Woody biomass is a catch-phrase tossed around a lot these days as the potential market solution that will help landowners economically manage their forests for forest health while also help solve our countries energy needs in the future. But is there really something of substance to talk about here? Wood biomass to energy has been the topic most in the headlines so this is a good place to start.
Burning wood as a source of heat is as old as the history of humanity and for many rural dwellers and landowners this remains an important source of income savings and even business venture. It possibly is the most economically viable biomass revenue stream currently in existence in Montana though it does not get much media attention. From a calculation based on personal experience I heat my house 99% with wood, burn approximately 720 ft3 or a rounded 6 cords of wood per year to heat my 1700 ft2 house and equivalent basement, which replaces my traditional oil furnace equivalent fuel oil cost of about $2500 per year. My firewood cutting costs are about $300 per year not including the initial cost of my pickup and chainsaw or my labor and occasional sore back. I could of course also deduct a monthly membership fee to a health club in lieu of working in the woods. If 20% of the 29,000 Montana forest owners (who own 10 acres or more) burn wood for heat and have similar specs as my house it would equate to 5800 homes that collectively save $12,760,000 per year, leaving more for discretionary spending on other things in the Montana economy. By the way, the official statistic for Bavaria Germany is that 30% of all households heat with firewood – which would pencil out to more than 300,000 homes and a savings of more than one billion $ as fuel oil there costs about double here. The downside to firewood in Montana is that many communities do not allow wood stoves because of air quality issues stemming from poor operation of wood stoves and burning wet wood. In Germany, stoves must meet specific efficiency and air quality standards, wood must be dried by law for a minimum of 2 years and chimneys inspected on a regular basis for creosote buildup – a sign of poor combustion and burning practices. An efficient wood burning system (technology, operation and maintenance) should show no smoke output other than during a brief cold startup period. So with that in mind, what other options for woody biomass are there?
Woody biomass markets other than firewood can be separated into two categories: with-bark or without-bark. This is an important distinction for markets because without bark requires pole sized or larger stems that can be run through a debarking system – which is an extra cost, requires a specific forest resource that may compete with existing sawmills and post and pole operations, and puts the end product in the same class as paper quality pulp. Alternatively, with-bark woody biomass would require a much less expensive processing cost and could include small diameter materials, brush, fire hazard reduction byproduct and slash piles or logging residue. The advantages of the later are that there is no current market for this material, there is a much larger annual harvest potential for this type of biomass and it currently is a cost to landowners and loggers as they must treat this material to comply with state fire hazard reduction specifications. Dry bark, in comparison to the wood underneath also has a higher per unit weight energy output when burned – though this may be compensated by the fact that small diameter and green wood is often wet and thus there is an energy cost in driving the water out of the biomass, and bark and needles have a more complex structure and chemistry than pure wood creating difficulties for secondary processing such as paper, fiberboard, wood pellets or chemical conversion. For these reasons clean chips (without bark) or pulpwood remains a much more viable product than simply woody biomass. For example – many of you have heard that Boise Inc. has started buying paper quality logs and chips from Montana for their papermill in Wallula Wa. – though that market may depend on the Asian markets continuing to buy wood from the west coast producers.
Burning woody biomass for electricity production, based upon experience and models from the United States and Europe has shown that it usually does not make economic sense as even in best case scenarios a wood to electricity plant produces electric power at a rate that is 3-4 times more expensive than existing fossil fuel plants. This should be obvious when one considers that woody biomass has less energy per pound, is more widely scattered across the landscape and thus requires more transportation, and needs more secondary processing (chipping and drying) than coal, fuel oil, or natural gas. Those facilities that do burn woody biomass tend to gain most of their economic advantage as cogeneration plants of both heat and power. Numerous wood energy plants across Europe heat entire communities with steam pipes, as do U.S. universities that have biomass based systems such as the University of Idaho, or Fuels for Schools projects across Montana. Electricity production is a byproduct that adds to the efficiency of the system but cannot pay for itself as a stand-alone product. This is why universities that heat their campuses with steam, and wood products processing plants that need heat for their lumber dry kilns or paper production are the logical outlets for woody biomass energy facilities. However, even when both heat and electric power can be captured, such facilities are at best break-even. The proposed University of Montana biomass project, that would have employed the most modern energy conversion technology available ultimately was canceled because estimated heat and electricity production with woody biomass would currently cost almost double what natural gas would. Stoltze Land and Lumber will be building a wood biomass energy system in the next several years because they have the wood biomass already on site and available, they can offset the cost of construction in part with needed upgrade costs they would have anyways and North Western Energy finally agreed to buy electricity at a fixed “green energy” rate – though only in a very limited quantity which allows for a relatively small biomass cogeneration facility. All told – burning biomass as an alternative energy source does not currently offer an economically viable stand-alone proposition for most scenarios – except of course as simple firewood for residential heating. There is after all a reason that many people in energy expensive and technologically advanced Germany still resort to firewood as an economically viable alternative.
