Is Biomass Burning Worse than Coal? Kevin Bundy & Brian Nowicki Center for Biological Diversity

A: “It depends.” What exactly is “biomass”? Why do some people think burning biomass is “carbon neutral”? What are the policy implications? What does the science say? How is this all playing out in the real world?

What is biomass?

Major Uses of Biomass

So why do people think biomass has no effect on the climate?

The “Natural Carbon Cycle” Theory NASA Earth Observatory

Problems with “Natural Carbon Cycle” Theory Immediate emissions to atmosphere that may persist for centuries Reduced carbon stocks Reduced sequestration capacity “Carbon Debt” period: how long it takes for new growth to resequester emissions Questions: - what’s the “baseline”? - what about “anyway” emissions?

The “Inventory” Theory Derived from IPCC accounting convention Biogenic emissions accounted in land use sector, not energy sector: “Note that CO2 emissions from biomass fuels are not included in the national total but are reported as an information item. Net emissions or removals of CO2 are estimated in the [Agriculture, Forestry and Other Land Use] sector and take account of these emissions.” IPCC Guidelines for National Greenhouse Gas Inventories

IPCC Guidance Misinterpreted "The combustion of biomass and biomass-based fuels also emits greenhouse gases. Carbon dioxide emissions from these activities, however, are not included in national emissions totals because biomass fuels are of biogenic origin. It is assumed that the C released during the consumption of biomass is recycled as U.S. forests and crops regenerate, causing no net addition of CO2 to the atmosphere." -- US EPA, US GHG Inventory , page 3-1 (energy chapter).

Problems with “Inventory” Theory “If more trees are growing than we’re cutting, it has to be carbon neutral, right?” Not necessarily: - no domestic regulation of forest emissions -international demand leakage -regrowth from prior deforestation

World Resources Institute, State of the World’s Forests (2009) Global Forest Loss

Policy Repercussions US: - subsidies, tax breaks and cash grants - regulatory exemptions (e.g., EPA’s “deferral” of biomass CO2 regulation under Clean Air Act) States: - renewable portfolio standards - regulatory exemptions (AB 32)

California cap-and-trade rule § Emissions without a Compliance Obligation. Emissions from the following source categories… count toward applicable reporting thresholds but do not count toward a covered entity’s compliance obligation set forth in this regulation. These source categories include: (a) Combustion emissions from biomass-derived fuels (except biogas from digesters) from the following sources: (1) Solid waste materials; (2) Waste pallets, crates, dunnage, manufacturing and construction wood wastes, tree trimmings, mill residues, and range land maintenance residues; (3) All agricultural crops or waste; or (4) Wood and wood wastes identified to follow all of the following practices; (A) Harvested pursuant to approved timber management plan prepared in accordance with the Z’berg-Nejedly Forest Practice Act of 1973 or other locally or nationally approved plan; (B) Harvested for the purpose of forest fire fuel reduction or forest stand improvement; and (C) Do not transport or cause the transport of species known to harbor insect or disease nests outside zones of infestation or quarantine zones identified by the department of Food and Agriculture of the Department of Forestry and Fire Protection, unless approved by these agencies.

What Does the Science Say? CO2 is CO2: atmosphere can’t tell Biomass produces more CO2 per unit of energy than fossil fuels Time scale matters: - What “carbon debt” periods make sense, given that global emissions must peak by 2020 at the latest and decline sharply thereafter?

UN Environment Programme, The Emissions Gap Report (2010) Pathways to 2 Degrees C

Other Factors Feedstocks matter: - whole trees incur longer “debt” periods - harvest intensity affects “debt” - “waste”: how to define it? Fossil fuel displaced matters: - longer “debt” periods for natural gas - what’s really being displaced? → Life cycle + forest carbon analysis

So Is Biomass Worse than Coal? Manomet (2010): - Biomass: more CO2 per unit of energy - Carbon debt relative to fossil fuels takes decades to repay - Debt period varies with harvest intensity McKechnie (2011): - Burning pellets from standing trees instead of coal increases emissions for 38 years - Ethanol from standing trees does not pay back carbon debt within 100-year period

Northern Michigan “Woodsheds”

Forest Fuels Reduction Miller et al (2006)US Forest Service

“ Green grows the biomass, soft falls the dew Glad was the climate when I logged you And in the next century I hope you'll prove true To be carbon neutral and sustainable, too.” --Traditional

Questions/Discussion?