Yield Quest for Cellulosic biofuels

November 13, 2014 |

ABLC2014N2-lgCould a new wave of cellulsoic processes find the key to capturing the carbon lost by today’s technologies — and providing a drive to lower costs that busts through infrastructure barriers?

Iogen has been running its cellulosic ethanol pilot continuously since 2004, which makes CEO Brian Foody one of the go-to people on the realities of making cellulosic biofuels, and making them competitive with incumbent gasoline.

His take — as expressed in his presentation this week at ABLC Next, in San Francisco?  Short-term, the barriers to cellulosic adoption relate back to of the cost infrastructure change – rather than the cost or performance of the fuels themselves today.

Long-term? The solutions, he suggests, lie in the development of a new generation of processing technologies that would ultimately address limitations inherent in the technology today — limitations that related back to carbon yields and the efficiencies of today’s technology.

Let’s investigate.

1. The First Wave hits the beach

Good news, a lot of technologies are arriving at scale right now. Ten have been scaled up, Foody observes (including two failures) — and two more on the way with major corporate sponsors.

In the case of Iogen, the company is commissioning its 10 million gallon Raizen facility in Brazil right now, at a capital cost of around $100 million and using sugarcane bagasse as a feedstock. Raizen has announced that, once this one is operational, it will build seven more cellulosic plants.



1. Job #1, operating reliably at scale

Foody observes that, as monumental a task as designing a process, raising capital, sourcing feedstock, and constructing and commissioning a plant will be — the toughest ongoing task is to ensure reliable operations.

Resolving erosion problems and eliminating line plugging are just two of these “devil in the details” issues.iogen-4


3. The strategic view — Can cellulosic ethanol compete ultimately successfully with incumbent fuels on cost, not just on greenhouse gas emissions?

Yes, says Foody, pointing to the story of first-generation ethanol, noting that the evidence points to a wide gap between conventional ethanol and gasoline costs that was narrowed year by year, and has now been eliminated. In fact, on an energy basis, ethanol is generally in the US cost-effective compared to gasoline many months out of the year.


4. The Cellulosic Challenge

It’s not in RIN credits and cellulosic waiver credits in the long term, says Foody. The answer lies in driving better yields and better economics.

While $1.50 per gallon opex and $6-$10/ gallon capex is huge progress, he says, ultimately the wall that threatens cellulose biofuels adoption is as much a technology wall as a blend wall. In this case, he points to 75-95 gallon yields of ethanol per ton of biomass.


5. Shift more feedstock to fuel

Let’s talk carbon, says Foody. Is there carbon left behind by today’s processes? Carbon that could be the basis of more fuel, at lower prices?

Interesting question. You see, there’s around 800 pounds of carbon in a ton of corn stover — and, with ethanol consisting of roughly 52% carbon (the rest is oxygen and hydrogen) there’s as much as around 1530 pounds of fuel, potentially, in a ton of biomass — around 250 gallons per ton.

So, why do processes only yield 75-95? Carbon is being left behind in the form of lignin, and being taken out in the form of C02, which is fermentations way of taking out the oxygen, a necessary step in converting a sugar to a fuel.

No matter what, Foody says, in the long term cellulosic fuels will have to deal with the issue of E10 saturation — by being cheap enough that they incentivize adoption of higher ethanol blends, or by finding new processes to produce drop-in fuels.


He’s hopeful, pointing to data that suggests that the RFS RIN mechanism provides precisely the kind of price signal that can drive adoption of higher ethanol blends.


5. Another option – renewable hydrogen?

Another opportunity awaits as a means of  shifting more feedstock to fuel, says Foody, In raising the option of renewable hydrogen, seen below in this slide presented at ABLC Next.  Doing so in a way that can bolt-on to existing infrstructure, produce infrastructure compatible fuels using existing equipment and infrastructure.


6. The Bottom line

Does Iogen have the answer for the next generation of cellulosic fuels. We’ll see – they have continued to prove out a winner in second-ten, so we’re not discounting their chances by one penny here in Digestville.

Regardless of the path, though, they certainly have identified the challenge. Find ways to capture that carbon, rather than losing it through today’s processes — and that may well be the path to driving down costs, that in turn drive cellulosic fuels through the blend wall.

Perhaps, in that way of thinking, the very unfortunate barrier that infrastructure places in the way of adopting low-carbon fuels — in this case, the E10 saturation barrier — may well be the very spur for new technology that makes that barrier a thing of the past through market forces.





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