Are there other alternatives for woody biomass? Greater interest is now focused on biochemical breakdown of woody tissue for multiple high value end products ranging from food flavorings and cosmetics to jet fuel. This past fall the largest ever USDA grant ($40 million) was awarded to the NARA project (Northwest Advanced Renewables Alliance) in an effort to take a pilot project involving Gevo Inc. proprietary yeast biocatalyst into full scale commercial production. A major end product of this process will be isobutanol, a four carbon alcohol that can be converted into an easily transported, noncorrosive “drop in ready” jet fuel. Gevo Inc. already has a nonbinding agreement with United Airlines to begin supplying biojet fuel to Chicago O’Hare International airport by 2013. Montana is also partnered with this grant and is already conducting logistics research as to where woody feedstock sources are readily available, potential processing sites, and transportation hubs for biorefined materials. Although the NARA project targets jet fuels, there are multiple other competing interests that can potentially use woody biomass for other conversion processes such as the start-up company Blue Marble biomaterials in Missoula that uses an acid, gas and ammonia targeted extraction technique to produce high value food flavorings as well as cosmetics, or the England based Green Biologics Ltd that uses Clostridia bacteria strains (the same non-oxygen loving bacteria that produces botulism toxin, tetanus and gangrene) to break down biomass for similar end products and that already has a pilot plant in Ohio and offices in Brazil, India and China. What biochemical breakdown techniques are looking at are the essential components of wood, which are cellulose, hemi-cellulose and lignin. The major building block of cellulose is the glucose molecule, which chemically bond together to form long molecular chains and one of the primary components of cell walls in the form of microfibrils. In the paper making process wood is disintegrated into these microfibrils and then recompressed into paper sheets. In the biochemical refining process, one of several techniques using acids, caustic, enzymes, yeasts or bacteria is used to break microfibrils into component sugar molecules, which are then reassembled using fermentation or other processes to produce high value alcohols, esters, thiols, and terpenes. Although the processes are complicated, many of these end products sell for hundreds of dollars per quart and are in significant demand on the international market. Isobutanol, the drop in jet fuel supplement would be a targeted byproduct of the process used to make higher priced products.
So what is the holdup? These processes are complicated where each tree species wood has to be matched with the appropriate and efficient breakdown method. Each step of the breakdown and reassembly process may end up being a separate business model requiring different facilities and permits. The bacteria, enzyme, yeast or other conversion processes are in the development stage in most cases, many involving bioengineered and DNA altered organisms, each of which is a closely guarded and proprietary secret. There are also different sources of sugar such as corn, sugar beets and sugar cane that are competing for a market share. An advantage that wood has is that depending on the species, it may contain more of the 5 primary sugars (glucose, mannose, galactose, xylose and arabinose) than other agricultural crops as well as complex useful secondary compounds. For this technology to move into mass production an attractive site for multiple processing facilities has to be coupled with an available and abundant source of sugar – or in our case wood. Site attractiveness will be evaluated based on a combination of social acceptance for this industry and the availability of different tree species, harvesting and transportation costs as well as processing potential of their different wood composition (for wood only, or wood with bark). In the case of the NARA project the research on social and resource factors along with the chemical extraction processes are scheduled to be completed within 5 years, with strong hopes that investor(s) will build processing facility(s) in Montana and be buying woody biomass close to the end of that time frame.
Where do these products come from right now? Most of today’s flavorings and cosmetics high end products that this industry is targeting are derived from the other most abundant source of hydrocarbons – crude oil and coal. As prices for these non-renewable commodities continue to rise, alternative sources such as wood may become more economically attractive. Also as awareness of the general public increases they may prefer to eat blueberry muffins with flavoring made out of tree extracts rather than crude oil.