Study points out inherent flaws in Manomet woody biomass study

By Lisa Gibson | May 19, 2011

A new study contradicting the findings of the well-known 2010 Massachusetts biomass study by the Manomet Center for Conservation Sciences points out inherent flaws and incorrect assumptions in the Manomet authors’ methodology. In short, the inaccuracies lead to flawed findings, which have prompted sweeping policy changes in Massachusetts that threaten to wipe the use of woody biomass off the map in the state.

The Manomet study found and outlined a debt-then-dividend model for using woody biomass to generate electricity, saying it can take decades to pay back the carbon debt. In the new study, however, William Strauss, president of FutureMetrics, says Manomet has it backwards. “The Manomet study implicitly assumes there’s a carbon debt before dividend,” he said of his report, ‘How Manomet got it Backwards.' “The presumption is you’re increasing carbon. My thesis is the dividend has already been accrued.” The Manomet authors are so deeply ingrained into their logic, he adds, that they allow no conclusions other than those that accrue from their debt-then-dividend model, thus limiting the scope of their view of the world and removing information from the system.

Strauss says that there is in fact no debt for several reasons, one being the flawed assumption Manomet uses to suggest that a stand of trees is chosen and then every single tree is harvested from it. “In actual forest systems, assuming sustainable forestry practices, the carbon released by combustion from selective harvesting is offset by carbon accumulation from the rest of the system’s continued growth,” Strauss writes.

For example, if there is a forest system with 1 million tons of biomass on Jan. 1 of a given year and that system has 1.01 million tons on Dec. 31 of that same year, the forest has increased its carbon stock over that given year and it is embodied in the extra 10,000 tons of biomass. If 10,000 tons are harvested on Dec. 31, the system begins the next year with the stock of biomass and carbon at the same level it had at the beginning of the previous year. “What you release into the atmosphere is only what you’ve accrued that year,” Strauss explains. “[Manomet authors are] under the assumption that you go cut down a tree and stand there and wait 30 to 50 years while it regrows.” The Manomet authors lean on the assumption that carbon accounting begins when the tree is harvested.

Strauss continues in his report supposing Manomet’s axiomatic assumption and carbon accounting begins at a point in the past. “In our 1 million ton system, if we start our accounting on Jan. 1, we accrue our dividend first before we harvest the benefits,” he writes. “There is never a debt. Let’s call this a ‘dividend-then-benefit’ logic.” The underlying conclusion, he says is clear: if biomass is harvested from existing forests that will be sustainably managed in the future, there is no debt.

The Manomet study is only an analysis of Massachusetts woody biomass use, but that fact is sometimes lost in the chatter surrounding it. Strauss says he is by no means a Massachusetts expert, so instead uses figures and statistics from Maine forests in his study to prove his points.

“Wood-to-energy from sustainably managed forests, as this paper has shown and as all of Europe has codified in its carbon accounting rules, can provide net zero carbon emission or even positive carbon sequestration if the woody biomass stock is not depleted or grows over time,” he concludes.

Strauss released his study May 18 to about 200 recipients, he said, including some Manomet authors. “I do expect a response,” he said. “I suspect there will be some back and forth.”

Strauss said he does not have a goal of upsetting the course of policy changes in Massachusetts that are based on the Manomet study. Earlier in May, the Massachusetts Department of Energy Resources (DOER) released its final regulations pertaining to woody biomass qualification for the state’s renewable portfolio standard of 20 percent by 2025. The final regulation is no more friendly toward biomass power than the previous proposal and is expected to be implemented swiftly as ordered by the Massachusetts Executive Office of Energy and Environmental Affairs.



14 Responses

  1. Woods



    I thank you humbly for shranig your wisdom JJWY

  2. T. Silva


    2 for a different view of the biomass haters in Mass.

  3. Juergen J. Denker



    Sorry for coming late into the discussion. Someone should have pointed out to Mrs Booth that you have never a closed system. In her special case she omitted the intake of energy, namely sunlight. Furthermore, she conveniently assumed that 'someone comes in and burns half of those trees'. But that is exactly what Dr Strauss advises NOT to do. Instead he points out, you only extract the surplus of biomass developed over a certain time.

  4. Joseph Zorzin



    Regarding what Les Blevins says above, "Burning wood to replace oil strikes me as counterproductive and ludicrous. But not burning it, and yet still delivering BTUs and Char may make sense." As a working forester- it would be just fine if his non buring alternative were to become available.One of my clients is an executive for a company, Core, which produces energy and biochar from wood with zero carbon emissions: They're building biomass systems around the world including on U.S. aircraft carriers (not using wood of course). I'm sure many other firms can do this, but why are they not active in New England, or are they? Why didn't Manomet review this alternative? Who could object to such a system? Is it too good to be true? Joe

  5. Joe Zorzin



    Correction: I had quoted Mike Bertin, not Les Blevins.

  6. Jesse Sewell



    The Manomet Study is a joke. Anyone who understands forest Economies and how Timber is managed cannot begin to justify the assumptions made in that study. It is nice to see someone put forward a thoughtful, scientific rebuttal.

