Wood pellets and biomass as energy sources

Can anyone point me to studies, or any rational argument, for how supplanting fossil fuels with biomass or manufactured wood pellets can be better for climate?

Thanks!

Hi Bruce, I’m sure they’re out there, but I’ve only been exposed to the arguments against it, e.g. https://www.dogwoodalliance.org/2020/10/industrial-logging-and-the-wood-pellet-industry-hurt-us-all/

I’ll email you an additional item.

Best - Jason

As with Bruce, I’m sure they are out there. My experience is with the LCA for structural building materials, referred to as mass timber. In that regard, the saving grace is largely due to fact that wood is a carbon sink, obviously not the case if it’s being burned. However, if the pellet’s are manufactured from the manufacturing waste of the mass timber process that would be a plus.
The other VERY LARGE caveat is the question of where the wood comes from and how the forest is managed. It is imperative to have a third party certification on the forest and the forestry practices. transportation distance is also of course a major consideration.
I’m skeptical of the idea of biomass for energy and will look forward to further replies.

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Thanks, Patrick. I have uncovered plenty of credible sources saying what we expected: the wood pellet idea is NOT good for climate, e.g., https://www.audubon.org/news/lets-say-it-again-wood-pellets-are-not-sustainable-fuel-source

That’s a great topic, and I find the analogy with timber products troubling.

My understanding is the same as @pdoss-smith (and in part thanks to @jasonegrant’s Wood Forest and Embodied Carbon Webinar). I share the same skepticism, but the dogwood alliance and the Audubon articles didn’t really help me go from skepticism to grounded belief.

The Chatham report referenced by the Audubon article seemed clearer, and it seems to say in short that:

  1. most biomass practices ignore the full carbon impact, which ends up resulting in net emissions
  2. it is hard to regulate them because it is hard to properly assess the full carbon impact
  3. therefore the safest is to only allow burning biomass from waste (as Patrick mentioned)

Now, I am wondering what makes timber and mass timber different from Biomass burning, as timber eventually burns or decays and releases back the carbon stored (Item#3 might become using salvaged wood, or also byproducts). My understanding so far was: one can consider timber products as being carbon sinks or carbon neutral if they come from sustainably managed forests such as FSC-certified ones. Is that correct?

But, just as we can wonder how much of the biomass production is actually carbon neutral, how much of the wood production is FSC-certified or equivalent? Will/Can it ever happen that all timber will come from sustainably managed forests? And if it doesn’t, the question might become: how much better are timber products compared to other building materials?

Any help clarifying this hot topic is more than welcome.

I recently gave a presentation summarizing how biogenic carbon of wood products are accounted for in Whole Building Life Cycle Assessments (WB-LCA). In that presentation, I discussed a dynamic approach to modelling biogenic carbon called “GWPbio”, which can account for factors such as forest rotation period and product carbon storage period. This is one way of quantifying the difference in climate benefit between incinerating wood (storage period = 0 years) and storing it in a building (storage period = building lifespan, which we might assume to be 60 years in WB-LCA).

Here are my slides from that presentation:

WWF and Quantis recently released a great Excel tool for quantifying these GWPbio factors. In my presentation, I showed a few preliminary scenarios that I modelled, including using wood in buildings and for bioenergy.

Hope this helps!

Cheers,
Anthony

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The Biomass Thermal Energy Council, biomassthermal.org, has information on biomass as fuel for co-gen power plants.
As with any co-gen plant, a major key to its sustainability is the capture of the waste heat as it powers turbines to produce electricity.

Bruce,

Here’s a release from the Northern Forests Center making an argument for wood pellets. I haven’t had a chance yet to dig into the study to figure out how they are valuing emissions, so I’m not in a position to defend the research, but wanted to pass it along. I will say, here in New England, we don’t have a much of a timber industry any more (Maine being an exception), especially relative to historical scales or the US southeastern/northwestern forested regions, and accordingly much of our forest products are of lower scale/quality, which makes them more favorable to applications like pellet or pulp wood rather than CLTs (I’m generalizing big time here, of course). An argument for regional, scale-appropriate pellet fuel from well-managed supply chains is that providing some market base for our regional forests helps to avoid land use changes as development pressure and management fragmentation from private ownership are among the greatest threats to thriving forest ecosystems in our region. While I’d have a hard time saying burning anything for fuel is good for the atmosphere, looking at the use of pellet fuel in the context of what it is displacing (in our region, that’s largely #2 fuel oil as natural gas pipelines don’t reach the rural areas and it’s cheaper than propane) and the regional ecosystem and supply chain in which it is being produced does support its use as a tool in the kit from my perspective. By this I’m not talking about clearcutting swaths of forests for electric generation, or shipping southern yellow pine to Europe to be burned to meet their “net zero energy” goals, mind you…

All my best,
Jacob

Well said, Jacob.
Forest management is a huge part of successful wood biomass.
The Wild Center in NYS is a great example of a scaled biomass harvest for their use at the Center.
The major problem with wood biomass at present is, as you have pointed out, the export of natural resources overseas.
There are also opportunities to grow annual crops of grasses and process that biomass into bricks or pellets for cogen facilities.
Best,

Stephen

Thanks, Jacob! Point taken, and illustrates that though harvesting and moving wood biomass around globally is probably a big loser for climate, it may still make sense in local contexts such as New England. I would guess also true in any forested rural context. Exceptions to every rule.

Great discussion. I also point to the Wood Carbon Seminars especially the section 2.1 from Reid Miner. https://carbonleadershipforum.org/wood-carbon-seminars/ Also of note, the total system is taken into account at the national scale tracking these inputs/outputs over time to get to ‘carbon neutrality’ system.

As I understand it, the key is that you’re not changing the amount of wood taken out of the forest over time but rather doing the best to use what wood is removed in it’s highest best use.

Second Kate and Jacob’s comments about efficient use of resources being the key. regional conditions and the ebb’n flow of industry makes wood byproduct tricky and emphasizes the regional temporal issues that are difficult to model or baseline.

The Alliance for Green Heat has good resources defending biomass heating and have been very active in the policy initiatives. They work with heater efficiency which is of course a mandatory piece of the puzzle and where a lot of policy has been directed.

As fuel size increases (pellet>stick>cord) the reliability of burn efficiency decreases, emphasis on reliability, as some cord wood heaters have tested at pellet efficiency in EPA labs. This matters because for rural households with existing homes. The availability of stick and cord wood is readily available and the reliability of it’s good sourcing goes up. Possibly a high efficiency cord or stick wood heater in rural areas can offset the lack of dependable pellet sourcing in the near term until the industry is more carbon regulated.

With new built homes high insulation is preferred which makes fiber combustion for heat difficult to balance heater efficiency and heat demand, as hot fast burns are the most efficient but the insulated house wants stable low heat inputs to prevent over heating. Hydronic buffer tanks with low temp hydronic distribution can help that balance as can mass heaters but there is a cost and carbon challenge that those beefed up heaters present. The low temp distribution with a buffer tank approach provides flexibility where multiple heat sources can be alternated to maximize other renewable sources or swapped in the future without disturbing the distribution system. Thus a cord wood heater could be used now in combo with a solar tied air-to-water heat pump (new to the US market), and swapped for pellet when the pellet sourcing becomes carbon credible.