The 2025 International Biomass Conference & Expo focused on innovation, policy, strategy and collaboration across the bioenergy industry sectors.
Caitlin Scheresky
Roeslein Alternative Energy is making big strides in the renewable natural gas space, as well as prairie restoration and wilfelife conservation. By
Anna Simet
Optimization Top of Mind
Industry experts offer insight and solutions for wood pellet and biogas producers to streamline their processes and maximize production. By Katie Schroeder
CONTRIBUTIONS
32 BIOGAS/RNG Hydrogen Sulfide Control for Biogas Plants: Balancing Efficiency, Cost and Sustainability By Lane Flora
Biomass Grants: Funding Your For-Profit Project By Joel Dulin
& DEVELOPMENT
Advancing Waste-to-X Technologies: Carbon Credit Opportunities and Sustainability Impacts By Ahmad Saylam
Feedstock Variability: Differences Among Biomass Anatomical Fractions and Tissues
By Bryan Donohoe, Yining Zeng, Xihui Kang and Ning
ANNA SIMET DIRECTOR OF CONTENT & SENIOR EDITOR
asimet@bbiinternational.com
Mulling Our Value Proposition
A week ago today, I was on stage at the International Biomass Conference & Expo in Atlanta, emceeing Biomass Magazine’s annual industry award ceremony and subsequent industry trade association presentations. While there is much I could say about what was discussed, I think the ultimate conclusion was that we, as an industry, are much stronger when we work together. That cliché, “A rising tide lifts all boats,” has never been truer. Many of the sectors within bioenergy and biofuels will have to adapt to changes and challenges under this new administration, the extent of which is murky at best. These segments of the broader bioenergy industry are connected, overlap or have similar goals or policy influences, and being on the same page is an optimal position for all. As I’ve asked my panelists every year, the question right now is: What is our collective message, and should we adjust it to align with new political interests? (I.e., we create value from waste, this is homegrown energy, there is security in renewable energy, versus, for example, sustainability and carbon benefits.) We are all of these things of course, but our strategy and value proposition may very well prove to be key during the next four years. Be sure to check out our general session recap, “Stronger Together,” on page 14, by Junior Staff Writer Caitlin Scheresky. We’ve also included some breakout panel coverage by Associate Editor Katie Schroeder, “Optimization Top of Mind” on page 26, which includes reviews of presentations chosen specifically for their focus on plant efficiency and optimization.
The final thing I’ll say about the conference, which had an excellent turnout with nearly 1,000 registrants, is that the conversation, networking, information sharing and expert insight were truly inspiring. Thank you to all who made the trip to Atlanta—our exhibitors, sponsors, speakers and attendees—we couldn’t do this without you, and we can’t wait to reconvene in Nashville next year and discuss the progress made in 2025.
As for our cover story, I was honored to interview Rudi Roeslein, founder of Roeslein Alternative Energy, about his career, company and continued aspirations. To say it was inspiring is an understatement. The first article I wrote for BBI International nearly 17 years ago, fresh out of college, was on Roeslein’s modularization company (they built a few ethanol plants), so it was extra compelling to learn about what motivated Roeslein to choose the path that he did. This includes the development of a very successful modularization company to launching into the renewable natural gas industry, to working toward restoring millions of acres of prairieland and wildlife habitats. As for his main reason regarding these continued, relentless ambitions with little financial motivation, Roeslein says, repeatedly and adamantly, “I just felt like it was the right thing to do.” You’ll find the full story in feature article “Mission Driven” on page 28—I hope you enjoy Roeslein’s fascinating story and a look behind the RAE curtain as much as I did.
2025 Int’l Fuel Ethanol Workshop & Expo
JUNE 9-11, 2025
CHI Health Center, Omaha, Nebraska
Now in its 41st year, the FEW provides the ethanol industry with cutting-edge content and unparalleled networking opportunities in a dynamic business-to-business environment. As the largest, longest-running ethanol conference in the world, the FEW is renowned for its superb programming—powered by Ethanol Producer Magazine that maintains a strong focus on commercial-scale ethanol production, policy, plant management, advancing technology and near-term research and development. The event draws more than 2,400 people from over 31 countries and from nearly every ethanol plant in the United States and Canada.
(866) 746-8385 | www.FuelEthanolWorkshop.com
2025 Sustainable Fuels Summit
JUNE 9-11, 2025
CHI Health Center, Omaha, Nebraska
The Sustainable Fuels Summit: SAF, Renewable Diesel and Biodiesel is a premier forum designed for producers of biodiesel, renewable diesel, and sustainable aviation fuel (SAF) to learn about cutting-edge process technologies, innovative techniques, and equipment to optimize existing production. Attendees will discover efficiencies that save money while increasing throughput and fuel quality. Produced by Biodiesel Magazine and SAF Magazine, this world-class event features premium content from technology providers, equipment vendors, consultants, engineers, and producers to advance discussions and foster an environment of collaboration and networking. Through engaging presentations, fruitful discussions and compelling exhibitions, the summit aims to push the biomass-based diesel sector beyond its current limitations. Co-located with the International Fuel Ethanol Workshop & Expo, the Sustainable Fuels Summit conveniently harnesses the full potential of the integrated biofuels industries while providing a laserlike focus on processing methods that deliver tangible advantages to producers. Registration is free of charge for all employees of current biodiesel, renewable diesel and SAF production facilities, from operators and maintenance personnel to board members and executives.
(866) 746-8385 | www.SustainableFuelsSummit.com
2025 North American SAF Conference & Expo
SEPTEMBER 22-24, 2025
Minneapolis Convention Center, Minneapolis, Minnesota
Serving the Global Sustainable Aviation Fuel Industry Taking place in September, the North American SAF Conference & Expo, produced by SAF Magazine, in collaboration with the Commercial Aviation Alternative Fuels Initiative (CAAFI) will showcase the latest strategies for aviation fuel decarbonization, solutions for key industry challenges, and highlight the current opportunities for airlines, corporations and fuel producers.
Please check our website for upcoming webinars biomassmagazine.com/events/webinars
or
The BioCharger® gives you the power to fight climate change by closing the energy loop so you can work o -grid to charge your vehicles, equipment, and power tools. Here’s how: The BioCharger eliminates and converts wood waste into electricity and transfers it to the Battery Storage Module (BSM), so you can recharge your battery-powered machines. The BioCharger, developed through a successful collaboration with Volvo Construction Equipment and Rolls Royce, is an eco-friendly, cost-e ective, renewable energy solution for today-and tomorrow.
From Biomass to Billon Dollar Carbon Removals Market
BY ELLIOT RENTON
As pressure mounts for businesses to decarbonize, many more are expected to rely on carbon removals to achieve net-zero goals, particularly in hard-to-abate industries such as data centers, shipping and aviation.
In fact, analysis by McKinsey suggests the carbon removals market could grow to $1.2 trillion by 2050, with early adopters such as Microsoft and Airbus having already bought into engineered carbon removal projects such as bioenergy carbon capture and storage (BECCS). For producers of biogenic CO2 (such as biomass and energy-from-waste plant operators who are prepared to install carbon capture), the potential new revenue stream is substantial.
It is often mistakenly believed that carbon capture technologies are new or there is little expertise in the field, but there is a vast amount of existing expertise to tap into from a catalogue of previous studies, projects and use cases. For an experienced team, delivering a BECCS project is not any more complicated or higher risk than other infrastructure assets. Indeed, there are already 45 commercial CCS facilities operating globally, and the United Kingdom has over 90 CCS projects in the pipeline.
Both CCS and BECCS will play a critical role in tackling climate change, creating jobs and boosting economic growth. This has led the U.K. government to make big commitments. Last October, £21.7 billion ($28.1 billion) in funding over 25 years was committed to make the U.K. an early leader in CCS and hydrogen. In December, this was followed with contracts signed to begin construction of the U.K.’s first CCUS scheme in Teesside, the East Coast Cluster. The U.K.’s second most advanced scheme, of which Evero’s first BECCS plant will connect to—Hynet in Cheshire—is expected to follow in its footsteps in early 2025.
As more CCS projects come forward, there will be an important distinction to be made between those that only offset carbon and those that remove it. When applied to a fossil fuel plant, CCS simply stops carbon from being emitted into the atmosphere—in other words, a carbon offset. However, when applied to BECCS, it permanently removes carbon from the atmosphere.
Fuel source selection is important. Wherever possible, waste wood should always be reused or recycled to maximize its monetary value and reduce its carbon and ecological footprint before being combusted to generate electricity. For example, with over a million kitchens replaced every year in the U.K., hundreds of thousands of tons of waste wood are created that have no other value or use to society. Previously, this waste wood would have been landfilled, but as the U.K. moves to eliminate almost all biodegradable waste from landfill by 2028, finding sustainable methods of disposal has become increasingly important. This has led to the
construction of several waste wood-to-energy plants. As an example, across its portfolio of assets, Evero Energy diverts around 380,000 metric tons of locally sourced waste wood from landfill to generate renewable electricity for over 125,000 homes annually.
With stable, high-quality cash flows underpinned by government subsidies, long-term power purchase agreements and fuel contracts, it is an infrastructure asset that performs well. And it also makes these plants ideal candidates for installing carbon capture and storage onto, with the sale of carbon removal credits poised to unlock a substantial new revenue stream. Indeed, the U.K. already has several such sites investigating or in the pre-front end engineering design (FEED) or FEED stages of applying CCS.
To fully unlock the potential of BECCS to produce carbon removals, there is a need for greater transparency, regulation and support within the market to attract investors and participants. Addressing this issue was a top priority for last year’s COP29 delegates, who agreed how carbon credits should be created, traded and registered. From this year, businesses will be able to offer carbon credits backed by the credibility of an internationally agreed standard.
Separately, the U.K. government intends to offer revenue support to spur investment in technologies such as BECCS and direct air capture by extending the Contract for Difference (CfD) scheme to incorporate greenhouse gas removals. This would create investor certainty using the same pioneering scheme that has successfully brought forward over 9 GW in renewable generation with a further 20 GW under construction or in planning. While the business model is currently in detailed design, the government has already confirmed that CfD contract durations will be for 15-year terms. Taken together, these actions are helping derisk investment in carbon removals so that large-scale projects like BECCS can be constructed to meet demand.
The future for biomass is changing at pace, with the pressure for businesses to decarbonize creating new revenue opportunities for those biomass plant operators that are prepared to add carbon capture. Along with growing government support, the case for BECCS has never been stronger. Ensuring transparent and sustainable fuel sourcing will remain central to the industry’s success, with waste wood plants offering a low-risk, environmentally conscious option for the application of CCS.
Author: Elliot Renton Chief Financial Officer, Evero Energy
Exploring the Immense Value of Forest Waste Utilization via Biomass Energy in California
Matt Dias, president and CEO of the California Forestry Association, was the guest on Season 4, Episode 8, of the Biomass Magazine Podcast. Dias, a forester and advocate for forest waste-derived energy, discussed the opportunity and challenges involved in connecting forest management and hazard fuels treatment with biomass energy facilities.
Tell us about yourself and the California Forestry Association.
