Tribes: Pacific Northwest

Pacific Northwest

Qualco Energy

“After you try to get milk out of it, you try to get electricity out of it.” - Andy Werkhoven, Werkhoven Dairy

An unlikely collaboration between the Tulalip Tribes and dairy farmers in Western Washington has led to a highly localized power plant providing one of the rarest renewable energy resources in the world.

It started with too much manure.

Cows at Werkhoven Dairy eating grass. All photos courtesy of Daryl Williams and Qualco Energy.

A Threatened Watershed
Tulalip, located north of the Snohomish River and just west of Marysville, WA, is home to 5,100 Tribal Members, 2,700 of which live on the 22,000-acre reservation. The Tulalip Tribes are comprised of the aboriginal Snohomish, Skykomish and Snoqualmie Tribes along with other allied bands that moved to the Tulalip Reservation formed under the Treaty of Point Elliot in 1855. Being on the coast and in such close proximity to the Snohomish River, the Tulalip People rely heavily on the watersheds for cultural and sustenance purposes.

Surrounding Tulalip are multiple dairy and monocrop farms. The rich soil, nearby water sources, and idyllic, moderate weather make the area perfect for agriculture. However, up until 2008, the dairies and farms operated under modern American farming practices, with production levels set as the highest priority. Forests were cleared in favor of larger fields. Manure from the dairies was applied directly to the agricultural fields, taking 12-18 months to finally break down into nutrients the crops could use. With Washington’s heavy rainfall and the farms’ proximities to the Snohomish and Skykomish Rivers, heavy nutrient runoff into the rivers occurred.

A map of Marysville and the surrounding Rivers.

Excess nutrient runoff into water bodies causes eutrophication, which causes mass die-offs of aquatic plants and animals due to hypoxia, a lack of oxygen in the water. Nutrient runoff from farms caused the Skykomish and Snoqualmie Rivers to be listed on the Washington State Department of Ecology’s 303(d) list for polluted water bodies. Water bodies on this list require a water improvement project before they can be taken off and can remain on the list indefinitely if a project is not undertaken. Given the interconnected river system in the Pacific Northwest, improving the health of one watershed would have major impacts on surrounding water bodies. Without a water improvement project, the health of nearby rivers could be expected to decline as well.

An Unlikely Partnership
In 2001, when the health of the watershed began to decline, the Tulalip People knew something had to be done. If the primary issue was nutrient loading, fertilizer and manure management practices had to change. For the first time in the Tribe’s history, they sought to collaborate with the farmers they rarely spoke to outside of a courtroom, typically in a lawsuit over nutrient runoff affecting Tulalip Tribal members’ abilities to harvest fish from the rivers. Both farmers and Tulalip Tribal members wanted to restore local waterways and wildlife habitats, as without healthy water bodies the Tulalip Tribal members would be limited in their subsistence harvests, and farmers would be challenged in finding ways to irrigate their crops. Higher nutrient concentrations in the water would interfere with crop irrigation as harmful algal blooms could lead to toxic water.

Manure management is one of the biggest challenges dairy farmers face and knowing that they may no longer fertilize nearby crops with raw manure meant that a creative alternative had to be found. The idea of an anaerobic digester was suggested, and while it was an emerging technology at the time, it was such an interesting and exciting concept that the Tulalip Tribes and 5 local dairies – including the Werkhoven Dairy - were onboard.

Anaerobic digesters are sealed, airtight tanks. In an anaerobic digester, bacteria break down organic matter and biogas is generated. While not of the same purity as natural gas pipelines, which contain nearly 95% methane, biogas ranges between 45-75% methane.1 Most of the remainder is carbon dioxide, though there are small amounts of hydrogen sulfide, water vapor, and trace amounts of other gases. Biogas can be purified to create renewable natural gas or can be burned like natural gas without purification to generate electricity and heat. After gas is removed during the digestion process, digestate is left behind. The digestate is incredibly nutrient dense (though exact nutrients vary based on what was digested), and after the solids and liquids are separated, they can be used for fertilizer and compost.

