Tuesday, May 28

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Biogas in the San Luis Valley: EPA hopes that anaerobic digester at Mosca becomes a model for others

by Allen Best

If driving to the Great Sand Dunes National Park, you might remember Mosca as the place where you turn off. It’s a few miles south of the alligator farm.

A new enterprise has started taking shape at Mosca, inspired by the idea that change must happen at the grassroots.

That ambition recently got a substantial plug of $200,000 from the Environmental Protection Agency for purchase of an anaerobic digester.

The project, in its application to the federal agency, proposed to become a tourist attraction itself, a place where people could inspect the apparatus. The digester will use bacteria to break down organic matter, including potato residue from an organic distillery, in the absence of oxygen. Methane, the primary constituent of natural gas, results. The methane will, in turn, be burned in lieu of propane in the various elements envisioned for the former campus of the old Sangre de Cristo High School.

“The outputs of one micro-industry are the inputs for another,” explains the project proposal submitted to the EPA.

The anaerobic digester is a project of the San Luis Valley Local Foods Coalition. The coalition was among 11 organizations who received more than $2 million from the EPA to divert food waste from landfills.

“Keeping food waste out of landfills and converting it into fuel is a powerful tool for combatting the climate crisis,” said KC Becker, the EPA regional administrator, in a press release. She said the San Luis Valley project can be a model for other similar projects in Colorado and beyond.

Colorado seems to be short on major anaerobic digesters. The EPA doesn’t track that sort of thing. An individual with the Colorado Department of Public Health and Environment said Colorado has nothing comparable to what is being planned at Mosca but offered no other comment.

However, Big Pivots in July 2020 reported completion of a biogas project at Boulder, at that time the fourth in Colorado.

Landfill gas is harvested at Erie and Fort Collins, possibly elsewhere. A1 Organics has composting operations at several locations along the northern Front Range but does not produce biogas.

It’s hardly surprising that a project involving agriculture would come out of the San Luis Valley. The valley is home to 60,000 people, a triangle of high-elevation sunshine defined by the Sangre de Cristo and San Juan Ranges. That sunshine makes it one of Colorado’s most attractive locations for solar development, now only partially realized, owing largely to transmission constraints.

For now, agriculture remains the dominant commercial enterprise. Of the crops grown there it is best known for its potatoes. Of Colorado’s 57,000 acres in potato production, 52,000 are in the San Luis Valley.

One element of the plans in Mosca calls for a distillery using potatoes. This is to be in the gymnasium of the former school. The anaerobic digester that will process the food and other wastes will be in the area where students once sprinted the 100-yard dash and jumped broadly.

The gas that is harvested in this will be consumed on the campus. No attempt will be made to gather food from other locations, such as from Alamosa, about 10 miles to the south.

The anaerobic digester will produce the energy equivalent of 6.5 gallons of gasoline per day while treating a maximum of 15,831 gallons of water per day.

There are other components: the solar thermal, of course, but also a wood-chip gasification, part of combined heat and power.

Overseeing all this will be Nicholas Chambers. He is the executive director of the Valley Roots Foods Coalition and its offshoot program for this project, the Valley Roots Food Hub. The latter is a wholesale aggregator and distributor of local produce and value-added produce from area farms. The goal is to provide a link between local, small-scale farms and restaurants, institutions, and other customers across the San Luis Valley as well as other locations in Colorado.

Chambers lives farther up the road in Crestone, at the base of Challenger Peak and Kit Carson, both among Colorado’s 14,000-foot mountains. From that base he has been installing small, solar-powered anaerobic digesters for the last 15 years via a business called Living Arts Systems.

The specific technology, a fixed-dome biogas plant, is meant for backyard applications. They typically cost $10,000 to $20,000. If well managed, he says, such units typically produce the methane equivalent—the primary constituent of natural gas—of two gallons of gasoline per day.

Chambers believes development of biogas will expand substantially in coming years. He reports attending a conference in Las Vegas in late April where 400 people were expected. Instead, more than 1,000 arrived.

Anaerobic digesting, however, remains a difficult economic proposition. “What I learned was that even though the EPA is upping the game in scale, it is still small.”

Chambers brings an interesting back-to-the-land perspective. A Colorado native, he earned a degree in anthropology from the University of Montana but then lived in a teepee for a decade and apprenticed on a biodynamic farm in British Columbia. Biofarms aspire to generate their own fertility through composting, integrating animals, cover cropping and crop rotation.

Returning to Colorado 15 years ago, he has applied his knowledge of permaculture biodynamics and deep organics in a small mixed farm and homestead.

He has also been teaching part time in New Mexico at the biofuels lab at the Santa Fe Community College.

The application to the EPA says the campus at Mosca will include a wood-chip gasification system for processing heat that generates biochar.

Part and parcel of this project will be education. The pitch to the EPA describes the park at Mosca becoming an ecotourism destination of its own, working in synergy with the nearby national park. Tours will be offered, reports will be generated and Chambers will integrate what he learns into his teachings in Santa Fe.

 This article is from Big Pivots 60. Please consider subscribing to stay abreast of energy, water and other transitions in Colorado and beyond. Allen Best is a Colorado-based journalist who publishes an e-magazine called Big Pivots. Reach him at allen.best@comcast.net or 720-415-9308.

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