Dias: I’ve been working in the forestry sector one way or the other for about 35 years now. I graduated from Humboldt State University in 1999 and worked in the industry in Humboldt and Santa Cruz County for the first 13 years of my career ... then I was successfully appointed with the state board of forestry and fire protection and ultimately ran that board for about 11 years. I’ve been with Calforests for about four years now ... I’m a registered, professional forester. Calforests is a true blue trade association—we repre
sent the forest products sector in California, and that comes with about 3.5 million acres of well-managed forestlands in California ... along with all the primary manufacturing facilities in the state—veneer plants, biomass facilities as well as primary manufacturing facilities in terms of traditional lumber.
Why do you and your organization work with, support and advocate for biomass energy in California, particularly forest waste-derived energy?
Dias: As with any organization similar to mine, we go through a strategic planning event every year, when we look at our needs for the individual year. Biomass utilization— forest waste utilization—in California has been a leading topic for quite some time, and this year, it is our number one topic in terms of trying to make changes within the legislative space of California to open up markets for biomass utilization. If you’re from California, it’s easy to understand the necessity of
wildfire prevention activities as well as wildfire recovery activities ... anyone across the nation can turn on the news in the summer months, and they’ll certainly see California on fire. It’s something we deal with on an annual basis. This past year, 2024, was noted as being a pretty modest fire season, yet some of our members lost 30,000, 40,000 to 70,000 acres of timberland. We’ve been very proactive on the wildfire prevention front, with the problem being that we’re treating lots of acres and creating lots of materials, but we have no outlets for that material. So, we’re storing it on the landscape or in piles, and in either one of those situations, it’s not working well in terms of retaining fuel on the landscape or changing our trajectory on the carbon front … we need to build out our biomass utilization in California, and that’s why we lean in so heavily.
Listen to the full podcast at www.biomassmagazine.com/podcast
Biogas on the Rise
A recent media brief explored the biogas industry’s successes in 2024 and examined policy influencing the future of biogas.
BY CAITLIN SCHERESKY
The biogas industry saw another record year in 2024, according to the American Biogas Council, which recently held a media briefing to discuss state-of-the industry, progress, potential and policy. Patrick Serfass, executive director of the ABC, led the briefing. The ABC represents all sectors of the biogas industry, from marketers and utilities to equipment retailers and nonprofits, boasting a wide membership of over 400 organizations and 6,000 individual members.
Starting from Scratch
The potential for biogas-produced energy in the U.S. is huge, according to Serfass, citing 1.4 billion tons of manure, 33 million tons of inedible food waste, and 1 million tons of wastewater biosolids as being sent to U.S. landfills each year, 470 of which are currently flaring their capturable gas. “This is why we exist—to recycle all this material,” he said. “We are not an industry that primarily exists to just make energy. There are lots of other industries that just make energy. Energy is actually a byproduct of what biogas systems do, and it’s where most of the revenue is generated from for these projects.”
The energy that Serfass referenced can be produced in several ways, starting with organic materials. Manure, food scraps and restaurant grease can go one of two ways—the landfill, where they will be broken down and converted into biogas-sourced energies like electricity, heat and renewable natural gas (RNG) by microorganisms, or a digester, which can produce materials like fertilizers and animal bedding or be reused as organic material for livestock and other agricultural purposes.
“A lot of the biogas systems compost their material after they digest it,” Serfass explains. “So, this is what we’re looking at here
... we’re creating an environment where those microbes can go to work and eat up all the organic material, make biogas, and [when the process is complete], you have the same nutrients that you started with—nitrogen, phosphorus and potassium. If it’s not at a landfill and is at a tank digestor, digested material is also produced, which can be used to displace synthetic fertilizers.”
Breaking it Down
As of 2024, 2,478 biogas capture facilities operate in the U.S., with 566 of those systems converting biogas into RNG and 1,418 producing electricity. Although there are biogas systems in all 50 states, Serfass said, there is still enough organic material available to build an additional 24,000 systems. “So, you can basically consider the U.S. biogas industry about 10% built out.”
With broad potential on the horizon, Serfass highlighted the success of the biogas industry in 2025, citing 125 newly live facilities, a 13% year-over-year (y-o-y) increase in biogas output capacity, and a 40% y-o-y increase in investment. “The main change for 2024 is that this is the first year that the farm-based projects or agricultural projects exceed the number of landfill projects,” he said. “And you can see if you look at the one-year growth ... that the growth of landfill systems actually did shrink. We had less growth in landfills in 2024 than we did in 2023, but overall, still a lot of growth.”
Biogas finds itself primarily used for power and RNG production, and Serfass noted a 5% increase in RNG production between 2023 and 2024. “Around 2023, we had about 35% of the projects ... producing RNG,” he said. “Now, it’s just over 40%.” Still, the majority of biogas output is used for power production and takes 59% of the pie, with the final 1%
representing facilities that flare their biogas. Some of these facilities, Serfass said, were built in the 1920s and still operate today.
Of the 125 new facilities built in 2024, 95% were built with RNG goals. “You can see that, clearly, the attention of the industry is focused on building new RNG projects,” Serfass said. “That’s mostly due to the economics of those projects. It’s easier to sell your gas as renewable natural gas than it is as renewable electricity right now.”
Capacity for RNG has increased by 170% over the past four years, Serfass said. In 2020, the total annual RNG output capacity reached 59 million MMBtu, with 64% of that capacity coming from landfills, 22% from agriculture, 9% from wastewater and 5% from stand-alone food waste. Total RNG output capacity for 2024 reached 159 million MMBtu, with 67% from landfill, 26% from agriculture, 4% from wastewater and 3% from stand-alone food waste.
Driving Forward
Following the industry snapshot by Serfass, the briefing transitioned to discuss policies moving the industry forward. Heather Dziedic, ABC vice president of policy, led the conversation. “Organic waste is everywhere,” she said. “This is not an urban rule or red or blue issue. You can see certainly where the density of projects exists across the nation, but also that they do not know political boundaries. And so, this is a really rare bipartisan issue.
“So, the way we look at policy around biogas systems is ‘how do we create incentives that build the recycling centers?’...Yes, energy, but also a bunch of other commodities and revenue opportunities,” Dziedic said.
Policies that encourage biogas capture grow market demand, support voluntary mar-
kets, encourage innovation and manufacturing, and grow supply, Dziedic said. “We focus on growing market demand, so really looking at diverting that waste out of landfills into more fruitful endeavors where we can produce commodities and fertilizers and energy out of that waste,” she said.
Dziedic highlighted opportunity in voluntary markets. “We know that corporates and other programs, whether that be driven by supply chains domestically or internationally ... are still committing, absent any policy mandates, to lower carbon products,” she said. “Whether that’s fertilizer or whether that’s energy, we know that voluntary markets are driving a lot of investment in this industry, and so anything we can do to support those voluntary buyers in their endeavor to buy RNG and biogas and other derived fuels is something we’re working on.”
Encouraging innovation comes next, Dziedic said. “The biogas systems themselves are capturing gas, but they’re also a great funnel for all of these other manufacturing and commodity production opportunities. And so, how do we encourage that, not only for the revenue stack to get these projects moving, but also for domestic economic growth?
“And then finally, how do we grow the supply? How do we grow what is being produced in terms of the actual fuel? That is really on the financial side—how do we give a leg up to the producers out there building these facilities and putting infrastructure and steel in the ground?”
Several federal policies are currently influencing the biogas sphere, Dziedic said, including the federal Renewable Fuel Standard and U.S. EPA Tailpipe Emissions Rule—both of which are up in the air under the Trump Administration. Similarly, financial policy has the potential to benefit the biogas industry, but requires revisions. “The ABC looks forward to working with the respective federal organizations to work toward industry-moving tax policy,” Dziedic added. “We have a ton of opportunity with tax credits. Because we touch so many facets of the energy sector, we are really looking to try and preserve and amplify what tax policy can do.”
TSI, Telfair Forest Products Build Torrefaction Plant in Georgia
TSI and Telfair Forest Products are proud to announce the construction of a torrefaction facility at Telfair Forest Product’s facility in Lumber City, Georgia. The partnership leverages Telfair’s operational excellence and TSI’s best-in-class biomass torrefaction technology to promote the growth of the nascent carbonized biomass industry.
At the facility, a Torreactor designed and fabricated by TSI will be paired with Telfair’s logistics for the torrefaction and densification of biomass to provide commercial demonstration samples for industrial users. The new facility, with a capacity of more than 15,000 tons per year, is designed to handle a wide range of temperatures and torrefaction levels. Construction is underway, with commissioning and startup in early 2025. (Submitted by TSI)
New Zealand Companies Sign MOU for Torrefied Wood Pellets
New Zealand-based power producer Genesis Energy has signed a memorandum of understanding (MOU) with Carbona to produce torrefied wood pellets, with the potential to replace coal with biomass at Huntly Power Station, according to New Zealand Energy and Climate Change Minister Simon Watts.
Huntly Power Station is New Zealand’s largest power plant, with a capacity of 953 megawatts (MW). The facility has been operating for more than 40 years and has units fired by gas, gas and coal, and gas and diesel. Genesis is considering trailing the use of biomass to offset coal and gas usage.
In addition to the MOU with Carbona, the company in February signed a term-sheet with New Zealand-based Foresta to advance negotiations on the supply of torrefied biomass to fuel Huntly Power Station. According to that announcement, Genesis is targeting a supply of 300,000 metric tons per year of torrefied biomass by fiscal year 2028. The company indicated it expects it will need to partner with several local torrefied pellet producers to provide the necessary volumes and supply chain resilience required to fuel the power plant with biomass.
Report: Chinese UCO Exports Fall Sharply in December
China’s exports of used cooking oil (UCO) reached a record high in 2024, but fell sharply in December after the Chinese government eliminated the 13% export tax rebate for UCO, according to a report filed with the USDA Foreign Agricultural Service’ Global Agricultural Information Network.
The U.S. was the top export market for Chinese UCO in 2024, at 1.27 million tons. That volume is up approximately 52% when compared to 2023, accounting for 43% of China’s total UCO exports in 2024. The country’s total UCO exports, however, fell by 60% between November and December after the government of China eliminated the export tax rebate.
The elimination of the UCO export tax rebate was announced on Nov. 15 of last year and became effective Dec. 1. According to a November 2024 GAIN report, the policy shift aimed to redirect China’s biobased diesel industry from an export-focused model to a more domestically oriented industry. The change is also expected to create export opportunities for sustainable aviation fuel (SAF) in China, as the European Union provisionally excluded SAF from proposed antidumping duties in July 2024.
The policy shift triggered immediate changes in UCO pricing, according to the report. Leading Chinese UCO producers set initial December and January contract prices at $1,000 to $1,050 per metric ton, an increase of $100 to $150 over previous rates.
In addition to the 60% reduction in UCO exports experienced in December, the GAIN report indicates that China’s UCO market slowed further in February due to declining order numbers and prices, traffic congestion and logistics delays. According to the report, many UCO traders are reluctant to sell at lower prices and are minimizing purchases to avoid losses from price fluctuations.
Despite China’s sluggish domestic UCO market, international demand for UCO has reached unprecedented levels, according to the report. The current domestic market slump in China is expected to be temporary, as growing international demand and tightening domestic supplies lead to a market rebound.
Aemetis Reports Improved Revenues For Ethanol, Biogas, Biodiesel Segments
Aemetis Inc. released fourth quarter and full year 2024 financial results on March 13, reporting increased revenues for its U.S. ethanol and biogas operations as well as its biodiesel operations in India.
