For years now people have been writing about the decline of the timber industry in this country. All kinds of factors have been blamed: bad policies out of Washington, D.C., recession, outsourcing, deforestation (due to insects and invasive plants), and so on.
Besides that, young people nowadays aren’t that interested in working in the timber business, insiders say. There is some concern over who will fill jobs in the future.
But there is a bright spot of potential in this picture: the push for wood-derived biofuels.
Woodlands in the U.S. produce about 370 million dry tons of woody biomass every year. This biomass includes:
- diseased and infested trees
- trees felled by extreme weather conditions like hurricanes
- “slash” – branches, limbs, and stumps left after timber harvesting
- understory – small-diameter trees, or “thinnings,” removed because they might serve as a “fire bridge” between forest floor and canopy
- mill residues – sawdust, bark, and “black liquor” (what’s left after cellulose fibers are removed from the slurry that forms paper)
- urban wood waste – discarded furniture, pallets, processed lumber, and yard and tree trimmings
Typically, a lot of this woody biomass is burned, left to rot, or put in landfills. But people in government and industry are seeing it as a great potential energy source.
A lot of liquid fuel can come from woody biomass – things like ethanol, methanol, and bio-oil. The production of bio-oil, or bio-crude, occurs through the process of pyrolysis.
What they do is heat the biomass in an oxygen-free environment. Because there’s no oxygen present, the material doesn’t burn; instead, it decomposes into bio-oil, char, and non-compressible gases.
Bio-oil multiplies the energy yield of biomass by 12 to 15 times. It’s clean-burning and bio-friendly (carbon-neutral). The problem, though, is that it’s generally unstable and corrosive. So they still have to formulate upgrades for it that would overcome some of the problems with its transportation and storage.
If you slow down the heating rate of pyrolysis, the major product is bio-char. Bio-char is also called torrefied wood (“TW”). TW eliminates some of the problems associated with bio-oil.
TW is a charcoal-like solid that’s water-resistant, non-perishable, and energy-dense. It can be stored for long periods, so its transportation costs are lower than those of green wood chips. And it definitely has a higher BTU value per ton than green wood chips. Its energy content is said to be comparable to coal.
When it’s used as a replacement for coal, it produces a lot less ash, and its sulfur emissions are low.
It’s still going to be a long time before bioenergy is truly competitive with petroleum-based fuels. A few years ago, Chevron announced that it was joining forces with Weyerhaeuser, whose name means “Big Timber,” to research ways to make biofuels commercially viable. Their emphasis was on ethanol, the production of which has been controversial.
Weyerhaeuser is also in partnership with Mitsubishi to explore bio-char production.
I don’t think anyone is surprised that these giant corporations are co-opting the biofuels industry. Only the big energy companies can offer the economies of large-scale operations that will get bioenergy off the ground, they say.