A First of Their Kind

This quarter’s Biomass Construction Update profiles a novel pipeline dairy digester cluster in central California, and a biomass thermal plant upgrade in Halifax, Nova Scotia.
By Anna Simet | December 30, 2017

Somewhere within a 10-mile radius of the Calgren Renewable Fuels facility near Pixley, California, a crew is busy excavating dirt—perhaps along the edge of a field, or across the road of a dairy farm—laying pipeline at a minimum depth of four feet, carefully and methodically forging its way to the ethanol plant. Eventually, around 20 miles of pipeline will connect 10 anaerobic digesters installed at 11 local dairy farms, serving as the gateway for biogas that will be upgraded and used for process energy and more.

As of early December, several miles of pipeline were already placed. General contractor Maas Energy Works chose local R&B Co. as its supplier. The company prides itself on sourcing equipment and services from the nearby community, and, on every job for which it is hired, Maas is putting people to work. Now a staff of 15, all are working on the Calgren project, and at any given time, upward of 40 are working on different aspects—the pipeline, the dairy digesters, the gas clean-up equipment at the ethanol plant. “Work is only being done at two of the locations now, so once we get into six [digesters] at one time, there will be lot more contractors,” says Doug Bryant, Maas Energy development manager.

Maas has made a name for itself in the Pacific Northwest—they are the dairy digester guys, and they have the portfolio to prove it. With 13 digesters online and 17 more in development, Maas has built the majority of the West Coast digesters constructed over the past decade. A major key to the company’s success has been not only its growing track record, but that they handle everything from grid interconnection to permits, financial management and construction, so busy dairy farmers take on little to no burden.

For the Calgren project, it was a matter of explaining to local farmers what the possibilities were. “Working with the ethanol plant, we went out and proposed to all of the local dairymen that Calgren would build digesters for them, and use that gas off the digesters to fuel the ethanol facility, which has a high appetite for natural gas,” Bryant says. “To be able to get some renewable natural gas (RNG) was very appealing to them.”

The Circle A and Robert Vander Eyk dairy digesters are underway, and anticipated to come online in the second quarter of the year, with two more to follow by the year’s end. Notably, the project is what Maas Energy Works believes is the first of its kind in the U.S. “There’s an Indiana dairy that injects some dairy biogas into the pipeline, but other than that, nobody has been able to do this across a large area,” Bryant says.

For Calgren Dairy Fuels, the cluster project is a demonstration just how far the ethanol producer has evolved in its renewable biofuel efforts in the past several years. Pixley Biogas, a two-stage, mixed plug-flow digester, was built at the site of Calgren and came online in early 2015. Waste from nearby dairy operation Four J Farms is piped to the digester, and the resulting biogas is used to create power on-site. “That was our first introduction to digesters,” says Lyle Schlyer, president of Calgren Dairy Fuels. “This new project is quite a bit bigger—I would call it a bit of a phase two, though we didn’t have it mind when we did the other one. But we did have a couple of other things that we wanted to do—we’re also doing a biodiesel project.”

Calgren is building the pipeline big enough to handle about two and a half times what it originally contracted for, according to Schlyer, and not only will the gas be used on-site, but sold to local utility SoCalGas. “We think it will be a little bit of, ‘once you build it, they will come,’ but we think there are advantages for more dairies in the area,” he says. “If we don’t help them do this, eventually, they will probably have to do it themselves, on their own dime. California is pushing pretty hard to see this done, so we see it as an ultimate benefit for the dairies as well.”

While Calgren could use all of the RNG at its ethanol plant, Schlyer says, by plugging some into the pipeline, it is taking advantage of some incentives offered in California, that encourage the capture of dairy methane. “It's backing up our gas-fired turbine generators, and part of the plan is to get that interconnection of our biomethane into the local pipeline, so we'll be able to get some to CNG fueling stations,” Schlyer says. “It's part of the same project.”

Work is also well underway at the ethanol plant, and is being headed up by primary design engineers SCS, Schlyer says. “The pipeline is in, and we’ve broken ground on the process equipment to clean up the biogas to pipeline quality, which is tough in California—very high standards.”