The Aemetis Biogas subsidiary expanded its annual production capacity by 80% last year. Revenues were up by 139%. Amy Foster, president of Aemetis Advanced Fuels, said the Aemetis Biogas business is continuing to grow its operations. The company expects production capacity to reach 550,000 MMBtu this year.
According to Foster, the company has plans to expand its biogas footprint to 26 areas operating or under construction by the end of 2025, increasing production capacity to 1 million MMBtu in 2026. The company has completed the third-party verification process for seven California Low Carbon Fuel Standard provisional biogas pathways
The TSI Torreactor drum is installed at the torrefaction plant under construction at Telfair Forest Product’s facility in Lumber City, Georgia.
and expects final approval from the California Air Resources Board in March or April, Foster said.
The Aemetis ethanol plant in Keyes, California, is continuing efforts to improve cash flow and energy efficiency. As part of that effort, the company plans to install a mechanical vapor recompression (MVR) system. Foster said detailed engineering is now complete, with equipment procurement and off-site fabrication currently underway. Once operational, the MVR system is expected to reduce natural gas use at the Keyes plant by 80%. The company also reported that ethanol revenues were up 55% last year.
The Aemetis carbon capture subsidiary has received approval from the state of California to drill a characterization well. Foster said the first phase of drilling and installation of the conductor pipe for that well was completed last year. The company plans to use data collected from the characterization well to secure Class VI permit from the U.S. EPA, enabling the construction of a CO2 injection well and compression system at the site of Aemetis’ proposed renewable diesel and sustainable aviation fuel refinery in Riverbank, California.
Drax Reports 5% Increase in Wood Pellet
Production in 2024
Drax Group plc on Feb. 27 released full year 2024 financial results, reporting strong improvement in operational and financial performance for its North American wood pellet segment. Biomass power generation was also up significantly.
Drax produced 4 million metric tons (mmt) of wood pellets in 2024, up 5% when compared to the 3.8 mmt produced in 2023. Increased wood pellet production last year benefited from the commissioning of a 130,000-ton expansion of the Aliceville plant in Alabama.
The company said wood pellet deliveries during the year were weighted toward own-use contracts, which are more reflective of the current market value of long-term, large-scale supply than some legacy third-party supply contracts. In the company’s full year financial report, Drax Group CEO Will Gardiner said pellet operations “made strong progress towards its target in 2024 with improved performance and the development of new markets for biomass sales.”
Drax is working to develop a pipeline of sales opportunities in North America, Asia and Europe. The company considers sustainable aviation fuel (SAF) to be a major market opportunity for its pellet business. In its financial report, Drax referenced an agreement made last year with Pathway Energy LLC that could result in the company supplying 1 million metric tons per year to Pathway’s proposed SAF project in Texas.
Drax Power Station generated 14.6 terawatt hours of biomass electricity last year, up 27% when compared to 2023. Much of that increase was attributed to prolonged periods of low wind speed, which lowered wind generation, leading to higher demand for biomass power. The company said it is continuing to evaluate an option to add bioenergy with carbon capture and storage at Drax Power Station.
STRONGER TOGETHER
The 2025 International Biomass Conference & Expo focused on innovation, policy, strategy and collaboration across the bioenergy industry sectors.
BY CAITLIN SCHERESKY
Just under 1,000 biomass industry professionals convened in Atlanta, Georgia, March 18-20, for the 18th annual International Biomass Conference & Expo. John Nelson, chief operating officer at BBI International, welcomed the 998 registered attendees and 176 exhibitors, “making this our largest event in the past decade.” The attendees “represent 28 countries, 46 U.S. states and 10 Canadian provinces, with more than 215 registered producers,” he said, stating that the “true growth of this conference is in the quality of connections.
“This conference is more than just a gathering; it’s a hub of progress, innovation and collaboration ... we’re not just sharing a space, we’re creating a platform to exchange knowledge, explore new opportunities and advance the industry together,” Nelson said.
Tim Echols, commissioner at the Georgia Public Service Commission, took the stage to offer a few welcome words of his own. “We’ve got so many things going on in Georgia,” he said. “In Georgia, we are reliability-centric, then cost, and then carbon.”
Anna Simet, director of content and senior editor at BBI International, presented the Excellence in Bioenergy Award and the Groundbreaker of the Year Award. These awards are designed to help recognize those individuals and companies who have made significant accomplishments or contributions within the bioenergy industry, as well as inspire and motivate the next generation of leaders in the bioenergy industry. The Excellence in Bioenergy Award was awarded to Brian O’Connor of Air Burners Inc., and the Groundbreaker of the Year Award, went to SDI Biocarbon Solutions LLC.
IMAGE: EPNAC/BBI INTERNATIONAL
The Pellet Report
Executive Director of Pellet Fuels Institute, Tim Portz spoke on the 2024 U.S. domestic wood pellet sales. “2024 saw the lowest sales line for wood pellets domestically since the Energy Information Administration’s been tracking our sector,” Portz said, coming in at just over 1.5 million tons sold last year.
Despite what might seem like doom and gloom in the pellet industry, the industry’s value proposition sits at $600 million, Portz said. “Any chance I can get to rees-
tablish—for anyone willing to listen—the value proposition of wood pellet manufacturing, I like to take it, because it is an absolutely staggering amount of material,” he said. “You really can’t understand the scope until you stand in the wood yard and see the material that’s coming in, truck after truck.”
The pellet industry’s future looks promising despite the incoming challenges, but Portz said that the work will be worth it, listing three items to accomplish: push back on the regulatory war being waged on wood pellet production and use; preserve the wood pellet appliance tax credit; and
maintain support for key wood energy provisions within the Farm Bill. “I’m predicting a great return to strong sales in January,” Portz stated, “I’m sure that [the February Biomass Fuel Report] will show a return to more typical marketplace activity.”
Taylor Fitts, vice president of communications and external affairs at the U.S. Industrial Pellet Association, spoke to international pellet exports. “We have 33 operational pellet mills spanning 11 states; we export out of nine port facilities along the Gulf Coast and the East Coast; we support over 5,000 jobs; and last year we exported
(From left) Patrick Serfass, American Biogas Council; Paul Winters, Clean Fuels Alliance America; Carrie Annand, American Biomass Energy Association; Taylor Fitts, U.S. Industrial Pellet Association, Tim Portz, Pellet Fuels Institute; and Anna Simet, BBI International, pose for a photo after the International Biomass Conference & Expo general session.
a record of 10 million metric tons of pellets with a value of nearly $2 billion,” he said.
The United Kingdom serves as the largest pellet export market, said Fitts, followed by Japan, an emerging market, the Netherlands and Denmark; Fitts cited the countries’ supportive policies and coal-to-pellet transition plans as key to the symbiotic relationship. “We’re about 15 years old or so, and we’ve had a remarkable journey. If you go back to 2012 all the way to today, our production has increased fivefold all through that lifespan,” he said.
The pellet industry finds itself in a transitional period with significant potential to lead the charge away from fossil fuels. “When I think about the future of our industry,” Fitts said,
“the number one word that comes to mind is ‘evolution.’” This transitional period opens several opportunities for industrial growth, from rising U.S. and global power demand to the transition from fossil fuels in heavy industries.
All Things Biomass
Executive Director of the American Biogas Council Patrick Serfass recapped the biogas industry’s role in the renewables transition, noting several similarities between the former and the pellet industry in age, maturity and opportunity. Serfass discussed the role of influential policy, calling on the audience to “call your member of Congress ... there’s a lot of uncertainty, and if they don’t hear from you—if they don’t hear from us—they don’t know what to work on.” (For more
ENGINEERING POSSIBILITIES.
One of Annand’s presentation focuses was connecting forest management and wildfire prevention with biomass energy production. IMAGE: EPNAC/BBI INTERNATIONAL
on the biogas state of the industry, see “Biogas on the Rise,” page 10.)
Paul Winters, director of public affairs and federal communications at Clean Fuels Alliance America, spoke to the biomass-based biodiesel outlook for the coming year. California boasts the largest market for biomass-based diesel, which meets 9% of distillate demand, Winters said. “California has about 70% of its diesel supply [produced] as a renewable product,” he said. “All of the renewable diesel ... that is being produced or recorded in the United States is going to the West Coast.” The California market actually dropped due to market saturation, with the state’s Low Carbon Fuel Standard amendments facing delays.
Despite the drop in California, U.S. imports and exports of biomass-based diesel have seen increases since 2023, Winters said. The Trump Administration’s imposed tariffs are expected to complicate this, as Canada’s retaliatory tariffs directly targe biodiesel, soybean oil, canola oil and distillers corn oil, he explained. “Canada and the United Kingdom both launched in-
Serfass called on attendees to contact their legislators to make their voices heard.
vestigations into renewable diesel ... they are prepared to put tariffs on exports to the United States,” Winters continued. “Canada is our biggest trading partner, so the loss of that market, or the change in that market, is going to force the U.S. and Canadian producers to shift where they drop their fuels.”
Domestically produced-only feedstocks could impact the industry. “The investment is there, the capacity has been built,” Winters said. “All we are asking for is a little bit of policy stability, the opportunity to get the capacity that has been built up to production models and for our companies to be able to make good on the investments that they already made in the industry.”
Carrie Annand, executive director of the American Biomass Energy Association, concluded the general session’s list of speakers. Also touching on policy impact, Annand spoke to the ongoing California wildfires and any subsequent traction on the harvest and utilization of forest thinnings for biomass energy. “One of the last acts of the Biden Administration was to ... put out the 45Y and 48E final rule for the socalled technology-neutral law that replaced the old section 45 and section 48,” she said. “We—the biomass sector—have relied on
this program for 20 years ... and the Biden Administration said, you know, the eligibility of the biomass power sector is no longer guaranteed in this program.”
The new Trump Administration and its massive push of executive orders included good news for the bioenergy industry, as Trump ordered the Immediate Expansion
Tim Echols, commissioner at the Georgia Public Service Commission and a supporter of biomass energy in the state, delivered welcoming remarks during the general session.
of American Timber Production on March 1, which Annand said holds promise. The ABEA fully intends to take advantage of these opportunities, she said, starting with its partnership with the U.S. Forest Service to produce biomass power plants with RFS pathway applications. “We can look forward to seeing biomass power plants ... and at the same time, the RFS is a tool that can promote all these tools that the administration has,” Annand said.
These changes have little impact if the next generation doesn’t continue the work, which Annand said the ABEA worked to remedy by recruiting social media influencers. “Last year … we had a content creator campaign ... we [collaborated] with this company called Aspire, which works with content creators. We educated them about biomass ... and they put out their own Tiktoks, Instagram Reels and Instagram Stories on biomass and why it is important environmentally,” she explained. “What we wanted to do with it is appeal to a younger generation, and to a more environmentally minded group of people.”
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Winters discussed how incomplete guidance of the 45Z tax credit is impacting the biomass-based diesel industry.
IMAGE: EPNAC/BBI INTERNATIONAL
MISSION DRIVEN
Behind its passionate leader, Roeslein Alternative Energy is making remarkable strides in the renewable natural gas space, with focused efforts in prairie restoration and wildlife conservation.
