and reabsorption of the CO2 of the Vermont McNeil and Ryegate wood-chip fired power plants over a period of 40 years is shown in below table. Only the first 5 years are shown. The maximum CO2 occurs in year 5. If 6 years were shown, the maximum CO2 would occur in year 6, etc. The absorption rate is assumed at a constant 18126 ton/y to simplify calculations.

The cumulative CO2 continues to increase each year until year 40. See bold value in table. The CO2 of year 40 would be entirely reabsorbed in year 80. The wood burning proponents claiming “burning wood is CO2 neutral” is purposefully deceptive to fool lay people. It is far from the truth. 

The above is for just two wood-burning power plants. But throughout the world there are thousands of wood-burning power plants, plus wood-burning heating plants. Their combustion CO2 is sequestered in the same manner, provided there is enough remaining healthy forest area.

Thus, a permanent fraction of the CO2 due to wood burning in the atmosphere is due to:

1) Wood burning by power and heating plants

2) Wood burning for building heating, cooking, etc

3) On-going, worldwide forest fires

The 25% of Additional CO2 Not Related to Wood Burning: That CO2 is due to the following:

- Harvesting, chipping, pelletizing, transport of wood to plants and buildings.

- Energy embedded in machinery and its replacement and operation.

- Energy embedded in power and heating plants and building heating systems and their replacement and operation.

- Energy embedded in the production facilities of the machinery and parts making for the plants and heating systems.

Quantifying the CO2 of each category is a time-consuming activity, but is required to determine the lifecycle, cradle to grave, CO2 emissions, so one pathway can be properly compared with another.

APPENDIX 1

Here are some URLs regarding wood burning.

http://www.windtaskforce.org/profiles/blogs/is-burning-wood-co-2-ne...

http://www.windtaskforce.org/profiles/blogs/wood-for-fuel-logging-i...

http://www.windtaskforce.org/profiles/blogs/a-comparison-of-wood-ch...

http://www.windtaskforce.org/profiles/blogs/more-realistic-energy-s...

http://www.windtaskforce.org/profiles/blogs/dismal-economics-and-in...

http://www.windtaskforce.org/profiles/blogs/is-wood-burning-carbon-...