Fermentable cellulosic sugars for capex of 6.5 cents per gallon? Freakishly low-cost venture still at early-stage.
It’s a capex figure so low that it sounds like a decimal point is missing.
Though early-stage and just developing data out of its pilot — it’s well worth seeing what Sustainable Ethanol Technologies is up to, in its aim to drive down the capital costs of extracting cellulosic sugars from biomass.
Among the many technologies that work on the front end of cellulosic biofuels — that is, extracting fermentable sugars from a targeted non-food biomass, we hadn’t ever heard of a system that cost $65K per million gallons in capex, and 60 cents per gallon (excluding the cost of biomass) in the opex, until we ran into Sustainable Ethanol Technologies — very early-stage and just now emerging out of stealth-mode in North Carolina.
Systems usually run into the millions, even at small-scale, for the front end saccharification — that biomass just doesn’t want to give up its sugars, it’s worse than prizing a winning lottery ticket out of someone’s hand. So, it’s costly.
“Our advantage is low cost,” says CEO Julie Goodliffe, whose startup out of UNC Charlotte received the first strategic corporate partnership award from the Charlotte Venture Challenge for their patent-pending process to produce cellulosic ethanol from any kind of biomass.
“Nature has solved the problem of breakdown, our fungi grow through the biomass, and the fungi can degrade the lignin and then get to the sugars.”
How does it work? “We allow our fungi to grow on biomass, then breakdown the living system in a pile of woodchips or stover. We allow them to do it for 45 days, then mechanically grind. No acids or enzymes.”
Why so low-cost? “We don’t need a stainless steel tank, a concrete slab will do,” Goodliffe added. ” We don’t need lots of water, nor do we have hazardous chemicals in the process.”
SET’s pilot-scale facility.
How does this compete or pair up with existing technologies that extract sugars? “The cellulosic ethanol industry and others like Sweetwater are reducing costs but still need improvement. Their process is complimentary, they can use our fungi, our biomass, and it doesn’t doesn’t interfere downstream.
Where is the company in terms of scale-up? “The research has been done at lab scale,” Goodliffe told the Digest, “and we’ve shown that our fungi will grow on different types of biomass; we’ve studied sugars in woodchips, pine, corn stover. We have been getting enough to ferment the sugars. And, we haven’t been using autoclaves or other systems that wouldn’t be used in the field. We’ve used barrels, very dirty, with biomass from MSW at the EcoComplex and tipped yard waste. We innoculated it with fungi, left it, then grind it via a hammer mill, and tipped into a fermentation tank, then distilled it and got ethanol.
The yields? “We can convert 14% of woody biomass into sugars,” Goodliffe said. So, that translates into something like 40 gallons per ton, which is low. “we’ll need more time and funding to optimize the process, and validate at scale.”
The business model? Goodliffe explained: “The model is licensing the technology; we’ll need third parties to test, such as an ethanol producer or lab.”
Why 45 days? “At this stage, its optimal in terms of maximizing sugars and having very little loss, if any, of the biomass itself,” the CEO continued, “The fungi are going to eat a little bit, so we use whiterot fungi to eat through lignin, that’s 30 days. Then we use then the brown rot for 15 days to get through to the sugars. We stop there because otherwise they will eat the sugar.”
Are there economies of scale in that $65K cost per million gallons process? “They are there, but we’re going to need engineering resources to study that.”
The Digest’s Bottom Line
An ingenious concept, very early-stage. Complimentary to other processes that use harsher, faster measures at larger scale. But well suited to the concept of extracting the sugars locally, right on the farm — think about transporting 280 pounds of sugars instead of a ton of biomass, from either on-farm operations, or local sugar extraction locations.
How much can the process be optimized, what mixes of sugars (e.g. C5, C6) can be obtained, hoe are adverse weather conditions tolerated, how much water in the biomass can be tolerated — these are questions that need to be answered. But any system that can produce sugars with these kind of upfront costs — 6.5 cents per gallon — is going to attract attention and investigation.
One is of the pilot plant (one 500-gallon fermentation tank, one 600-gallon distillation tank, one condensation tank attached to the distillation tank, and the hammermill in the foreground), and one is of wood chips with our fungi growing on them (white on the wood chips).
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