BY ANNA SIMET
At the age of 76, Rudi Roeslein isn’t ready to hang up his hat.
Founder of Roeslein & Associates and Roeslein Alternative Energy, Roeslein puts the people at his company before almost anything, even the endeavors that have kept his nose to the grindstone for the past 35-plus years. He views his employees as invaluable and the lifeblood of his business’
successes, and that sentiment hasn’t changed as the payroll jumped from just over 100 people in 2001 to nearly 1,200 people today, with operations in the U.S., China, Brazil, the United Kingdom and Poland. “I’ve run it more like a family—more so than what most people recommend,” he says. “In my early days, I knew almost everyone. But when you have 1,200 people, it gets harder.”
Roeslein’s business dealings and continued aspirations extend far beyond any financial motive—he is genuinely, even gravely, concerned about the condition the Earth will be left in for future generations. As such, Roeslein plans to do as much as he can for as long as he can, sometimes feeling “like it’s a drop in the ocean,” but always reverting back to the mission. “With the little of difference
Rudy Roeslein, founder of Roeslein Alternative Energy IMAGE: ROESLEIN ALTERNATIVE ENERGY
that I’m making, sometimes I’m asking myself, ‘Why the heck are you wasting your time? You’ve spent so much time away from your family most of your life, why don’t you just focus on your wife, kids and grandkids, and your farm?’ But I can’t. I can’t sit on the sidelines when I have these ideas that I think will make a difference.”
With perhaps his biggest claim-tofame being in modular construction and game-changing innovation in aluminum can manufacturing, Roeslein, who exudes humility, has also become a big player in the renewable natural gas and prairie conservation space. He describes his journey as beginning with “good fortune,” being able to immigrate to the U.S. from Austria when he was eight years old.
The Makings of an Innovator
“I grew up in Salzburg, Austria, until I was eight. We moved from displacement camp to displacement camp—my parents were Yugoslav Germans, and after World War II, things in Yugoslavia got really ugly ... it’s a tragic story.”
The immigration path landed Roeslein and his family in south St. Louis, Missouri. “Everybody worked,” he says. “I started working at age 13. My grandfather worked. My grandmother worked as a cleaning lady downtown, and my mom worked as a seamstress—and we truly lived. You know what most immigrants do? They will come here and they’ll work really hard, and they believe that the opportunities they have been given are special. I’ve always felt that, and you know, I make no excuses.”
Roeslein attended Saint Louis University with his sights set on becoming a professional athlete. “I kind of went there because of soccer—I wanted to be a professional player and was majoring in engineering as a backup plan. Along the way, I figured out that I wasn’t really that good at soccer, and they weren’t paying that much money—I didn’t need differential equations to figure out I couldn’t raise a family on that.” Contrary to Roeslein’s opinions of his soccer skills, his 1967 NCAA Division 1 championship soccer team was inducted into the St Louis Soccer Hall of Fame.
Post graduation, with an engineering degree underarm, Roeslein went to work for companies including Container Corporation of America and GISMO, where he developed many modular concepts. In 1990, Roeslein spun off and founded Roeslein & Associates, where he and his employees designed, built and shipped entire modular, preassembled beverage can manufacturing systems around the U.S. and worldwide. “When most people pick up a beverage can, they don’t really appreciate that it’s actually rocket science,” he says. “We make cans, now after 35, 40 years of innovation, at 3,000 a minute as opposed to 300 a minute when I started. That’s 50 cans a second coming off our lines. We were able to do this with American technology, when everybody was leaving and lamenting how we couldn’t compete. I said, ‘Sure we can. We just have to give our people the right motivation and the right tools.’ Now, we build these modular systems in our factories and have shipped them to over 60 countries, with over 700 systems [shipped] around the world for the past 35 years. We became the premier dominant player in the aluminum can industry.”
Roeslein & Associates thrived for a solid decade, but that’s not say there weren’t challenges encountered along the way. “With the cyclical nature of the can industry, we’d almost lost everything twice in 2000, 2001,” Roeslein says. “I didn’t have any work for almost two years, but I carried all of my employees, by coming in and smiling every day, and challenging them to reconfigure our systems and make them more economical, more efficient and smarter. I felt a sense of responsibility to all those people. I really felt that we would come out of that, so I risked everything ... and we did. The past two years have been pretty rough again in the can industry because these companies all build out and then they kind of saturate the market and have to wait for a few more years.”
As for extending into new markets, prior to entering the renewable natural gas (RNG) space, some opportunities to build ethanol plants presented themselves.
Pursuing New Endeavors
In 2010, Roeslein & Associates entered
the oil and gas industry and completed two ethanol projects using its concepts of unitizing and preassembly. “We built one in Illinois and one in Indiana, and that’s what led us to the renewable space,” Roeslein says. “I was asked to get involved in Abengoa’s plant in Hugoton, Kansas, but I looked at the complexity and became really concerned that there was too much of a jump from laboratory to a small demo unit to a commercial system ... of course, history proved me right, and they did go bankrupt.”
Roeslein’s career led to frequent and lengthy travel around the world, with a significant amount of time spent in Europe and Asia, particularly China. “That’s kind of where I started seeing what was going on environmentally, and it scared me, having come from the pristine Alps of Austria to the rural areas of the United States—I’m always looking for wild places,” Roeslein says. “I just started questioning, how long is it going to stay wild when we have this population pressure? I’ve seen [the pressure] that it’s putting on our landscapes for wildlife and wild places, and water. We have a finite set of temperatures and parameters that we can live in, and as we continue to change those, we’re putting our planet under a lot of distress. The people who don’t believe that, I think, are just not facing up to the fact that we are contributing to it, and we need to do a better job of figuring it out. How do we balance what we need with what the planet wants to give us, so we can all survive?”
Fast-forward to age 65, and Roeslein was nearly eight years into an employee stock ownership plan when he decided, rather than retire, he would start pursuing opportunities in anaerobic digestion and RNG. These efforts were influenced by what he observed during his travels in Germany, as well as the company’s previous work in the drop-in liquid fuels space. With Roeslein and Associate’s recent development of distributed control power systems for their modular utilized systems, Roeslein saw the potential application in the energy sector, and with intentions to integrate his passion for wildlife and prairie restoration, Roeslein Alternative Energy was born. “I approached Smithfield foods in 2011, and
it took a couple of years to convince them,” Roeslein says. “They asked how much money I wanted, and I said, ‘I don’t want your money—I just want your crap.’ I spent $57 million proving on a number of the farms that what we wanted to do would actually work, as well as three years getting a pathway with the [U.S.] EPA—and the California market was long and painful.”
With Smithfield as RAE’s partner, the joint venture forged ahead to build 200 lagoons across the country. “Almost 90 of them are in Missouri, and we’re in Utah, Arizona, Texas, New Mexico, North Carolina and Iowa,” he says. “We’re still looking at other states that have these [manure] challenges.”
Following the partnership with Smithfield, global private equity firm TPG invested
in RAE, which ultimately led to RAE merging back with its parent company. “After a yearlong negotiation, they purchased a third of the company, and through that process, it gave me a real valuation on what RAE should be worth,” he says. “We had derisked all of this, we would own it, we would operate it, and we would get a revenue flow from the gas. It wasn’t going to be purely transactional, and we would develop our own technologies. We do everything—I don’t have to depend on any contractors, aside from some basic subcontract work such as civil works, and the lagoon covers.”
Despite the successes of the company’s anaerobic digestion and RNG endeavors, Roeslein admits to plenty of challenges. “We’ve had some terrible times,” he says. “We’ve had viruses with the pigs where I had no animals to produce manure, and in 2018, a terrible storm wrecked most of the barns where I had my assets. I was pretty despondent that day, thinking about another year of no income and people thinking I’m crazy. But still—I felt it was the right thing to do.”
Roeslein’s revolutionary Micro Biogas Upgrade System IMAGE: ROESLEIN ALTERNATIVE ENERGY
Knowing the RNG portion of the business would have peaks and valleys, Roeslein designed RAE’s foundation similar to what he
describes as a three-leg stool: renewable energy via RNG, ecological efforts through restoration of natural prairie grasses, and restoration of wildlife habitats from biomass crops similar to native ecosystems. “Our concept is this three-dimensional Venn diagram ... we want to produce energy, but we also want to look at the ecological services that we can provide, including cleaning water and addressing soil loss, and providing habitats for our critical wildlife and our pollinators, even our butterflies.”
RAE-led Horizon II will do just that, Roeslein says, and help promote his vision all in one effort. A partnership of over a dozen public and private entities and supported by a grant from the USDA Partnerships for Climate-Smart Commodities, the project is focused on demonstrating how farmers get environmental credit compensation and renewable energy revenue by planting prairie grasses and cover crops. “We’ve already established over 5,000 acres of prairie grasses and over 1,000 acres of cover crops that we will be using as a source of energy,” Roeslein says.
“I think [Horizon II] is the real solution. My dream is to restore 30 million acres of native grasslands around our streams and rivers, and improve the quality of our water while preventing soil erosion.”
Refining RAE’s Offerings
With continued motivation to innovate, in 2024, RAE debuted its revolutionary micro biogas upgrading system, which is designed to help producers of all sizes participate in the RNG market. Its development stemmed from Roeslein realizing how complicated and expensive interconnection could be for projects—especially smaller ones—thus, inhibiting some from participating. “I knew right away that the Missouri location was probably going to be one-of-a-kind,” Roeslein explains. “There are 2 million pigs. There are nine finishing farms, with the biggest one having 170,000 pigs and 17 lagoons, and the smallest one having around 50,000 pigs. So, the economics of scale for those are really, really good—a very significant amount of potential revenue can be created from these farms.”
Roeslein’s Venn diagram represents renewable energy production, ecosystem services and wildlife benefits.
IMAGE: ROESLEIN ALTERNATIVE ENERGY
But after studying markets in Iowa, North Carolina, Kansas and most other states, RAE concluded that there weren’t any similar-sized, single operations that would achieve the same economy of scale. “I kept telling my team that there’s a finite number of these large plants, so we have to be able to help the small farmer, and at a scale where it becomes economical,” Roeslein says. “Just like a car, if we can make 1,000 of them, the cost gets drastically reduced. So my goal was to be able to address the small farms that maybe only have 1,000 pigs or maybe a couple hundred dairy cows? Is there a way to have a single point of interconnection?
“Our gas purification systems are just part of the cost [of a project],” Roeslein explains. “There is an interconnect that we call Area 1,000. We have the piping to get from the various lagoons to their gas purification systems, and then piping from there to a single
interconnect. We’re moving only the refined gas and not CO2, which reduces the pipe and volume requirements by almost 40%.”
Roeslein says all participants share in the interconnection cost. The first one has been installed in North Carolina, and RAE has commitments for over 100 more of them. “I’m hoping that eventually, we have thousands of these little systems like people have generators at their homes,” he says. “What if we had thousands of little distributive energy systems all over the country, and our energy systems could serve the local community and the bigger cities? You know they’re going to need gigawatts, but the small farms and the small rural communities can work on, you know, 5 to 10 megawatts. We can produce that if we use our Horizon 2 [model] where we also use other substrates besides just the manure. We believe that we can multiply the amount of gas produced by the animals by three or four
by adding cover crops and prairie grasses, and combining them in a way that actually makes those projects financially viable.”
