The Impact of Wind Farm Deforestation on Air Quality and CO2 removal
April 30th, 2013
The premise upon which the ‘fast track’ permitting and subsidizing Wind farms was based was the role they played in replacing electricity generated from CO2 emitting power plants with renewable energy from ‘clean’ wind.
The overwhelming, nearly universal recommendation coming from the Copenhagen Climate summit was that the solution to CO2 based global warming was reforestation, and many nations like China have planted millions of trees in response.
Two years ago I organized a planting of over 500 trees in Mid Coast Maine on newly acquired land trust tracts with the cooperation of the Rotary Club, local high school community service programs, and a forester from the Conservation Land Fund.
Prior to the perfection of the iTREE computer software by the U.S. Forest Service, it was arduous and time consuming to measure the impact of each individual tree in a forest on converting CO2 into oxygen and stored carbon; and in removing other pollutants.
However with the recent release of CANOPY and ECO models that work in conjunction with GOOGLE’s aerial maps, it is possible to assess the impact of cleared wind farm sites. A number of cities have invested in the software and assisted by regional forest research centers; produced accurate assessments of the ability of a forest to cleanse the air of pollutants, including CO2, and store carbon up to 100 years.
This is a sample taken from one such analysis, the ADRIAN Urban Forest Effects and Values, October 2012:
“Pollution removal by trees and shrubs in Adrian was estimated using field data and recent available pollution and weather data. Pollution removal was greatest for ozone. It is estimated that trees and shrubs remove 40 metric tons of air pollution (ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), particulate matter less than 10 microns (PM10), particulate matter less than 2.5 microns (PM2.5), and sulfur dioxide (SO2)) per year with an associated value of $430 thousand based on estimated local incidence of adverse health effects of the BenMAP model and national median externality costs associated with pollutants” .
“Climate change is an issue of global concern. Urban trees can help mitigate climate change by sequestering atmospheric carbon (from carbon dioxide) in tissue and by altering energy use in buildings, and consequently altering carbon dioxide emissions from fossil-fuel based power plants” .
“Trees reduce the amount of carbon in the atmosphere by sequestering carbon in new growth every year. The amount of carbon annually sequestered is increased with the size and health of the trees. The gross sequestration of Adrian trees is about 1,450 metric tons of carbon per year with an associated value of $114 thousand. Net carbon sequestration in the urban forest is about 528 metric tons. Carbon storage and carbon sequestration values are calculated based on $78 per metric ton.”
Now run the analysis in reverse and you see how deforestation for access roads, transmission lines and turbine ‘foot prints’ radically reduces the ability of the forest to remove CO2 and other pollutants, and to add in life-giving oxygen!
Yet, based on the permitting of wind farms in Maine this loss of Carbon absorption and restoration of oxygen is not factored in any calculation of subsidies, and the PRODUCTION TAX CREDIT is not adjusted to reflect this loss of Carbon removal!
The proposed Bowers Mountain wind farm site in Eastern Maine will overlook a lakes region and features:
16 Turbines, each 300’ tall, potentially with a ‘foot print’ of a circle roughly 600’ in diameter; or about 0.70 acre.
The U.S. Environmental Protection Agency (EPA) estimates that planting one acre of trees on marginal land would sequester 0.6 to 1.6 metric tons of carbon annually in the first five years of growth.
The actual amount of carbon sequestered by a forest depends on a large number of factors, including the region of the country, the type and mixture of trees in the forest, the age of the trees, the site class (relating to the height of the dominant trees at 50 years of age), and the reference land use as a baseline (e.g., clear cut forest, cropland, or pasture).
Assuming that planting one acre of trees in the Southeast will sequester about 1.0 ton of carbon each year (slightly less than the median of the EPA estimated range), and that 1.0 ton of carbon is contained in 3.67 tons of CO2, then one acre of trees planted on marginal land will sequester (save, reduce, or prevent from escape to the atmosphere) about 3.67 tons of carbon dioxide each year during the first five years.
Given the wide variety of factors to consider it is speculative to indicate how much carbon is lost by clearing those 33 acres, but approx. 120 tons of carbon dioxide will no longer be sequestered every year.
This demands a thorough study of the site be done using iTREE software to determine the impact on air quality and in turn to reduce the amount of subsidy received based on carbon no longer sequestered.
Removing forest for a wind farm, access roads, and transmission lines reduces the ability of that wind farm to continue to improve air quality by photosynthesis
Wind farms reap carbon subsidies while not paying a price for the lost ability of cleared forest land to improve air quality
Production Tax Credits should be fairly adjusted to reflect this loss in carbon sequestration and ability to remove air pollutants.
frank j. heller, MPA
public policy analyst.