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Last week in Part I of this series, I discussed the science of wood pellets and the drivers behind the dramatic increase in their production in the southeast United States. The majority of these wood pellets are being shipped to Europe, particularly, the United Kingdom where they are supplanting coal as a fuel source for electricity production. (This situation strikes me as particularly ironic, but in order to not throw of the thread of our discussion, I have included my observations on this as an endnote.)

The wood pellet boom is having a noteworthy impact on North Carolina. Our forests are being harvested for the pellets, several existing and planned wood pellet production facilities are located in the Tar Heel State, and much of their production heads to Europe through the Port of Wilmington. So is this trend a boon or a bane to North Carolina? The topics we need to consider before answering this question are listed below.

  • What are the greenhouse gas emissions impacts of wood pellets?
  • What parts of the tree are being used to make the pellets?
  • What is the impact on NC forests?
  • What is the economic impact on the state of NC as well as the communities where logging and pellet production occur?

In order to attempt to answer these questions, I have drawn from the website of the U.S. Industrial Pellet Association (USIPA), a pro-wood pellet lobbying association, and the Dogwood Alliance, an environmental lobbying group which is opposed to wood pellet production. Also, as is always the case, I am drawing from my own engineering judgment; thus, any errors in that arena are my own.

What are the Greenhouse Gas Emissions Impacts of Wood Pellets?

Fossil fuel use contributes to global warming and ocean acidification by extracting carbon from outside of the biosphere and releasing into the air as carbon dioxide. In contrast, burning biomass such as trees, grass, or manure does not introduce additional carbon into the biosphere. From this limited perspective, all biomass fuel options have a leg up on coal, petroleum, or natural gas. However, biomass fuel sources come with some further complications. For example, as I explained in Ethanol, It’s Not Just for Breakfast Anymore, you have to use approximately 1 Btu of fossil fuel energy to make 1 Btu of ethanol energy. Therefore, the production of ethanol serves more as a mechanism to provide subsidies to industrial agriculture companies who grow corn than as a true source of sustainable energy.

When considering the greenhouse gas impacts of a particular biofuel one needs to consider the balance between the rate at which carbon dioxide which is being removed from the atmosphere while the biomass is growing and the rate at which carbon dioxide is being released when you burn that biomass. For example, let’s say we were using a field of grasses as a fuel source. First, the grass is harvested and burned for heat. Then, after the grass grows back to its previous height, the amount of carbon dioxide that was produced as it burned has been recaptured and incorporated back into the grass. Since the lag time between cutting the grass and its full regrowth is short, using grass as fuel is effectively greenhouse gas neutral. (Please note that I am ignoring secondary factors such as carbon sequestration in the soil for simplicity.)

Using trees as a biomass fuel source presents the complicating factor of slow growth. Therefore, when trees are used as fuel, it is quite easy and often tempting to cut them down faster than they can regrow. When this happens, the amount of carbon dioxide in the air increases. According to the USIPA, net deforestation in the Southeast is not occurring, at least not yet. I did not find any arguments to the contrary on the Dogwood Alliance’s website, however, there are some additional subtleties about tree harvesting that I will discuss below that require some additional examination. Below I’ll address why looking at the net amount of area occupied by trees may not tell the whole story.

What parts of the tree are being used to make the pellets?

The potential impact of the use of wood pellets on the Greenhouse Effect, is strongly influenced by which parts of the tree are incorporated into the pellets. For example, if you use the trunk for lumber and make pellets from just sawdust and branches, then much less carbon dioxide is released compared to burning the whole tree.

If you look at the Sustainability tab of the USIPA website, you will find the following statements. The question, “What goes into a typical pellet?” is raised. And the answer given is, “mill residue, tops and limbs, thinnings, and low-quality wood.” This answer implies that whole trees are not typically used in wood pellets.

The Dogwood Alliance disputes the USIPA claims and asserts that whole trees are the primary feedstock for wood pellets. To back up this claim they include aerial photography of wood pellet manufacturing sites showing large piles of whole trees awaiting their turn to be turned into pellets. In addition, the Dogwood Alliance shows pictures from the websites of several large pellet companies which clearly show whole trees being staged as raw materials for the pellets. The text on these websites also suggest that whole trees are being used.

I find the data presented by the Dogwood Alliance that whole trees are being used to be convincing. Furthermore, it seems hard to imagine that power plants in Europe, which need a consistent and substantial fuel supply, could be adequately supplied from just sawdust and twigs. The volume of biomass with this approach would be quite low and it would also be seasonal since the amount of sawdust generated would ebb and flow with fluctuations in home construction in the U.S.

What is the impact on our NC forests?

A key risk in using wood as a fuel is deforestation, which results in loss of wildlife habitat, soil erosion, and decline of surface water quality. So is deforestation happening here? The USIPA has two statements on their website which address this question. They are, “U.S. Forests are not being clear cut for the Industrial Pellet Industry”, and, “Net growth of forests in the southern U.S. far exceeds removal.” Countering this perspective, the Dogwood Alliance provides data from the United States Forestry Service that healthy, diverse forests are being converted to pine tree plantations. According the Forestry Service, pine tree plantations covered 2 million acres in the 1950s and cover 40 million acres today. Pine tree plantations are a monoculture, which provide far inferior habitats for wildlife than a true forest.

I don’t have data on the conversion of forestland in NC into pine plantations. However, based on the national data from the Forestry Service it seems quite likely.

What is the economic impact on the state of NC as well as the communities where logging and pellet production occur?

The growth of the wood pellet industry in North Carolina is contributing to increased economic activity both in terms of increased capital investment and in the creation of manufacturing jobs. As such, the McCrory administration has welcomed these developments.

The economic impact on individual communities is a more difficult question to assess. Industries that solely extract raw materials compared to those that add value to raw materials through further processing create far less wealth. For example, locations where oil is extracted do not do as well as locations where oil is refined into value-added products. From this perspective, having a wood pellet processing facility, which adds value to the raw timber products, is better than simply having your forests harvested.

The risk for local communities stems more from the timber harvesting and transport activities. Communities need some protection against the problems associated with deforestation that I listed above. For example, tree harvesting near water ways needs to be carefully managed. Also, there should be some provision to reimburse local communities if increased traffic of heavy timber equipment causes damage to local roads.

Conclusion

After sorting through these topics it seems to me that the wood pellet industry is a more of a bane than a boon to North Carolina. As the Europeans continue to build wood pellet burning power plants, demand will rise so the price will rise. This will provide stronger incentives over time to cut more and more timber in North Carolina, adding to the greenhouse effect and degrading the quality and likely the extent of our woodlands.

I should point out, however, that it is not impossible to run a sustainable wood pellet industry, but this would require strong regulation and consistent oversight. Unfortunately, the way that the current administration in North Carolina has been handling environmental issues such as fracking regulation and ground water protection does not give me confidence that the wood pellet industry will be regulated in an environmentally sustainable manner.

Jeff Danner talked about this week’s column on WCHL with Aaron Keck.

 

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Endnote:

Burning trees as a fuel is more of a 16th than a 21st century technology. The world and North Caroline would be better off if the U.K. was building solar and wind power electric plants instead of burning trees. However, they are not burning their own trees, their burning ours. The primary reason that the Europeans colonized the Americas was to exploit the land for its raw materials such as trees. In order to keep England rich and America poor, they forbade the colonies from developing wealth-creating processing industries. So we were allowed to grow cotton not make cloth or grow tobacco but not make cigars. This unbalance economic dynamic was a key driver in the American Revolution. Therefore, I find it to be rather ironic that 240 years later our former colonizers are harvesting our forests for fuel.