Biomass Energy & Carbon Accounting (Part 3)

Sustainability

As we've discussed in prior blog posts, the EPA in its proposed "Tailoring Rules" does not consider a mass balance (inputs and outputs) approach to greenhouse gases -- only focusing on air emissions and not the source of the fuel feedstock (biomass versus fossil fuels).

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.

The below data of stoker and fluid bed biomass energy technology systems comes from Babcock Power Report, while gasification technology data for carbon capture comes from previously discussed NREL (50%)and our own estimate (30%).


While we join others in the Biomass Energy Industry to disagree with the EPA proposed position -- if these rules are implemented, is there a fall-back argument to "carbon cycle neutrality" for biomass power (electricity, combined heat and power)?

The answer is yes, through the combination of (1) gasification technology; (2) biochar; and (3) below ground carbon sequestration of growing dedicated energy crops:

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Biomass Energy & Carbon Accounting (Part 2)

Sustainability

In our last post on "Biomass Energy & Carbon Accounting" we cited an engineering science reference from the U.S. Department of Energy's National Energy Technology Lab (NETL) that ~50% of carbon emissions can be captured through oxygen starved biomass gasification technology.

In our extensive experience with biomass gasification, we feel uncomfortable with the NETL estimate -- concerned that the carbon capture percentage may be too high. Our "educated guess" is the percentage would be closer to a +30% carbon capture for commercially available biomass gasifiers (i.e., up-draft gasifier) -- which is reflected in below amended chart.



While we could be wrong (overly conservative) so could NETL.

The problem in getting a handle on the issue of carbon capture is the lack of commercially operating biomass gasifiers (providing much needed engineering data). On the topic of carbon capture (biochar), the majority of engineering science work has been either at lab scale or with small gasifiers (i.e., stoves). It should be remembered that while biochar has always been a waste product of biomass gasification, only recently has it become a critical issue. Critical in the sense of the very viability of biomass power, recognizing current questions on carbon neutrality (i.e., the EPA's Tailoring Rule").

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