Sweetwater receives final acceptance of commercial Sunburst unit at Sweetwoods Project in Estonia

While all eyes have been on Ukraine lately, there is some good news that came in from another former USSR republic and neighbor to Ukraine’s north above Belarus and Latvia – Estonia – a NATO country that borders Russia. U.S. based Sweetwater Energy received final acceptance of its first commercial Sunburst unit at the Sweetwoods Project in Estonia, proving that Sunburst has met all criteria—including energy usage, throughput, and quality of product.

In today’s Digest, the Digest exclusive interview with Arunas Chesonis, Sweetwater’s CEO, details on the lead company in the Sweetwoods consortium, Estonia-based Fibenol, plans for the future, and more.

The Backstory

Let’s start with a bit of background on the Sweetwoods project. It is a Bio-Based Industries Joint Undertaking (BBI JU)-funded venture that uses sustainable hardwood to demonstrate how Sunburst’s breakthrough pretreatment technology, in combination with tailored enzymatic solutions, can provide high-quality lignin and wood sugars at an industrial scale.

Sweetwater Energy uses a unique technology for producing low-cost nanofibrillated cellulose, microcrystalline cellulose, cellulosic sugars, and clean lignin from non-food plant materials to help meet the modern world’s increasing bioenergy and biochemical demands. The company began in 2009 as a spinout from the Rochester Institute of Technology with funding from the New York State Energy Research and Development Authority, and is now in the beginning stages of planning its first commercial facility.

Fibenol is developing this first of a kind wood fractionation plant in Estonia with ambition to transform wood bioprocessing industry to more efficient and cleaner industry. Concept allows woody biomass to reach significantly wider end-use applications than conventional biorefineries do and use more than 90% of the wood fiber in the raw material to be converted into high value products. Final commissioning and ramp up to design capacity of the plant is targeted into mid-2023.

The Project

Fibenol needed a technology that could efficiently process different wood species into high- purity cellulosic sugars and lignin, while having a minimal physical and ecological footprint.  The Sunburst pretreatment module requires less than 250 square meters to convert wood flakes into easily pumpable homogenous liquified wood slurry.

On top of that, the Sunburst pretreatment system has proven itself incredibly reliable, reaching full commissioning in fewer than 30 runs and taking less than 45 minutes from startup of the system to reach in-spec conditions. Its output products are highly pure and largely free of unwanted byproducts, making the industry’s dream of a true biomass biorefinery possible.

The high quality of Sunburst’s sugar has already translated into top fermentation performances for the production of bio-isobutene—a key ingredient to replace fossil-based products in the energy, materials and cosmetics markets. Global Bioenergies’ Director for Industrial Strategy Bernard Chaud says, “As a partner in the Sweetwoods Consortium we tested the new Sunburst’s cellulosic sugars at pilot scale and found that they allow for the high productivity of bio-isobutene with similar performances compared to traditional sugars. The consortium has already initiated demo-scale bio-isobutene production, and conversion of this bio-isobutene into renewable aviation gasoline was successfully demonstrated.”

“We searched for years for a technology that would meet all our criteria to transform the wood processing industry into a biomaterials and biochemicals industry,” says Peep Pitk, Chief Development Officer of Fibenol OÜ, the lead company in the Sweetwoods consortium. “We are very pleased to announce that Sweetwater’s Sunburst pretreatment has reached agreed performance targets, and has exceeded expectations on steam use, throughput, ease of implementation, and operations. Sunburst has now achieved the Sweetwoods consortium’s goals in a compact, elegant design that converts more than 90 percent of the biomass into useful products.”

When asked about timing in an exclusive Digest interview, Arunas Chesonis, Sweetwater CEO said, “Operations is not the issue, it’s really a matter of tapping the demand and finding those pioneer customers who have that need for specialty cellulose. Now, we have that ability with Fiberol running to do the large samples for those customers who need them for testing, because that plant can now run 80 tons per day.”

As for the value proposition, Chesonis told The Digest, “It’s a commercial, modular system, as we had always aimed to deliver to industry.”

It takes a team

None of this could have been possible without the dedication of the team at Sweetwater and their counterparts at Fibenol OÜ in Estonia. As Samjitsingh said, “Working through the pandemic on this first-of-its-kind technology was demanding, but always enjoyable because of the camaraderie and alignment of the Sweetwater and Fibenol teams. It was very fulfilling for all involved.”

“Commissioning of Sunburst started within two years of signing the agreement for the Sunburst equipment, even despite the pandemic—a testament to the ease of implementation of the technology,” said Chesonis. “Our team, led by Director of Commercialization Sharon Samjitsingh, definitively proved that Sunburst excels at commercial scale. We are excited for how this will enable the production of sustainable fuels and materials while helping to mitigate climate change.”

And Chesonis told The Digest, “We’re already talking to partners who can take all streams, and partners more interested in one stream over another.”

Bottom Line

In a week full of bad news from this part of the world, it’s a bright light in the dark and a bit of hope for the future which looks sweet for Sweetwater and Estonia. “The next milestone step would be to move to 24/7 operations,” said Chesonis. “Also, we just received our key patent in the US. For a couple of years, we’ve had the provisional, but not that’s final.”  That’s also good news for Sweetwater’s MOU and project with Gevo as reported in The Digest in November 2021.  We hope to hear more sweet news from Sweetwater and their projects, including the Sweetwoods Estonia-based project.