Diagram of Qualco Energy’s Digester Courtesy of Regenis. All photos courtesy of Daryl Williams and Qualco Energy.

The idea was that Werkhoven Dairy would provide the manure, and the biogas would be used to power a generator to provide a clean, local energy source to the community. And everyone would see improved watershed health.

Thus began Qualco Energy, named for the Lushootseed - a Native Language in the region - word meaning “where two rivers come together.”

A Rocky Start
The first step was to get funding for a feasibility study, which was obtained through a grant from the Department of Energy. The feasibility study came back and confirmed that an anerobic digester, and this partnership, were excellent ideas. The feasibility study would prove to be essential in securing funding for construction and implementation - a price tag of $3.3 million. $500,000 was awarded by the US Department of Agriculture Rural Development Program, and $2.7 million came from a renewable energy bond authorized by the IRS that essentially served as a loan. After completing a hefty amount of paperwork, construction of the 184 foot long, 74 foot wide, 1,452,000-gallon capacity underground anaerobic digester began.

It was 2008.

The uncertainty of the economy following the recession led 4 of the 5 dairies to pull out of the project. Fortunately, the largest dairy farm, the Werkhoven Dairy, was committed to Qualco Energy and the benefits it could provide the community and the environment. After one of the smaller dairies went out of business, the Werkhoven Dairy bought their farm, increasing the expected manure input for the anaerobic digester. Despite the fragile economy and the significant decrease in fuel for the digester, construction concluded in December 2008 and the anerobic digester was up and running.

Qualco Energy’s Anaerobic Digester. All photos courtesy of Daryl Williams and Qualco Energy.

How It Works
At Qualco Energy, manure is flushed out of the barns at the Werkhoven Dairy and pumped into a funnel where the sand from the cows’ bedding settles to the bottom. The manure continues to flow into a separator, where the solids are screened out to be sent to the digester, and the water is sent to a separate facility to be cleaned. Clean water from this process is used to flush the barn again, and dirty water is mixed with the solid manure and sent to the digester. When the sink tank is full, a pump turns on and sends the manure a mile and a half down the road from the Werkhoven Dairy to the digester.

In an open pit, each day 80,000 gallons of input materials are mixed and then pumped into the anaerobic digester. The digester is kept at a constant 100F by waste heat from the generator. Most biogas is sold to the Snohomish County Public Utility District, which is then used to power a generator that provides electricity to nearly 700 homes. This cleans the overall energy profile of the community. A small amount of methane is not sold to the Snohomish County Public Utility District, as it is pumped back through the digester to agitate it, maximizing biogas production. The rest is burned in a flare to breakdown the methane into carbon dioxide.

After 17 days, digestate is sorted so that large particles are removed, and smaller particles stay in the liquid stream, which is sent to a lagoon for further crop fertilization uses. Large solid particles are then pushed through rollers to compact them. The compacted solids are then sent to a compost facility. During the growing season, the material from the lagoon is pumped underground and connected to sprinklers that spray the effluent onto the fields. The crops can utilize these nutrients as they are applied. In turn, the nutrients are, not washed away during the numerous flood events that happen in the region each year.

The anaerobic digester operated by Qualco Energy is fueled almost exclusively with manure from Werkhoven Dairy and pre-consumer food waste. This food waste, from grocery stores, food processors, and local restaurants, is produced from overproduction, spoilage, or expiration, and is nearly 30% of the digester’s input, as this is the limit of pre-consumer food waste that Washington State allows in anaerobic dairy digesters without a solid waste permit. Tipping fees – fees paid by those disposing waste - from the pre-consumer food waste greatly contributed to paying back the $2.7 million dollar bond, and after 15 years of operation, Qualco Energy is nearly debt free.

With the bond completely paid off, Qualco Energy is seeking to expand operations and develop new partnerships.

