17 answers for your burning questions about biofuels, renewable chemicals, biomass and more.

At ABLC and other conferences this year, you’ve been asking, and the experts have been answering. Here are 17 of the most popular questions that get asked. 

Q. We’ve heard a lot about carbon capture, but what about carbon capture and conversion (to a more soluble, transportable and storable form), for example conversion to bicarbonate?

A. To date, all ventures in the carbon capture and use field have contemplated co-location with a point carbon source. To some extent, logistics dictate this, since a conversion site has to be built anyway, power plants and ethanol plants have substantial infrastructure to support fuels and materials production (e.g. rail, water, and power). Plus, there’s so much carbon, typically, at a point source that there’s little need to contemplate a hub-and-spoke production system. Some ethanol plants have installed CO2 liquefaction plants and that route is one where the carbon will be shipped off-site.

Q. What is done with sweet sorghum residue after squeezing?

A. Residual biomass can be used in cellulosic applications, not unlike bagasse or corn stover, combusted for power, or returned to the field as a soil amendment. Typically to date, we’ve seen the latter.

Q. How do you control sugar degradation during storage?

A. Ultimately, airborne microbes abound and sugar will start to ferment if left alone long enough. Controls include keeping biomass as dry as possible, and cold. In the case of liquid sugars, sterile storage is one key, temperature is another. Ultimately, just-in-time production is the best answer.

Q. Can processes really use blended feedstocks — or is the talk of being feedstock agnostic just talk?

A. Leaving aside gasification, talk of “feedstock agnosticism” is generally just talk. Processes generally prefer feedstocks that are easy to reduce to consistent (and small) sizes), and can be consistently pumped with a minimum of water content. The more water, the tougher on the process, the less water, the tougher on the piping. Less acidic feedstocks also generally perform better on equipment, too. At the end of the day, it’s probably true that processes can handle a wide variety of feedstocks, but the equipment that is eventually installed to run the process is less agnostic. In any case, companies rarely have the lab resources or the site choices to contemplate more than a handful of feedstocks.

Q. We have heard that there are 106M acres of sorghum planted globally. How many acres of switchgrass? How can we track the growth of energy crops?

A. AgMRC has a good report on the state of switchgrass development, here, though it needs updating.

Q. Is there any correlation between biomass yield and lignin content in poplar?

A. Appears so, according to research in Belgium,. focused on the suppression of the CCR enzyme. More about that here.

Q. How is “marginal land” defined?

A. Marginal land is land that is currently out of production, or cannot provide a acceptable minimum return per acre to justify production without subsidies, based on existing crops and technologies. What makes it marginal, compared to desert for example, is that with new crops and technologies the production value per acre could be raised to acceptable returns.

Q: Could technologies like Modern Meadow that culture animal cells to make, for example, meats and leathers, also employ plant cells and produce products that have both?

A. Plant tissue culture is used extensively in micropropagation — for example, to produce plant clones. So, there’s that. AT this stage, no one is following that line of applied research that we know. However, as a general statement, its been shown in basic research that cells can be cultivated together, and even hybridized in some cases.

Q, What technologies are likely to develop faster over the next 10 years?

A. Generally, those technologies that get their research well-funded! As a blanket statement, bet on biology. So, feedstock yields will improve faster than process yields and separation technology.

Q. BASF has been touting its enhanced oilfield recovery technology. Why is it better than other techs out there?

A. These are the Aspiro polymers. Here’s what BASF says:

The Aspiro P4 series are partially hydrolyzed polyacrylamides of varying molecular weight and/or degree of anionicity. They provide a cost efficient solution for mild field conditions. Incorporation of stabilizers extends the application window of such polymers to up to 85°C. The Aspiro P5 series are sulfonated polyacrylamides. They allow for use at harsher conditions up to 95°C. Aspiro P6 associative thickening polyacrylamides are the next generation technology designed to provide tolerance to extreme salinity and hardness while also producing higher mobility control with lower dosage than standard polymers.