  7. William Strauss



    I thank Bob Perschel for his comments. His point of view is very respectful and his perspective on policy making is useful. The discussion over what policy makers should know and understand is important. I certainly do not want to confuse anyone. But the foundation for the discussion has to be built upon a factual understanding of the reality of what wood-to-energy means. There are folks at every point on the continuum in this mix. At one end of the spectrum are advocates for never cutting a tree for any reason and regaining a land of old growth forests. At the other end are folks that would ignore the ecological and environmental disaster that would accrue from cutting and taking all of the trees for short term gain. I hope that a reasoned discussion can lead to a reasoned understanding of how to best manage the use this renewable and sustainable energy resource. One thing is certain; there is a secular shift in world demand for paper for printed media. If you talk to people in the printed media business, there is great uncertainty. The data backs that up. Paper demand for newspapers, magazines, catalogues, books is declining at an increasing rate. If the forest products industry is to adapt to the inevitable decline in demand for pulpwood, it will have to find other markets. There is an opportunity here to save this valuable industry and help contribute to our energy independence and mitigate GHG emissions from fossil fuels. Working forests that provide an annuity to their owners remain forests. Idle forests, particularly in urbanized states like MA, get cleared for urban development and disappear forever. That is another fact that seems to be missing from the study. I am troubled by one sentence in the comment that Bob makes: "Therefore, the Manomet study looked at what would happen if funding was used to increase the harvest of biomass...” If one starts with the premise that wood-to-energy requires an increase in the harvest then of course the balance of growth to harvest changes and there will be net increase in carbon emissions (but only by the incremental increase over the long term equilibrium growth rate NOT by the entire harvest). The central thesis of my paper, supported by the entire last section of the paper showing data for Maine, is that many large working forest systems have been in growth to harvest equilibrium for a long time. Given that equilibrium (or growth to harvest greater than one as Maine exhibits) there is no carbon debt. The whole idea of my paper is that if harvest is about the same every year in the past and in the future, there is no debt. All this concern about increased carbon emissions is in error if those conditions are met. The premise that harvest has to increase due to some “funding” may be correct for MA which, as the paper points out, has a much more limited forest products industry. But wise policy should not approve any funding that would allow unsustainable practices. Some might say that this is a slippery slope. Once we go down the wood-to-energy path, we will cut down all of the woods. One can look to Austria to see a model of a country with a strong policy for wood-to-energy that has been in place for decades where the forests are not only not shrinking but are getting healthier because of regular thinning due to the demand for so-called low grade wood for energy (see my article in Pellet Mill Magazine). The policy battle here should not be whether or not wood-to-energy is a good idea, but should be how to make sure that our working forest resources are managed for health and maximum sustainable energy yield while preserving an ecological foundation for habitat and human visitors. There is a lot of good work in the Manomet study specific to MA. But continuously lurking in the shadows is the assumption that every bit of wood that is harvested and converted to energy is depleting the net stock of wood in the forest system (at least until those trees regrow over decades). That assumption flies in the face of facts. In Maine at least the net stock of wood is getting larger every year in spite of 16 million tons per year every year for the last 3 years being harvested from across almost 18 million acres of forested land. So my paper I think is not only right but is an important bit of information to help our policy makers make good policy.

  8. William Strauss



    Correction to a typo: The next to the last sentence should say "per year every year for the last 30 years..." not 3!!

  9. Joe Zorzin



    I've read just about everything written on the biomass debate in Mass. including the Manomet Report, several reports critical of it, this article by Dr. Strauss, Bob Perschel's comments on this site and Dr. Strauss' reply. It's my opinion that the final word has yet to be written. There are assumptions in all positions taken on this subject, pro and con. The subject is extremely complex. Anyone who presumes to have all the truth is foolish. Meanwhile, I don't see the rest of the world anxiously trying to stop all carbon emissions- I don't see the anti biomass people refusing to fly in carbon spewing jets, or going vegetarian, or calling for zoning controls to prevent urban sprawl, or demanding that we shut down the interstate highway system so we can build a mass transporation system as China is now doing. There are extremists on both sides of this debate and those extremists refuse to see any truth in the other side- which should be a signal that this debate is far from over. The state of Mass. should be careful with this. No doubt stopping biomass electric is the way to go, but I don't see them making any effort to promote smaller CHP facilities like those proposed in Pownal or Fair Haven, VT which are very efficient and produce pellets for ordinary citizens who can no longer afford home heating fuel. That would be a good compromise solution, but I think the state has decided to go with the anti biomass Jihadists instead, the only place on the planet to do so. They've made their choice, but they may look foolish as the science improves.