Paving a Way Forward
As for his outlook on the RNG industry, Roeslein sees many opportunities beyond transportation fuels. “There’s LNG that we can ship, and I think there are other countries like Japan that would like to blend our low-CI score RNG with natural gas and get to net zero,” he says. “I think that’s a big step away from some of the other fossil fuels that have much bigger carbon footprint. RNG is a great movement going forward, because we have to deal with our waste. Why let all this stuff go into our atmosphere when we can use it, and it’s a big improvement over coal and most other fossil fuels?”
Roeslein doesn’t like to refer to himself as an environmentalist because of the often-negative connotation. “But I’m concerned about our environment and having a healthy place for our grandkids and future generations,” he says. “Every day when I wake up I say, ‘Okay, what more can I do today?’”
His message to the RNG space is that it still has a long way to go to reach its potential. “This industry is going to keep learning,” he adds. “It’s going to keep innovating, and somewhere along the way, we’re going to come up with a way to produce energy that doesn’t have unintended consequences. We’re on our way to doing that, but we have to keep working at it, and somehow, someway, educate people about the benefits of renewable natural gas and how it can be a bridge to wherever we go in 20 or 30 years. We can’t keep gobbling up landscape and doing things with photovoltaics and these giant windmills. It all has unintended consequences.”
For more formation, visit www.roeslein.com and www.prairieprophets.com.
Author: Anna Simet Senior Editor, Biomass Magazine asimet@bbiinternational.com
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OPTIMIZATION TOP OF MIND
At the 2025 International Biomass Conference and Expo, panelists offered insight and solutions for wood pellet and biogas producers to streamline their process and maximize production.
BY KATIE SCHROEDER
Optimization and efficiency are critical to biomass producers seeking to further decrease their emissions, save on operating costs and increase process yields. The International Biomass Conference & Expo, held March 18-20 in Atlanta, Georgia, featured panels of industry experts that offered process expertise, information on new technologies and more.
Enhancing Anaerobic Digestion
Titled “From Feedstock to Microbes: Enhancing Anaerobic Digestion for Optimum Performance,” a panel of biogas in-
dustry experts discussed strategies for improving anaerobic digester (AD) output and opportunities for AD to expand. Moderated by Ron Pagel, senior client manager and senior project manager Pond and Company, the panel included Chris Thomas, vice president of public affairs at Divert Inc.; Tim Cole, CEO of EcoPartners LLC; Dimitris Chrysochoou, senior technical specialist at Tradeworks Environmental Inc.; and Amy Hall, director of sciences with Digester Doc LLC.
As a circular economy company, Divert is on a mission to keep food from being wasted, Thomas said. Unsold food makes up a total of 15% of U.S. methane emis-
sions; Divert works toward mitigating those emissions through prevention, donation and renewable natural gas (RNG) production.
The strategy for reducing food waste begins with waste prevention, Thomas explained. Working with food retailers such as Kroeger, Albertsons, Target and Safeway, Divert invents technological solutions to help identify problems in their supply chain, mitigating waste. “We also help them figure out how they can instead use that food to deploy it for communities in need,” he said.
Divert’s strategy puts people first and ensures that edible food waste is donated. Finally, the remaining edible food is used to
(From left) Jason Kessler, KESCO; Jobie Rossell, Rossell Automation Company; Chris Veley, Material Control Solutions; Jill Caskey, Solex Thermal Science; and Tyler Brown, Andritz.
produce RNG. Working with a network of over 7,500 stores, Divert hopes to have 30 facilities across the U.S. with 80% of the country’s population within 100 miles of one of their locations. Currently, Divert has 14 operational facilities with 27 in active development.
Thomas explained that Divert’s founders spent years developing a large national footprint and getting retailers on board, enabling the company to aggregate food waste in large quantities and thus avoiding prob-
lems that have faced other project developers in the past.
EcoPartners helps troubled digesters fix problems to attain consistent production. Cole outlined the company’s work in transforming the Culver Duck Farm digester in Middlebury, Indiana, from a financial drain headed toward shutdown into a productive and lucrative asset. Cole explained that EcoPartners leverages a “scientific, strategic approach” in managing digesters, using research and analysis to de-
termine what’s going on inside the digester. One tool EcoPartners utilized at the Culver Duck site was the Valkyrie instrument, which enabled the company to get readings on digester inputs in real time, a “game changer,” according to Cole.
Feedstock management is a crucial element in maximizing methane production, he said, and knowing the chemical characteristics and compatibility factors for each feedstock while balancing nitrogen, carbon and moisture content in the digester helps the microbes thrive, optimizing production.
“Certainly, as an entrepreneur, one of the qualities that I struggle with is patience,” Cole said. “I think one of the things that
Chris Thomas, Divert
Tim Cole, EcoPartners
you have to consider when talking about managing an AD system is that it’s alive. It’s not just a hard asset ... whatever goes in affects what comes out.”
Superbugs also played a role in boosting methane production, Cole explained. A superbug is a microorganism that is more efficient and less susceptible to change, meaning it can handle increased organic load rates and boost energy production as it replicates. After utilizing a combination of research, site upgrades, feedstock management and ecological monitoring, the methane output of the digester increased to 102% of engine boilerplate and now consistently operates at 96% of maximum engine output, he said.
Following Cole, Chrysochoou presented Tradeworks Environmental’s findings on optimizing anaerobic digestion of sewage sludge with a novel biotechnology. The proprietary Ydro Process increases the digestion rate and efficiency of AD. “The process consists of a microbial product, combined with process microbial pretreat-
ment along with data analytics, to optimize anaerobic digestion conditions,” he says. Chrysochoou described the circumstances under which the experiments were executed. The microorganisms found in the Ydro Process produce enzymes in the metabolic process that treat contaminants as food, transforming them into volatile fatty acids and biogas, he explained.
Chrysochoou described the Ydro Process as occurring in two main stages. First, in the facultative stage, microorganisms break down complex organic matter in a predigestion step for feedstock pretreatment, he said. Next, the anaerobic stage has enhanced kinetics that enable better production of methane and biogas. Overall, the study’s findings indicated that Ydro increased methane yield per gram of COD added by 87%, doubled methane produc-
tion, reduced viscosity by 41% (which reduces the need for mixing), and increased dewaterability by 10%, according to Chrysochoou.
To round out the panel, Hall presented “How to Kill a Digester in 10 Easy Steps,” walking attendees through the misconceptions and mistakes that could kill an AD. “When digesters go down, there are a lot of costs associated,” she said. “There are cleanup costs, there’s down time, there’s lost profits, and we’re trying to avoid all of that.”
The first misconception Hall warned against was an “ignorance is bliss” mentality, which views a digester more like a machine where an input equals an output, rather than a living organism. Producers must consider whether the feedstock they are adding benefits the microbes or harms them, she said. Hall advised against ignoring shifts in pH or temperature, explaining
Dimitris Chrysochoou, Tradeworks Environmental
Amy Hall, Digester Doc
that even relatively small changes can make a big difference to the microorganisms in the digester.
According to Hall, some actions that may harm the digester include adding feedstocks without testing them, removing solids, skipping pretreatment, not ensuring that the microbes are getting the necessary nutrients, forgetting that some organic compounds are toxic to microbes, shocking the system with bad operational practices, assuming that every digester and feedstock are the same, and relying on too little information instead of a variety of parameters. “Remember to think of this [globally], it’s a microbial community,” she said. “The food that we put in is very important and the conditions that it lives under are also very important.”
Automation and Innovation
The need for optimization is not limited to the biogas industry. Another panel, “From Automation to Artificial Intelligence: Modern Technologies for Operational Optimization” explored methods to improve the pellet mill industry. Moderated by Jason Kessler, president at KESCO Inc., the panel featured Jobie Rossell, engineer and owner at Rossell Automation Company; Chris Veley, president at Material Control Solutions LLC; Jill Caskey, global sales director at Solex Thermal Science Inc.; and Tyler Brown, segment manager at Andritz Feed & Biofuel.
Rossell opened the panel, discussing his team’s work in improving the pellet mill process by introducing automation, handling obsolete controllers and leveraging available technology. “Optimization is the process of taking something that you already have, like an existing facility, and tweaking and tuning to get the most out of it.” One way of tuning the process consistency is Proportional Integral Derivative or PID control, which works like a cruise control on a car, he said, explaining that PID can be used to manage bin levels, adjusting feeder speed dynamically and preventing abrupt level changes.
Determining what to do with an obsolete controller is another important decision, and Rossell walked producers through their options. Controllers that are manufactured in the 1980s, such as the Allen Bradley PLC 5 controller, should be immediately replaced, and the Allen Bradley SLC 500 controller may or may not need to be replaced, depending on the facility’s plans. Rossell explained that the Controllogix and Compactlogix platforms are a good option for replacement—both work as a modern option for a controller. He discussed some determining factors for pellet producers to consider as they weigh replacing an obsolete system. Replacement is the best option if parts are unavailable and the producer plans to upgrade their process and add automation. “If you are not making any changes to your system, it works well the way that it is and there’s not much room for optimization, then you probably should consider keeping the old system,” he said. “There’s not much of a need to upgrade, but you still may need to, depending on availability of spare parts. If you don’t have access to all your PLC programs, if you’re missing any piece
of that puzzle, then it puts you into a vulnerable place.”
Moisture meters, vibration analyses, hazard monitoring, spark detection systems and energy savings techniques can all contribute to optimization and safety, Rossell added.
Artificial intelligence (AI) constitutes another tool for pellet producers to increase process efficiency. Veley introduced the Teknosavo technology and explained how its AI capabilities can assist pellet producers in keeping their production lines running, enabling them to pay for quality rather than weight. The goal is to help producers save on fiber costs. Teknosavo’s TruckSmart technology offers data on moisture level, material density, weight and particle size, Veley said. Using laser technology, the system scans incoming trucks and creates a three dimensional model of the truck’s load, allowing operators to pay for the quality of feedstock they have received. “In 60 seconds, Teknosavo can tell you the diameter of every single log, the number of logs, the average diameter of the log from smallest to largest, loose volume, dense volume, percentage of bark, [and] percentage of wood,” Veley said.
Teknosavo’s innovation goes beyond feedstock acquisition—the company’s technology also gathers data throughout the pellet production process with technologies such as WoodSmart, ChipSmart and more, according to Veley.
Solex Thermal Science’s moving bed heat exchanger (MBHE) and heat pipe heat exchangers (HPHE) offer another option for pellet producers who are looking for a way to cool pellets in an energy efficient manner, according to Caskey. Solex’s vertically oriented MBHE heat exchanger cools wood pellets indirectly, using stainless steel plates cooled by a thermal fluid. As the pellets fall between the plates, the pellets are cooled via conduction. This system produces near-zero emissions compared to direct contact cooling used in an air pellet cooler, which requires all the air used to be treated and scrubbed prior to release—an energy-intensive activity, she said.
The HPHE also offers significant energy reductions, she explained. Rather than using the high volumes of air needed for an air pellet cooler, the HPHE uses pipes full of either water or glycol to cool pellets. Caskey explained that the HPHE utilizes up to 90% less energy because water is more efficient in transferring heat,
Breakout sessions at the International Biomass Conference were well attended and offered attendee engagement through live question and answer sessions.