Q. We don’t hear as much as before about forest biomass for feedstocks, usually we hear about agricultural residue.

A. Generally, that’s because the applications that have come along first have been enzymatic hydrolysis tech that likes crop residues, and the grower relations have already been in place. Companies like UPM are just now coming forward with their chosen solutions with partners like Renmatix. Forest biomass will be a big story in the second half of the decade.

Q. What about government help for renewable chemicals, not just fuels. For example, opening up Section 9003 grants for chemicals?

A. Integrated biorefineries can get help under Section 9003 of the Farm Bill, and they can produce chemicals or fuels. Ultimately, it’s an artificial distinction based on use; obviously, all fuels are chemicals, though typically they are blends. Good news for renchem fans though: Senators Stabenow (D-MI), Coons (D-DE) and Franken (D-MN) introduced S. 2271, the Renewable Chemicals Act of 2015, a bill to amend the Internal Revenue Code of 1986 to provide credits for the production of renewable chemicals and investments in renewable chemical production facilities.

Q. How do we measure CO2 escaping from open ponds. Who is responsible for it?

A. In this question, we look at CO2 that’s been brought in from a point source, bubbled in a pond, yet not grabbed by an algae cell as an energy source. Ultimately, it counts as “carbon not captured”, and would be attributed to the original emitter unless local regulations dictate otherwise. It’s a percentage calculation, a yield loss, if you will, and all processes have them.

Q. How does corn ethanol in its E15 or E85 versions address the implications of food price increase or reduce carbon emission?

A. On the whole, food price variations do not correlate to underlying food ingredient commodity price changes, especially where we are looking at modern food where transport, retail, brokerage, and finance dominate the final cost of the product. For example, corn prices have dropped substantially and steadily since 2012, and fuel prices have been in free-fall since 2014, but there’s been no corresponding decrease in food prices.  With respect to emissions, depending on your choice of consensus-based research, corn ethanol, reduces greenhouse gas emissions between 21 and 34 percent, compared to baseline 2005 gasoline. More ethanol, less greenhouse gas reduction.

Q. How have water concerns in California influence or impacted the potential to add renewable fuel production in California? Are investors spooked, with Canergy as an example?

A. Investors are spooked far more by policy instability and market risk than water risk, but drought is never a positive. As a general rule, we’re going to see a lot more fuels targeting California but produced elsewhere, as opposed to “produced in California”, in terms of meeting increased demand. Having said that, residues are widely available — food waste, ag waste, municipal waste, and these can be used without stressing the water supply.

Q. In the case of burning tobacco residues after bioprocessing, is there a concern of cancer caused by nicotine?

A. No, air permit regulations are in place everywhere and hazardous emissions will be remediated at the point of emission, as required by local authorities. Having said that, there’s always the possibility that a transformative business model may emerge in the hemp biofuels market where you give away the fuel and sell the smoke. (Just kidding, you don’t actually use psychoactive feedstocks for hemp biofuels.)

Q. Why would farmers grow cellulosic crops with only a few cellulosic plants in operation and with markets too far away to haul biomass?

A. Unless protected by grants and subsidies aimed at solving chicken-and-egg problems in getting biomass grown to support a greenfield plant under development, farmers won’t grow biomass where it is too costly to haul to market. For the same reason that farmers didn’t expand into the prairies until the railroads arrived. Yet, there are lower-value uses for cellulosic feedstock (e.g. biomass power) that may justify some growing before high-value integrated biorefineries appear. In the history we’ve seen in the farm sector, the biomass appears first, hauled to a distinct market, and then the local plant emerges to raise returns to farmers by cutting transport costs. In the case of $20-$50 per ton biomass, that’s not going to be all that far, as transport costs will mount. Think around 3 cents per ton per mile for railing biomass, and you get the idea quickly that while 100 miles doesn’t present a problem, 1000 miles really changes the economics.