  10. Genevieve C Fraser



    If I were to characterize the difference between the Mary Booth/Chris Matera view of forest harvesting/biomass vs. the William Strauss vision, the anti-crowd has a mechanistic or mechanical view versus Strauss' more organic assessment. To quote ee cummings in his poem, pity this busy monster, manunkind, "....A world of made is not a world of born..." It would be absurd to assume that when a person of say 80 years of age dies, one must wait for another to be born and live to 80 years before that life force has somehow been renewed. People are born, live and die on a continuous basis. So too are forests. What is being debated is a woodlot (counting each tree) point of view vs. the landscape vision...the mosaic of various stages of growth...the continuum of life approach. Also, in most cases, only a portion of the wood that is cut would be turned into biomass, burned and emit carbon. A large percentage would be maintained as stored carbon through lumber and other wood products. Therefore, the carbon storage is increased through both regeneration and the creation of wood products and a smaller percentage is emitted back into the atmosphere. Genevieve

  11. Laurenz Schmidt



    From a technical and logical perspective Bill Strauss has it right, he starts from a (natural) status quo, not from an absolute Zero. If his findings do not support a politically expedient outcome, too bad. It is always bad science to “study” a system with an intended outcome in mind. I want to respond to Mary Fraser’s comment. She may want to think the picture through first before offering an opinion based on a partial view of the facts. She says "imagine what would happen if someone would burn half the trees.”… Well, I want to turn it around and ask what would happen if NO ONE would burn these trees. The trees would grow old and large, allowing fewer young trees with higher sequestration rates of carbon per year and acre to come up. So the area specific sequestration and incremental annual storage capacity of the "closed system forest" would go down over the years! Provided there would not be a natural forest fire, burning ALL of the trees, THE TREES WOULD DIE OF OLD AGE! What would happen next, their wood would undergo decay, part of which is a composting process. A substantial portion of the carbon they stored over their lifetime will be released in form of methane (CH4), the rest in form of CO2. CH4 is a far more potent greenhouse gas than CO2(25X). Eventually the CH4 would get oxidized to CO2 too (photochemical reaction with O2), but not before it captured and retained quite a bit of sun energy in form of heat in the atmosphere. Burning the trees, on the other hand, releases all the carbon they stored over time in form of CO2 for recycling in the photosynthesis process. It seems using a biological arboreal cycle to make use of the sun energy that falls on the earth anyway is a smart thing to do. Yes, with care and foresight, mindful of sustainability and reduction of waste, re-forestration, erosion control, short transportation losses, etc. – nevertheless smart.

  12. Laurenz Schmidt



    Correction: Sorry, I meant to reply to Mary S. Booth's comment. Not to "Mary Fraser", as I erroneouly wrote. My apologies.

  13. Mike Bertin



    I look at this problem slightly differently than either Mr Strauss (whose viewpoint seems to support continued forest commercialization) vs the purists (who tend to wish no one cut down anymore trees). - no slight of any kind intended to either group. I start with a more basic it more carbon neutral to burn fossil fuels to generate power, supply plastc water bottles, and run vehicles, planes and ships - OR is it more carbon neutral to utilize biomass (some of which could be considered virgin products (forestry) and some of which might be considered waste products {MSW for instance}) for the same energy generation. Notice I said utilize, not burn. MR. Strauss' assumption on diminishing paper products usage is well founded. And with the constriction of the housing market, do we now have a renewable crop (wood) that should be viewed much as corn is? Ethanol production utilizing feed crops results in diminished use of fossil cruide but is it carbon neutral? And it has the accompanying impact on food supplies. I am also referring to the recent breakthroughs in pyrolyization resulting in low oxygen, high hydrogen bio-crude ( as a direct fossil crude replacement)and its ash equivalent of carbon sequestering Char. I think this last byproduct introduces another positive variable into the discussion that has not been accounted for in previous studies. Burning wood to replace oil strikes me as counterproductive and ludicrous. But not burning it, and yet still delivering BTUs and Char may make sense. However, I, like most of you agree that further analysis and discussion is beneficial.

  14. Les Blevins



    Think about it.. All forms of energy demand are on the rise and yet "Peak Oil" has now passed, Coal Generation is under increasing pressure, and Global Warming is producing enormous amounts of biomass in the forms of vast numbers of insect killed trees, vast amounts of storm and flood debris, vast areas of flood or drought killed food crops such as wheat, beans or corn that is now only good for the biomass standing grain-less and worthless out in the fields and in the way of replanting more crops, not to mention millions of tons of municipal wastes available as scrap tires, municipal trash or sewage that society must pay to dispose of. The AAEC SG fuels conversion system will prove to be the world's best when it comes to being capable of using diverse feedstocks and using multiple conversion processes in the production of renewable heat, electric or mechanical power, chemicals, biofuels and biochar. Wood fuel in pellet form is the subject of the first attachment. But the AAEC system can automatically utilize loose fuels as well as fuels in the form of pellets, cubes, briquettes, blocks and bales of all sizes and shapes. I believe it will prove to be the Swiss Army Knife of fuels processing systems once the world gets to see it in action. Project integrators that pick which technologies to use on the front end and the back end will appreciate the fact that installing the AAEC system as the "front end technology" will not lock their project into only one type of fuel feedstock or even one process for fuel conversion. See figure #1 in the attached pdf and the other attachments that indicate a steady supply of wood in the USA (beetle killed pines) and agricultural waste such as drought or flood killed crops and hundreds of thousands of homes and businesses and millions of trees left destroyed in the wake of floods and storms as debris that must be cleaned up by society and disposed of, often with tipping fees. All we need to do is find a few $million dollars in funding to validate a multi $billion dollar fuels conversion technology and we will be off and running. Les Blevins


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