Turning woodchips into electricity

SARATOGA, Wyo. (AP) — In the not so distant past, it was not uncommon for sawmills to burn their waste products such as woodchips and sawdust in teepee burners.

One of these rusted relics still stands at the sawmill in Encampment.

The practice of burning timber leftovers ended in the 1970s when stringent air quality regulations were enacted, so the timber industry began turning their wastes into forest products such as particleboard and mulch.

Fast forward to the dawn of the 21st century. Sawmills still have to manage mountains of woodchips, but now they have an innovative way of turning a profit by turning their biproducts into bio-energy.

Clint Georg, one of the partner-owners of the sawmill in Saratoga, said burning wood to produce steam, in-turn spinning turbines to create electricity is only currently being done on a somewhat limited scale. Yet Georg believes the industry will grow as the economics of bio-energy improves.

“In a single day, we produce about 250 tons of biproducts. Not all of this are woodchips, but the majority of it is,” Georg said. “Some of what we produce goes to (the Eagle Valley Clean Energy power plant) in Gypsum, Colorado.”

Although Eagle Valley produces 11.5-megawatts - compared to the 1,426-megawatt coal-fired counterpart in Pueblo - it opens up a market for woody material and helps displace burning fossil fuels.

Another potential bio-energy application for wood biproducts is to turn woodchips into biofuel.

“The sexiest way to use wood is to convert it into a liquid fuel,” Georg said. “Unfortunately, right now this process is just not commercially viable.”

According to Forisk Consulting, there are three general techniques to convert wood biomass into transportation fuels.

The first involves exposing wood to high heat in the presence of limited amounts of oxygen or steam - a process known as gasification. This produces a gas mixture called syngas, which then can be converted into liquid fuels such as ethanol or diesel.

The second route involves breaking down cellulose and hemicellulose to constituent sugars using acids and enzymes and then using microbes to ferment the sugars to ethanol.

The third process involves heating wood in the absence of oxygen - a process called pyrolysis - to produce a complex liquid called bio-oil. The bio-oil can then be stabilized before upgrading and refining to diesel, gasoline or associated blend products.

“Whether or not this can be accomplished with wood is kind of a waterfall,” Georg said. “Maybe if fuel prices become high enough it could be economically feasible, but right now turning other products such as corn and possibly algae into biofuel is more viable than wood.”

One consideration of a sawmill operator is seeing the forest through the trees. In many ways, a healthy forest is a sustainable forest.

Wyoming’s forests provide clean water and air, wood products for sale, habitat for wildlife and offer visitors and residents a place for recreation and reflection. However, Wyoming is facing unprecedented impacts on its forestland from bark beetle, white pine blister rust, forest fires, invasive species and drought.

Approximately 12 million acres of Wyoming’s land area is forested.

Throughout Wyoming, all species of bark invasive beetles have impacted almost 4 million acres of forest since 1997. In comparison, fire has burned approximately 2 million acres since 2000.

The sawmill can help reduce much of the biomass left behind from dead or dying trees.

“If you take the loop over the Snowy Range you will see that the health of the forest is absolutely terrible,” Georg said. “What we are facing now in the forest, as it dies out, is eventually there will not be enough live seedlings to regenerate growth. Right now we are probably OK, but 10 years from now, who knows?”

Whether it is woody biomass covering the forest floor that fuel hot and deadly fires, or dead trees left standing that block the sun’s rays from reaching seedlings, all shareholders in forest management agree something has to be done.

“What we can do is to go out and clear the (bio-mass). With just the simple act of taking the dead trees out - which represents 90 percent of the trees in some areas - the regeneration process will happen almost overnight,” Georg said. “What is happening now is that we are changing the nature of the forest and nobody can tell you it will look like in the future. All anyone can say is it will be substantially different.”

The Saratoga sawmill celebrates its second anniversary in January. It employs approximately 100 workers with an additional 50 under contract as loggers and truck drivers.

The mill produces 80 million board feet of lumber annually, selling 2 x 4 and 2 x 6 studs nationwide.

It also puts its own biproducts to good use by using the woodchips to fire an immense boiler used to treat and dry the cut lumber.

“This has a ton of capacity and is state-of-the-art,” Georg said. “In fact it is so powerful, in order to treat our wood we have to idle the boiler down. Also, there is an opportunity here - depending on the cost - to put in electrical co-generation that would be enough to power our facility.”

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Information from: Rawlins (Wyo.) Daily Times, https://www.rawlinstimes.com