On an atomic level, one molecule of CO2 is identical to the next, regardless of its source. Each molecule is composed of two oxygen atoms covalently bonded to a single carbon atom. Each molecule is a greenhouse gas (GHG) which transmits visible light and adds to global warming. So should it really matter whether a particular molecule of CO2 is the byproduct of the combustion of woody biomass or coal and other fossil fuels?
The EPA’s Call for Information relating to this topic closed mid-September. It is unclear whether the EPA will change its earlier decision not to exempt biomass from its recently adopted “Tailoring Rules” which prescribe Clean Air Act permitting requirements for GHG emission sources beginning January 2, 2010. As written, the “Tailoring Rules” treat emissions from burning biomass the same as emissions from burning coal or other fossil fuels. Congress is expected to vote on proposals to block or delay these rules and litigation opposing the rules is currently underway. But some states may very well find themselves scrambling to revise their State Implementation Plans (“SIPs”). In September, the EPA released a proposed determination that 13 states’ SIPs are “substantially inadequate” and a second rule that allows the EPA to assume responsibility for the permitting of GHG emissions for those states that do not timely submit compliant SIPs.
But, returning to the initial question: Is all CO2 created equal? If woody biomass is actually “carbon neutral” then perhaps biomass-produced CO2 emissions are better than those from coal and other fossil fuels. All wood will decay and release carbon into the atmosphere at some point; the same is not true for coal and fossil fuels. Thomas McLain sums up the argument for different standards nicely in a recent opinion column he did for OregonLive.com. “The carbon dioxide released from the combustion or decay of woody biomass is part of the global cycle of biogenic carbon and does not increase the amount of carbon in circulation. In contrast, carbon dioxide released from fossil fuels increases the amount of carbon in the cycle.” He goes on to say that “[t]he carbon released from burning fossil fuels has been long considered by scientists as separate from the global carbon cycle and adds to the total amount of carbon in active circulation between the atmosphere and biosphere.”
A lot has been said about carbon neutrality. It is imperative that we develop accepted, reliable, and standardized measurement and accounting tools to test the neutrality of energy production. But carbon neutrality shouldn’t be the gold standard. Even if biomass isn’t entirely carbon neutral, biomass emissions are preferable because they are the byproduct of a renewable and otherwise wasted energy source.
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