IMAGE: EPNAC / BBI INTERNATIONAL
using conduction rather than convection. Other benefits of the HPHE include a low er carbon footprint, less maintenance costs and easily meeting emissions standards.
Advanced solid biofuels offer another option for optimization, explained Brown, who presented after Caskey. Andritz offers pellet producers process technology for making steam-exploded and torrefied pel lets. As the global energy transition contin ues, pushing toward zero carbon, the po tential uses for solid biomass are plentiful across multiple industries, with uses ranging from a direct replacement for fossil fuels in heat and power to a feedstock for sustain able aviation fuel and more, Brown said.
Torrefied pellets can be used as a coal replacement in cement plants or be used to make syngas, Brown explained, while steam-exploded pellets work as a drop-in fuel for coal-fired heat and power plants. Andritz provides technologies for both of these advanced biofuels process lines, he said.
The above were two of 28 breakout panels at the International Biomass Conference & Expo held in Atlanta, Georgia, March 18-20.
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Hydrogen Sulfide Control for Biogas Plants: Balancing Efficiency, Cost and Sustainability
Selecting the right hydrogen sulfide control solution is a critical decision for biogas plants to maximize effectiveness, minimize costs and support environmental and regulatory goals.
BY LANE FLORA
Removing hydrogen sulfide (H2S) is a basic operation of most biogas plants, because H2S naturally forms during the anaerobic digestion of organic matter. Treating this toxic, corrosive gas early in the biogas process is essential to protect equipment from corrosion, improve the quality of the finished biogas, protect human health and the environment, and comply with regulations.
Biogas plants use several common technologies, and sometimes multiple technologies in combination, to remove H2S. When choosing a technology for H2S control, there are several considerations involved and elements to understand about each general technology.
H2S Removal Technologies
The most widely used technologies for removing hydrogen sulfide in a biogas plant include adsorption, biofiltration and chemical scrubbing.
Adsorption, either through activated carbon or iron sponge, is a simple, cost-effective technology that works well for low-to-medium H2S levels—less than 200 parts per million by
volume (ppmv). Specialized activated carbons are also available when H2S levels exceed 200 ppmv but can be effective across a wide range of concentrations. Adsorption systems are generally compact and easy to maintain with periodic media replacement or regeneration.
Biofiltration uses bacteria to break down H2S compounds. It works well for moderate H2S levels (200-1,000 ppmv) but does require significant space, precise operational conditions and maintenance that includes careful monitoring of bacteria and pH levels.
Chemical scrubbing uses alkaline solutions to neutralize H2S into nontoxic compounds. While it is effective for high H2S concentrations (more than 1,000 ppmv), it does come with high caustic chemical purchase and storage costs, and disposal costs for the resulting liquid waste.
Basic Considerations When Choosing a System
To select an H2S removal system while ensuring efficiency, cost and sustainability, a plant should consider the following factors:
H2S load: The concentration of H2S in the biogas stream is the first consideration. Plants with high H2S levels (above 1,000 ppmv) may require chemical scrubbers or specialized activated carbon, whereas lower concentrations can be managed with biofiltration or activated carbon filtration.
Operational and maintenance requirements: Activated carbon is a low-maintenance, plug-and-play solution that requires only periodic media replacement. Biofiltration has greater maintenance needs, including consistent moisture, temperature control and ongoing microbial health management. Chemical scrubbers require the storage and handling of hazardous chemicals and frequent refills.
Space and infrastructure constraints: Biofiltration systems and chemical scrubbers need significant space and must be integrated into plant infrastructure. Activated carbon filters are compact and easy to install, making them ideal for plants with limited space.
Environmental and sustainability goals: Many plants prioritize technology that minimizes waste and energy consumption and supports carbon footprint reduction goals.
CONTRIBUTION: The claims and statements made in this article belong exclusively to the author(s) and do not necessarily reflect the views of Biomass Magazine or its advertisers. All questions pertaining to this article should be directed to the author(s).
Table 1: Checklist for ideal H2S carbon adsorbent
SOURCE: JACOBI CARBONS
Some activated carbon and biofiltration systems offer sustainability advantages because they don’t rely heavily on chemicals or fossil fuel-based materials.
Regulatory compliance: The selected technology must be able to help a facility meet local, state and federal air quality regulations regarding emissions to avoid fines, minimize liability risk and maintain community trust.
Activated Carbon: The Sweet Spot for Many Biogas Facilities
Many biogas plants use activated carbon in the form of granules or pellets to adsorb H2S. When the air containing H2S passes through the activated carbon, H2S molecules are trapped by the activated carbon due to its high porosity and surface area.
Activated carbon can remove contaminants through two primary processes: physical adsorption and chemical adsorption. Physical adsorption occurs through Van der Waals forces, where a contaminant is attracted to the carbon surface. This type of removal is dependent on the pore structure of the carbon and the physical properties of the contaminant of interest. Chemical adsorption occurs through a multistep process where a contaminant is first physically adsorbed on the carbon and then reacts with a chemically treated or modified surface. Chemisorption typically targets inorganic gas species that show good reactivity (H2S in the case of biogas). For an activated carbon to be effective towards H2S, it must possess a good balance of micro and mesoporosity and strong reactivity towards
H2S. Optimized pore structure ensures there is low diffusional resistance and that there is adequate space for physical and chemical adsorption to occur.
The ideal activated carbon for H2S treatment should be of high surface area and activation level as indicated by the ASTM D5742 activity test. Additionally, activated carbon should be stable in high humidity and complex conditions, as biogas is often saturated with water and volatile organic compounds from the digester or landfill. Facilities also should consider the feedstock or global warming potential of their H2S treatment technology with the demand to move to greener technology alternatives. Coconut shell-based carbons are an attractive option because of their low carbon footprint and renewability.
The Overall Goal: Minimizing Total Cost of Ownership
Perhaps the most important point to consider is the total cost of the technology. This includes analyzing both upfront capital costs and long-term operating expenses. Some solutions are less expensive to buy but more expensive to design, install, operate and maintain; therefore, all costs must be taken into account.
Treatment of H2S in biogas facilities is a simple economic equation and boils down to the dollars spent per pound of H2S treated. For this reason, activated carbon should have a high capacity for H2S at a relatively low cost. Another operational metric related to cost is energy consumption of the treatment
technology. While fixed-bed adsorbers are relatively free from mechanical input, they do require fans and blowers to move gas through the bed. The size and energy consumption of these fans is directly related to carbon geometry. Pelletized carbon, typically with 4 millimeter (mm) diameter, offers the lowest pressure drop and energy consumption per foot of media fill. This can contribute to significant cost savings compared to granular media of 4x8 mm or 4x10 mm mesh.
Pellet geometry also offers high mechanical strength and robustness during installation, operation and removal, further extending the cost savings through initial fill and spent media removal. Activated carbon should exhibit a high hardness value per the ASTM 3802 test. These factors all contribute to the total cost of H2S treatment in a biogas facility, so it is important to check all the boxes when selecting an activated carbon adsorbent.
Selecting the right H2S control solution is a critical decision for biogas plants to maximize effectiveness, minimize costs and support environmental and regulatory goals. Common options include biofiltration, chemical scrubbers and adsorption. By calculating the total cost of ownership for every alternative that is a possible fit for a plant, an organization can make the best choice for both short- and long-term needs.
Author: Lane Flora Applications Engineer, Jacobi Carbons www.jacobi.net
Biomass Grants: Funding Your For-Profit Project
The specifics of a project ultimately determine available grant funding.
BY JOEL DULIN
It’s no secret that the United States government funds biomass projects. Uncle Sam awarded $574.8 million in 2024 to for-profit organizations working with biomass. Of that, $560 million went to three energy demonstration projects, with the remaining $15.3 million going to 39 other projects with an average award of $393,000.
You may wonder, though, whether such generosity will continue. After all, President Donald Trump’s administration has been slashing agencies’ budgets with specific aim at federal aid.
Fortunately, while federal funds will not continue at the levels they have during the past five years, they are unlikely to shrink much beyond what was typical prior to the pandemic. Plus, there is available funding outside Washington, D.C., from state and private funders.
Current Policy on Biomass
The first reason why federal grant funding is unlikely to disappear is that the Trump administration does not oppose grants. During Trump’s first term, the government routinely granted more funds than what was typical during the Obama years, especially to for-profit entities (bail-out dollars during the Great Recession aside). Prior to the pandemic, Trump’s administration granted an average of $5.8 billion annually to for-prof-
its versus the $4.9 billion average of President Obama’s second term.
What bodes well for biomass is that it aligns with current administrative priorities—namely, domestic energy production, manufacturing and export markets. Moreover, the administration is also pushing for more timber sales on federal lands. It clearly backs the wood product market.
Of course, there’s no guarantee there will be many opportunities specific to biomass. Renewable energy, a main driver for biomass spending during the past four years, isn’t one of Trump’s priorities. Still, markets have changed, and opportunities
for biomass are expanding with the advent of industrial-scale biochar.
Federal Grant Programs for Biomass
For these reasons, federal biomass grants will probably continue to some degree. A few programs under which biomass projects will likely remain eligible include:
• U.S. Forest Service Wood Innovation Program
• U.S. Forest Service Wood Products Infrastructure Assistance
• USDA Rural Development Program
• U.S. Department of Energy: various research grants
CONTRIBUTION: The claims and statements made in this article belong exclusively to the author(s) and do not necessarily reflect the views of Biomass Magazine or its advertisers. All questions pertaining to this article should be directed to the author(s).
Figure 1: Federal grant allocations to businesses increased during the pre-pandemic years of President Trump’s first term.
• Various agencies: Small Business Innovation Research Program
Other Funding
Among states, grant availability varies. Each state has unique priorities and approaches to economic development. Many offer job creation tax credits. Many also offer incentives to growing markets, such as biofuels. Still, others generally encourage manufacturing and other industrial activities.
Private funders are another source for grants, though to interest them, your organization must be strongly mission-driven or deliver definitively positive impacts. There’s also the challenge of eligibility. Most private funders limit funds to nonprofits.
Don’t let this discourage you, because you can work around the requirement by applying for a grant through a fiscal sponsor. Fiscal sponsors are nonprofits that take on the responsibility of administering a grant—doling out funds, completing reports, etc. As such, they receive the funds and funnel them to you. The catch is that the fiscal sponsor will likely take a large portion of the funding to cover their risk and administrative costs.
Another possible workaround is to partner with your local government or area’s economic development corporation. Again, these organizations would receive the money and manage it but may not require a steep overhead fee.
Discovering Grants
When you search for funding, it’s helpful to look beyond the word “grant.” Grants really include a broad range of programs that provide free or monetary incentives. These include traditional grants, tax credits, tax liability reduction, government-backed, low-interest loans and technical assistance.
Many tax credit programs work like grants in that you must apply for them and receive state approval before receiving
funds. It isn’t a matter of merely filling out a tax form. The same goes for programs that adjust tax liability.
Government-backed loans offer another route for project funding. Because they are less risky, lenders can offer them at below-market rates.
Technical assistance is also a form of grant, but instead of receiving money, you receive professional expertise or service.
How to Find Grants
As you search for grants, look through various lenses. Consider your industry. For example, look for grants that support manufacturing, biofuel or forest products. States tend to broadly label eligibility for economic incentives, which is why it’s good to take a macroscopic view of your project categories.
