If you ever wondered how, exactly, a burning a pile of wood, AKA biomass energy, could possibly be carbon neutral (as has been long assumed) you’re not the only one.
Last week, the state of Massachusetts moved to impose new rules on the state’s biomass industry following release of a controversial study of the carbon impact of bioenergy.
Until recently, it was a common assumption that energy derived from burning biomass — organic material like wood chips or corn stalks — was carbon neutral, because the material would rot and release its CO2 anyway. The theory is that whatever greenhouse gases that are released during burning will be reabsorbed by that organic fuel source when it regrows. Of course, this assumes that the organic material will regrow.
Last month a widely-reported study by the Manomet Center for Conservation Sciences, commissioned by the Massachusetts Department of Energy Resources (DOER), upended that assumption, prompting headlines such as “electricity from wood worse than coal.”
On Wednesday, Ian A. Bowles, the Massachusetts secretary for energy and environmental affairs acted on the conclusions of that report, asking the DOER in a letter to tighten the state’s rules on the use of biomass for power generation. The new rules threaten the livelihood of the popular renewable energy industry in Massachusetts, and possibly elsewhere.
The proposed rule changes include mandating combined heat and power biomass plants because they are more energy efficient; requiring renewable energy from biomass to have half the GHG emissions of “the most efficient commercially available” natural gas plant; and requiring that biomass fuel come from sustainable sources.
In the case of bioenergy crops, like switchgrass, that fuel would have to be proven to sequester more carbon than whatever would otherwise be growing on that cropland, according to the letter.
The biomass industry reacted strongly to the proposed rules. Bob Cleaves, president and CEO of the Biomass Power Association, told Biomass Magazine that the standards outlined in the letter seem to be “made up” as they go along and he is concerned that the biomass industry in Massachusetts might not be able to meet them.
Meg Sheehan, Chair of the Stop Spewing Carbon Ballot Campaign, said “this is a groundbreaking development that means an end to commercial biomass electric power plants in Massachusetts.”
The Stop Spewing campaign sought a ballot initiative to limit biomass plants to 250 tons of carbon emissions per megawatt hour of electricity generated, but announced it would drop that initiative following the proposed rule changes.
The Manomet study released June 10 found that burning wood for energy can result in an initial “carbon debt” because burning wood releases more CO2 into the atmosphere per unit of energy than fossil fuels (oil, coal, or natural gas). While that carbon debt can be eventually reabsorbed by regrowth of the fuel stock and turned into a “carbon dividend,” the study found that in some cases it would take as long as 90 years just to pull even with CO2 emissions from fossil fuels (specifically, natural gas).