The Future of Qualco Energy
Qualco Energy is currently limited in their production by digester capacity and herd size. Increasing herd size takes time, but so does the development and construction of another digester. Therefore, Qualco Energy hopes to have another digester online in 3-5 years, which will give Werkhoven Dairy plenty of time to expand to meet the demand of the digester. Given tipping fees from food waste, available grants, and the price they receive on raw biogas through a partnership with their local utility, Snohomish County Public Utility District, expansion is financially feasible. Qualco will also apply for a solid waste permit so they can take a higher percentage of food waste to make maximum use of the new digester. As the dairy grows its herd size, Qualco will reduce the food waste percentage to make room for the additional cow manure.

As renewable energy technologies broaden in scope and become more efficient, new technologies are being tried to add to the potential renewable electric load. One such technology is hydrogen, a clean, carbon free alternative to natural gas. However, hydrogen is an extremely limited resource, so finding new ways to obtain the gas is essential for it to be a reliable source of energy. The partnership between Modern Hydrogen and Qualco Energy seeks to do exactly this.

Modern Hydrogen aims to strip hydrogen out of the methane – which consists of one carbon atom and 4 hydrogen atoms - in the biogas produced by Qualco Energy’s anaerobic digester. The other gases in the biogas mix must be filtered out so that the methane can be stripped of its hydrogen. This pilot project will identify the challenges with removing hydrogen from a dirtier gas than pipeline grade natural gas and help determine whether it’s feasible. The biogas produced at Qualco Energy is only 50-65% methane, meaning that a lot of other gas needs to be filtered out before beginning to use pyrolysis to strip hydrogen.

After hydrogen is stripped from natural gas, it can be used as an energy source. The remaining carbon molecule leaves the pyrolysis process in a solid, granular form. The carbon is then conveniently weighed and mitigated greenhouse gases are measured. The granulated carbon has a place in a more sustainable future as well. By mixing it with concrete or asphalt, carbon-intensive construction industries can mitigate emissions. Additionally, preliminary studies show that mixing the granulated carbon into asphalt increases its strength and durability, so a thinner layer can be used on roads to get the same result as asphalt paving. Carbon is mitigated, and more durable, sustainable materials can be used in maintaining urban infrastructure.

With another digester coming online, and more digestate and fertilizer being produced, Qualco Energy hopes that truckers will be able to transport the liquid fertilizer on roads blended with the granulated carbon from biogas from their digesters.

What started out of a need to protect the watershed has blossomed into a vital combatant of climate change. Since the anaerobic digester at Qualco Energy came online, nutrient loading is no longer an issue in the Skykomish and Snoqualmie River systems – with the help of other farms changing their land management practices. Having the second anaerobic digester in the state was no easy feat, (the first was completed just a few months earlier) and, now that the learning curves have been smoothed out, Qualco Energy is playing an essential part in the renewable energy transition.

Inspiration and Optimism
Money was one of the biggest challenges Qualco Energy faced. Now, with all the available grant funding and the policy support behind renewable and sustainable energy projects, Qualco Energy is excited for the future of anaerobic digesters. Having large grants available for the upfront costs of an anaerobic digester may entice more farmers to build one. This introduces potential partnerships between farmers and Tribes - much like Qualco Energy - across the country.

Everyone in Tulalip benefits from clean energy and improved crop nutrient management practices. Anaerobic digesters are just one way to address these issues. Climate solutions can target not only large-scale issues, but local ones as well. Qualco Energy is a powerful example of relationship building and what can be accomplished when two different entities come together with a common goal of conservation and preservation. The creative opportunities that arise when others do the same are endless.

EPA. (February 2023). How Does Anaerobic Digestion Work? EPA. Available online from: [accessed August 10, 2023].

This profile was developed in 2023 by Taryn Bell, Institute for Tribal Environmental Professionals, Northern Arizona University, with financial support from the Bureau of Indian Affairs. The profile is available on the Tribes & Climate Change website: The tribal climate change profiles featured on the website are intended to be a pathway to increasing knowledge among tribal and non-tribal organizations interested in learning about climate change mitigation and adaptation efforts.

Special thanks to Daryl Williams for his assistance in developing this profile.

For more information please contact:
Nikki Cooley, Co-Director
Karen Cozzetto, Co-Manager