“Although we strongly support policy efforts to reduce greenhouse gas emissions and health-damaging air pollution from fossil fuels, we are concerned that the PTC includes support for biomass combustion technologies that both contribute to climate disruption and threaten public health.”
– Letter of December 11, 2012, to Senate and House Leaders from 40 environmental-related organizations (reprinted below)
Biomass energy has been called the air emission renewable. Technical studies have concluded that energy made from plants and woody matter can require so much (fossil) energy and stir up release of carbon dioxide as to negate CO2 reduction.
This problem has been long recognized in the environmental community. “Although biomass is a renewable resource, much of it is currently used in ways that are neither renewable nor sustainable,” stated Chris Flavin and Nicholas Lenssen in 1994. 
In 2001, the International Energy Agency (Organization for Economic Cooperation and Development, 2001), concluded:
Biomass energy is generally considered to be CO2-neutral, as long as it is consumed in a sustainable manner, i.e., the stock of biomass does not diminish. This is not the case in many developing countries, where over-consumption of biomass fuels leads to deforestation and hence to the reduction of forest-based CO2 sinks. 
And the debate/controversy continues. Last week, a letter to the House and Senate leadership from 40 left-of-center environmental-related nonprofits, groups, and businesses urged that biomass be excluded should the renewable-energy Production Tax Credit be extended past its year-end expiration date.
Addressed to Majority Leader Reid, Minority Leader McConnell, Speaker Boehner, and Minority Leader Pelosi, the December 11, 2012, letter read:
We, the undersigned organizations and individuals, understand that many of our colleagues in the environmental community have urged you to extend the Production Tax Credit (“PTC”) in Section 45 of the Internal Revenue Code for wind and other renewable generation technologies.
Although we strongly support policy efforts to reduce greenhouse gas emissions and health-damaging air pollution from fossil fuels, we are concerned that the PTC includes support for biomass combustion technologies that both contribute to climate disruption and threaten public health.
Recent published, peer-reviewed science has shown that combustion of biomass, especially woody biomass sourced from forests, can increase carbon dioxide emissions relative to fossil fuels over a time span of decades to centuries. A large-scale shift to biomass generation could cause carbon pollution to increase at precisely the time scientists are telling us we need to make rapid and steep emissions reductions.
Moreover, unlike other renewable generation technologies, biomass combustion produces air pollutants (including particulate matter and nitrogen oxides) that have well-known and adverse effects on public health.
Accordingly, we respectfully urge you to not extend the PTC for biomass generation as proposed in legislation passed by the Senate Finance Committee. In a time where we have extremely limited public resources available, we must support renewable generation technologies that reliably reduce greenhouse gas emissions without contributing to adverse public health effects.
We would be happy to provide information or discuss this further at your request. Thank you for your consideration.
Arise for Social Justice
Biomass Accountability Project
Blue Ridge Environmental Defense League
Buckeye Forest Council
Center for Biological Diversity
Center for Community, Democracy and Ecology (CCDE)
Citizens Alliance for a Clean Health Economy
Citizens for a Safe Environment
Concerned Citizens of Russell
East Jefferson Biomass Committee, North Olympic Group, Sierra Club WA
Energy Justice Network
Friends of Bell Smith Springs
Friends of Robinson State Park
Global Alliance for Incinerator Alternatives
Green Party Oklahoma
Healthy Dubois County
Lin Schutz homeowner MPLS, MN
Market Air Quality Campaign
Massachusetts Forest Watch
Partnership for Policy Integrity
Port Townsend, WA Citizen Watchdogs
Protect All Children’s Environment
Protect the Peninsula’s Future
SAMPLER (Southern Appalachian Media Project for Literacy on Environmental Renewal)
Save America’s Forests
Save Our Rural Oregon
Save Our Sky Blue Waters
Schmid & Company, Inc.
Selkirk, Coeymans, Ravena against Pollution (SCRAP)
Stop Toxic Incineration in Springfield
The Enviro Show on WXOJ
Tom Neilson Music
Work on Waste, USA
 Chris Flavin and Nicholas Lenssen, Power Surge (W. W. Norton, 1994), pp. 176-77.
 International Energy Agency, Toward a Sustainable Energy Future (Paris: Organization for Economic Cooperation and Development, 2001), p. 204.