Next, consider the actual work your project entails. Are you managing biomass, or organizing a capital project? What you do is an important lens because many grants are characterized by their support for specific activities. Also, assess your project’s impacts. Funders look for projects that help them achieve specific goals. So, consider everything that your project positively affects.
Last, consider where your project is located. Many more grants will become available to you if you operate in a rural area or an area with high unemployment. There may also be grants available from or for your city or county.
Are You Ready for a Grant?
While researching grants, it’s okay if you’re working with back-of-a-napkin details, but when it comes time to apply for a grant, the following boxes need to be checked.
A location. If you can’t pin your project to a specific address, you aren’t ready to apply for a grant (projects designed to take place over a regional or geological area aside).
A team. You need a competent team to obtain any substantial grant. Funders rarely give money to individuals.
A timeline. Funders want milestones by which they can measure your progress, and to give them an idea of when they’ll need to expend funds.
A budget. By the time you write a grant application, you should have a firm grasp on costs. You should be able to back them up with quotes and research. Plan to account for equipment, employee time, contractors, overhead, travel, supplies and fees, among other measurable expenses.
Financial stability. If your business hinges on receiving a grant, I recommend pursuing other types of funding. Most funders provide grants on a reimbursement basis, meaning you spend money before receiving funds. So, if you don’t have enough cash to operate, a grant won’t help you. You may, of course, request to receive funds before you incur costs, but this is not the norm. For this reason, it’s best to think about grants as a tool to boost your return on investment, not as something that will make or break your business.
Partners and support. Spend time creating partnerships. Ideally, you should supply at least three letters of support per application, but it doesn’t hurt to have more. Beyond vendors, consider everyone who has a stake in your project and ask them to write a letter: buyers, city officials, associations and others.
Conclusion
The specifics of your project ultimately determine what grant funding, if any, is available for it. Your preparedness and project details such as location its impacts all factor into how many opportunities you’ll have available to you. To find them, you just need the right lens.
Author: Joel Dulin Jozana Grant Services, www.JozanaGrants.com
Figure 1
*Syngas composition of Case 3.
Advancing Waste-to-X Technologies: Carbon Credit Opportunities and Sustainability Impacts
A recent study highlights the comparative environmental and economic benefits of different thermochemical treatment methods for wood waste.
BY AHMAD SAYLAM
As the global demand for sustainable waste treatment technologies grows, energy, syngas and biochar production from waste emerges as a promising solution to mitigate climate change. The following study, “Advancing Waste-to-X Technologies: Sustainable Thermochemical Pathways for Biomass Valorization and Carbon Credit Potential,” explores the potential of biochar production through various thermochemical treatment approaches of wood as a representative waste type. Three distinct cases are evaluated: Case 1, involving the traditional and widely adopted pyrolysis process, with syngas being subjected to post-combustion; Case 2, incorporating partial syngas combustion; and Case 3, utilizing renewable energy-powered, hot inert (nonoxidizing) gases.
The results demonstrate that Case 1, despite producing biochar, falls short in terms of sustainability due to high carbon dioxide and nitrogen oxide emissions during the syngas combustion phase, which counteract the carbon sequestration benefits of biochar and disqualify it from carbon credit eligibility. In contrast, Case 2 offers a practical intermediate solution by reducing emissions and improving
energy efficiency while producing valuable syngas for biofuel and chemical production. Case 3 represents the most sustainable option, utilizing hot inert gases from renewable sources such as solar or wind energy and releasing no CO2 or NOX, thus offering a zero-emission solution. By integrating syngas reforming and renewable energy, both Case 2 and Case 3 significantly enhance the potential for carbon credit generation and align with circular economy principles.
It is crucial, however, to consider not only the CO2 emissions directly generated by the core thermochemical and chemical processes in waste-to-X (WtX, with X representing a variety of outputs) conversion, reforming and recycling, but also the emissions associated with producing the chemicals and materials required for these operations. Addressing these indirect contributions is vital to accurately evaluate the full carbon credit potential of WtX solutions and to ensure they deliver meaningful climate benefits.
This study underscores the importance of adopting advanced, holistic approaches to achieve authentic carbon-neutral biochar production, thereby contributing to climate change mitigation, enhancing resource efficiency, and
offering strong economic incentives for sustainable and clean climate technologies.
Focus of the Study
The world is increasingly seeking ways to reduce greenhouse gas emissions and transition toward sustainable energy solutions. WtX technologies have emerged as a versatile and promising approach, converting various waste materials into valuable outputs such as energy, fuels, chemicals and materials. These processes encompass a broad spectrum of waste types, including biomass, plastics, municipal solid waste and industrial byproducts. By generating renewable energy such as electricity or heat and avoiding methane emissions from the anaerobic decomposition of organic waste, WtX facilities contribute to climate mitigation efforts and the circular economy. However, the environmental benefits of WtX solutions are contingent upon minimizing emissions, including CO2 and pollutants such as dioxins or particulate matter, which can arise during the conversion processes.
This study narrows its focus to thermochemical treatment technologies for biomass, particularly wood waste, one of the most abundant and underutilized resources. These technologies, including pyrolysis, gasification and
CONTRIBUTION: The claims and statements made in this article belong exclusively to the author(s) and do not necessarily reflect the views of Biomass Magazine or its advertisers. All questions pertaining to this article should be directed to the author(s).
hydrothermal carbonization, are widely used for converting biomass into biochar, syngas and bio-oil. Biochar, produced via the pyrolysis of wood waste, is particularly notable for its dual role in carbon sequestration and energy generation. Its ability to store carbon for extended periods makes it a key component in long-term climate change mitigation strategies.
However, traditional methods of biochar production are often associated with significant emissions, particularly CO2 and NOX, during the syngas combustion phase. To overcome these challenges, recent advancements have focused on integrating renewable energy sources and implementing innovative process designs that not only minimize emissions but also enhance overall process efficiency. Beyond biomass, these principles can be extended to plastics and other waste materials, enabling their conversion and recycling into valuable chemical building blocks, fuels and other products.
Thermochemical Treatment Cases
This work evaluates three thermochemical treatment scenarios for wood waste, comparing their carbon credit potential and sustainability outcomes. By exploring these cases, it highlights some opportunities and challenges in achieving cleaner, more efficient WtX processes and underscores the importance of holistic approaches in the transition to a sustainable future. They are as follows:
• Case 1: Traditional adopted treatment involving drying, pyrolysis and post-combustion of syngas to generate heat.
• Case 2: Adjusted treatment with partial combustion of syngas to supply energy for drying and pyrolysis, while reducing emissions.
• Case 3: Adjusted treatment using hot inert gases driven by renewable energy, eliminating the need for combustion and minimizing emissions.
We analyze the credibility of carbon credits generated by these processes, emphasizing the potential for CO2-neutral production and carbon offsetting that these technologies can offer.
Results and Discussion
The study compares emissions and production parameters of the three scenarios for processing 100 kilograms per hour (kg/h) of wood waste under the following conditions:
• Wood composition: Typical composition of 50% carbon, 6% hydrogen, 44% oxygen (dry matter) and 15% moisture.
Key Advantages of Cases 2 and 3:
1. Emission control and carbon neutrality in Case 2: Partial syngas combustion balances emissions and energy needs, offering improved carbon credit potential.
2. Zero emissions in Case 3: Renewable energy-driven inert gas pyrolysis achieves the highest sustainability by eliminating combustion-related emissions.
Conclusion
As the global demand for sustainable waste treatment technologies continues to grow, biochar production from wood waste, as a representative waste type, presents a promising approach to mitigating climate change. This study evaluated three distinct thermochemical treatment methods for wood waste, focusing on their potential for carbon credit generation and environmental sustainability. These cases aim to mitigate the environmental impact associated with traditional wood waste treatment processes and provide a pathway to carbon-neutral production:
• Case 1: The traditional wood waste treatment process involving full syngas combustion, while providing a solution for biochar production, falls short in terms of sustainability due to high emissions and limited carbon credit potential.
• Case 2: With partial syngas combustion, this case offers a balanced approach, reducing emissions and improving energy efficiency while still producing valuable syngas for biofuel and chemical production.
• Case 3: Utilizing hot inert gases powered by renewable energy, this case presents the most sustainable approach by minimizing emissions and enhancing energy efficiency.
In the conventional approach to wood waste treatment, Case 1—drying, pyrolysis and post-combustion of syngas—presents several challenges in terms of carbon credit generation. While biochar production through pyrolysis offers potential for carbon sequestration, the emissions produced during the syngas combustion phase significantly undermine the environmental benefits of the process.
This phase releases high levels of CO2 and NOX, contributing to greenhouse gas emissions rather than mitigating them. As a result, Case 1 does not fully align with the principles of carbon neutrality or carbon credit generation. The high emissions produced during the post-combustion phase disqualify this method from being eligible for meaningful carbon credit generation, which is an essential mechanism for promoting sustainable practices in the fight against climate change. Carbon credits are typically awarded for processes that lead to significant emission reductions and carbon sequestration.
Adopting Cases 2 and 3 for biochar production, especially with syngas reforming, is a highly promising approach for achieving higher carbon credits and contributing to climate change mitigation, for the following reasons:
• Case 2 (with controlled syngas combustion) allows for lower emissions of CO2 and NOX, generating heat and syngas that can be used to produce biofuels and chemicals. This dual benefit of energy recovery and reduced emissions makes it a practical intermediate solution.
• Case 3 (with no combustion and using hot inert gases from renewable sources such as solar or wind energy) represents a zero-emission process with no CO2 or NOX released. This makes it the most sustainable option for biochar production. Additionally, integrating syngas reforming for biofuel and chemical production adds further value by generating renewable energy products without the environmental impact of traditional fossil fuel-based processes.
Both of the above cases align with the principles of a circular economy and sustainable energy systems. However, it is crucial to consider the CO2 production associated with not only the primary thermochemical and chemical processes involved in converting, reforming and recycling WtX, but also with the upstream production of the necessary chemicals and materials used in these processes. The overall carbon credit potential of a WtX solution must account for these indirect emissions to ensure that the entire process achieves genuine and significant carbon credit generation.
Author: Ahmad Saylam Researcher, Developer and Lecturer
Applied Physical and Chemical Sciences +49 157 72076595
FEEDSTOCK VARIABILITY: DIFFERENCES AMONG BIOMASS ANATOMICAL FRACTIONS AND TISSUES
Researchers from the U.S. DOE’s Feedstock-Conversion Interface Consortium describe sources of feedstock variability and why it matters for biorefinery operations.
BY DONOHOE, YINING ZENG, XIHUI KANG AND NING SUN
Corn stover is a versatile feedstock for producing biofuels and other sustainable products. However, its diverse chemical and physical attributes can hinder the processes that convert it into these compounds. The composition of corn stover varies according to factors including corn plant variety, cultivation conditions and maturity at harvest.