The cleanup equipment—designed by SCS, with sulfur removal by DMT Clear Gas Solutions, and CO2 removal via an Air Liquide membrane system—should be operational in February, Schlyer adds. The plant should be getting gas from the first digester in March. “The rest will follow,” he says. “We’re currently projecting our interconnection to the gas pipeline around September. These projects are all about team work, and we have a great team.”

As for the most challenging aspect of the project, Bryant says it’s simply the newness of the concept. “We’re venturing down paths that nobody has been, coming up with new rules, figuring out things with the county, the irrigation district, the dairymen—for many of them it’s a new concept—building all of the monitoring equipment, and everything else,” he adds. “Those are the challenging parts, but also the most exciting parts. We have broken ground on something that nobody’s been able to do yet, and we’re excited about it. We have really fun huddles figuring out how to solve certain problems, and we’re coming up with neat solutions to certain situations.”

Dalhousie University Thermal Plant Upgrade

Whether to replace the nearly 30-year-old heating plant at Dalhousie University’s Agricultural Campus in Halifax, Nova Scotia, wasn’t the question on the table when the project ball started rolling years ago—it was how the university could balance the facility’s renewal costs while supporting the community, connecting research and operations, and helping achieve Dalhousie’s carbon reduction goals.

What came together was a master plan that includes replacing the aging steam lines with hot water lines, switching out the wood boiler, installing necessary air quality controls, and, an add-on that will accelerate the payback for the university—a turbine to create electricity. 

Right now, the biomass cogeneration plant construction site is bustling, says Rochelle Owen, executive director at Dalhousie University Office of Sustainability. “We have already converted our steam system to hot water, that part is done. The biomass boiler and turbine are also there, and work is being done to get those set up and connected. At the same time, work is being done on the fuel bin, so there is a lot going on on-site right now.”

Planning for Dalhousie Agricultural Campus replacement system began when the provincial government was running the Nova Scotia Community Feed-in Tariff Program, which was designed to encourage community-based, local renewable energy projects by guaranteeing a rate per kilowatt-hour for the energy the project feeds into the province’s distribution electrical grid. The project received COMFIT approval in 2014, and the university plans to sell its excess power, expecting to generate around $1.36 million annually. “In our case, we were kind of lucky, because the community feed-in tariff rate has provided revenue stability for us to do this project,” Owen says. “If we didn’t have it, we probably would be doing a biomass boiler. It also secured our power purchase agreement that if wasn’t there, this project would be hard to do.”

Owen says the Organic Rankine Cycle turbine addition will add even more value to the system. “Our thought process there was that we wanted to make this whole system as efficient as possible—it is electrically led—so we actually reduced the size of the initial project. Our feasibility study was based on a high-pressure steam turbine that would create new revenue, but it would use more energy. So, we decided to take another look and make it energy efficient in the long-term. That’s when we went from steam to hot water, and actually changed out the whole distribution system.”

Now, the university is looking at innovative ways to use the waste heat it will have during shoulder seasons and summer, and plans to move forward with a study to explore options.

For fuel, the facility will annually use around 20,000 metric tons of biomass, which will be provided by local sources, and mostly consist of sawmill waste. “We have all of the contracts in place with our suppliers, and we did some innovation in that arena,” Owen added.  “Our fuel will be primarily saw mill residue, but we also created a category that we’re calling research fuels, so up to a maximum of 5,000 tons can be under that umbrella. It gives us the ability to pay a little more for that fuel, and help support innovation in that area. We have a contract with someone trying to grow willow for bioenergy, and we also have an agreement with three co-ops to do selective harvesting for product. Our goal there is to support their cause, to see if we can help get the cost down, and build more of a market for that supply. So we are paying more for that—we could have just used all sawmill residue, but this was another way to contribute to this sector.”

Owen said the goal was to finish construction by June, but the project is a bit ahead of schedule. “We’re hopeful it may be as early as May,” she said. “We’ve always had an aggressive target, and we're doing our best to move along.”

Author: Anna Simet
Editor, Biomass Magazine