In essence, corn stover consists of the polymers cellulose, hemicellulose and lignin. The structural core of plant cell walls consists of elongated chains of glucose molecules arranged in bundles of cellulose. Additionally, lower concentrations of hemicellulose, a complex carbohydrate composed of various sugars, form part of the matrix surrounding cellulose bundles. Lignin is a complex aromatic polymer that reinforces plant cell walls. Corn stover generally comprises 40%-50%
cellulose, 20%-30% hemicellulose, and 20%30% lignin. The ratios of these components vary based on the specific type of corn plant and the growth conditions. For example, corn plants cultivated in drought conditions exhibit higher lignin levels than those grown under optimal conditions. The compositional diversity resulting from growth conditions is most pronounced among the different anatomical fractions of the corn plant. Understanding and accommodating the variation among the anatomical fractions of corn stover can enhance the effective utilization of this resource.
Realizing and Addressing Anatomical Fraction Variations
What are the major anatomical fractions of corn plants that comprise corn stover? Corn stover refers to the residual biomass of the corn plant following grain harvest, com-
prising the stalks, leaves, husks and cobs. Each fraction has distinct attributes stemming from its role in living plants (Figure 1).
Corn stalks are the corn plant’s vertical, fibrous structures that support the leaves and ears. Corn stalks are stout and rigid. Their diameter varies based on the corn variety, growth conditions and age. Stalks are the dominant fraction by mass, comprise the majority of the structural carbohydrates, and are a primary target for biofuel and product feedstock utilization. The stalk consists of three primary tissue layers arranged from outside to inside: the epidermis, rind and pith. The epidermis constitutes the outermost layer of the plant’s surface, comprised of a thin layer of cells. The primary function of the epidermis is safeguarding the plant against physical damage, preventing water loss and inhibiting infection. The epidermis also plays a role in
CONTRIBUTION: The claims and statements made in this article belong exclusively to the author(s) and do not necessarily reflect the views of Biomass Magazine or its advertisers. All questions pertaining to this article should be directed to the author(s).
regulating gas exchange. The composition includes distinctive waxy polymer components that are only a minor fraction of the plant’s overall mass. The rind is the tissue layer beneath the epidermis, consisting of cortex and vascular tissues. Fiber cells within the cortical tissue play a role in starch storage and offer mechanical support. The vascular tissue includes the xylem and phloem vessels, which are responsible for transporting water, nutrients and sugars within the plant. The xylem is also responsible for transporting water and dissolved minerals from the roots to other parts of the plant. In contrast, the phloem facilitates the distribution of sugars generated through photosynthesis throughout the plant. The pith is a soft, low-density tissue located at the center of the stem, characterized by thin-walled cells that contain minimal lignin. It does contain lignified vascular tissue; however, the pith is normally straightforward to deconstruct and convert.
Corn leaves exhibit a thin and flexible morphology. Leaves are connected to the plant’s stalk at a node via a stemlike structure known as a petiole. Like the stalk, corn leaves possess an epidermis, but the leaf’s interior contains mesophyll layers. The epidermis on the outer surface of leaves protects them against physical injury and dehydration while managing gas exchange. Mesophyll tissue consists of thin-walled cells with interstitial
spaces. Mesophyll is essential in photosynthesis, providing an extensive surface area for sunlight absorption and gas exchange.
Husks are the protective outer layers of the corn cob that safeguard the seeds. Their structure and composition are nearly identical to those of the leaves. Consequently, husks exhibit a degree of flexibility that facilitates their removal from the corn cob.
Cobs are the central structures of the corn plant that contain the seeds. Corn cobs are relatively rigid and do not possess the elongated vascular tissue found in other anatomical components. This characteristic allows easier milling into smaller, more uniform particles, which facilitates conversion.
The various tissue types in a corn plant collaborate to facilitate the plant’s growth and development. The variability in physical properties among the anatomical fractions is evident throughout the corn plant and persists from harvest through the entire biorefinery process.
What challenges does feedstock variability pose for the integrated biorefinery? Biorefineries utilize renewable feedstocks such as corn stover and various agricultural waste to produce biofuels and bioproducts. Nonetheless, the variability in feedstock attributes presents challenges for biorefineries, as it can significantly affect the efficiency and yield of the processes that convert these feedstocks into
valuable products. The variability in chemical composition, which can differ markedly among plant species, has historically garnered considerable focus. Nonetheless, fluctuations in physical characteristics, including particle size, moisture content and density, influence the flowability and handling of feedstocks, as well as the operational efficiency of the processing equipment. For example, in high-temperature conversion of feedstocks, jamming of the screw feeder is a challenge for smooth operation. We find that when pine fractions are delivered to pyrolysis reactors via feed screws, the indirect heating induces different changes among the anatomic fractions. The surface texture of all anatomic fractions changes at elevated temperatures. Cambium and whitewood fractions show more reduction of size at 250 degrees Celsius and above. Cambium and whitewood produce more resin acids, and more bio-oil droplets are observed on bark and cambium particles.
The conditions under which crops are grown, the techniques used for harvesting, and the methods of storage are among the factors contributing to feedstock variability that our consortium has investigated. While each of these factors may influence the quantity and quality of biomass feedstock that ultimately arrives at the biorefinery, the inherent variability in the anatomy of feedstock plants remains the sole source of variability that is
consistently observable, independent of the upstream processes. This persistent source of variation is generally more substantial than growth, harvest or storage.
Biorefineries can adopt various approaches to mitigate the impacts of feedstock variability. These include preprocessing feedstocks to enhance their uniformity, blending different feedstocks to even out compositional discrepancies, and establishing quality control protocols to ensure a steady standard of feedstock quality.
Which fractions of corn stover are the easiest and hardest to convert into biofuels? Several factors can influence the ease of converting varying amounts of corn stover into biofuels, such as the type of conversion process employed, the properties of the feedstock, and the specifications of the intended end product.
The leaves and stalks represent the predominant portions of the plant, exhibiting a greater structural carbohydrate content than the cobs and husks. Consequently, they are often regarded as the most sought-after element of corn stover for conversion purposes. The presence of lignin, however, is known for its resistance to degradation and may complicate the processing of these components. Conversely, the husks and cobs possess a lower concentration of structural carbohydrates, but they are easier to process due to their lower lignin content and a more open, porous structure, which enhances access to the cellulose and hemicellulose polymers. The ease of collection alongside the grain suggests that cobs could facilitate more efficient harvesting and transportation processes.
The desired final product, the feedstock’s cost and availability, and the operation’s scale will dictate the optimal feedstock and conversion technique. Therefore, experts in the field are persistently innovating technologies and methodologies to convert corn stover and other biomass feedstocks into cost-effective biofuels.
Systems to Mitigate Variability Challenges
The variability of the physical attributes of anatomical fractions is more significant than that of their chemical counterparts, making thorough and efficient preprocessing one
of the most critical mitigation techniques. Standardizing the biomass into a consistent particle size and shape addresses numerous flowability and handling challenges, and also standardizes the accessibility of biomass for pretreatment and conversion catalysts
Blending represents a viable approach to addressing the challenges posed by the variability of corn stover. Blending can improve product quality and processing efficiency by producing a more uniform feedstock, particularly in terms of composition. For example, higher levels of lignin in specific anatomical fractions could adversely affect the quality of the final product. The dilution of high lignin content through blending enhances the overall quality of the final product.
Another promising approach to address the challenges of diverse anatomical fractions of corn stover is through fractionation. Fractionation enhances processing efficiency by dividing the biomass feedstock into fractions that exhibit more uniform properties that are easier to manage, and then utilizing specialized equipment tailored to each fraction. More-
over, fractionation can potentially improve the final product’s quality by isolating specific components of corn stover. For example, the leaves, abundant in cellulose, could be processed independently to yield high-quality fermentable sugars. The lignin-rich stalks can be processed separately in a lignin-first processing scheme to produce aromatic products. Air classification is an efficient method utilizing high-speed airflow to effectively separate lighter materials, such as leaves and husks, from heavier components like stalks and cobs, achieving this at a low cost and with high capacity. As a result, the feedstock composition could exhibit greater consistency, leading to an enhancement in product quality. Furthermore, fractionation removes contaminants like dirt and rocks from the feedstock, reducing the risk of damage to processing-related equipment.
Should different parts of the corn stover plant be used for different purposes? Various parts of the corn stover plant can be employed for distinct conversions based on their chemical and physical properties. Corn sto-
Figure 1: Images and illustrations of the major fractions of corn stover. Both at the macroscale and microscale, tissue and cellular architecture vary among the anatomical fractions.
IMAGE: NREL FCIC
ver’s leaves and stalks often contain high levels of cellulose and hemicellulose, which can be transformed into sugars and fermented to generate biofuels or various chemicals. Conversely, the cobs and husks typically have lower levels of cellulose and hemicellulose while exhibiting higher lignin content. This composition may render them less ideal for biofuel production, yet they could be more advantageous for alternative applications such as animal feed or soil enhancements.
Different components of the corn stover plant may possess differing levels of minerals such as nitrogen, phosphorus and potassium, rendering certain parts more appropriate for fertilizer or soil amendments in agricultural practices. For example, although the cobs and husks of corn stover can add organic matter to the soil, the leaves and stalks might be more beneficial for improving soil fertility.
In summary, a range of factors including the chemical and physical properties, the intended final product, and the regional supply and demand for different biomass feedstocks will influence the optimal utilization of the corn stover plant’s various components. Thus, it is essential to thoughtfully evaluate these factors and innovate technologies and practices that enhance value while reducing the environmental impacts associated with corn stover and other biomass resources for their practical and sustainable utilization.
The challenges of anatomical fraction variability seen in corn stover extend to other bioenergy crops, such as switchgrass, miscanthus, sorghum, pine, poplar and wil low, due to the intrinsic heterogeneity of plant components. For instance, like corn stover, these crops have distinct anatomical parts—leaves, stems, and sometimes woody cores—that vary in chemical composition. Switchgrass and miscanthus exhibit the same differences in cellulose, hemicellulose and lig nin concentrations between leaves and stems, similarly impacting their suitability for biofuel production or other bioproducts. This vari ability complicates the uniform processing of biomass since each fraction may require dif ferent pretreatment methods or conversion pathways to maximize efficiency.
In woody bioenergy crops like pine, poplar and willow, anatomical variability is further pronounced between bark, sapwood
and heartwood. Bark often contains higher amounts of lignin and extractives, which can hinder enzymatic hydrolysis and fermentation processes. At the same time, sapwood is typically richer in cellulose and hemicellulose, making it more suitable for biofuel production. However, separating these fractions during harvesting or preprocessing adds logistical complexity and costs. Additionally, the anatomical heterogeneity of these woody crops poses challenges for thermochemical processes like pyrolysis or gasification, as varying lignin content can affect yield and product quality.
Sorghum, a highly versatile bioenergy crop, demonstrates significant variability between its stalks, leaves and grains. The stalks are rich in fermentable sugars and suitable for fuel production, while the leaves contain less sugar and more lignin, making them better suited for combustion or soil amendments. Across all these crops, addressing anatomical fraction variability necessitates advancements
in selective harvesting, fractionation technologies and process optimization to enhance overall biomass utilization while minimizing costs and environmental impacts.
In summary, our extensive work looking at the causes and extents of feedstock variability has revealed that the differences among biomass anatomical fractions and tissues remain at the core of feedstock variability. Even where growth conditions, harvest and storage have impacted feedstock quality, the variability among the anatomical fractions persists and normally exceeds the variability induced by other factors.
References available upon request.
Authors: Bryon S. Donohoe, Yining Zeng, Xihui Kang and Ning Sun
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