I was reading this month’s Scientific American last night and came upon an article on ethanol. You can’t read it without a subscription, so, sorry about that. Matthew Wald, a reporter for the New York Times, wrote it. Interestingly enough, not everyone at the NYT appears to have the same opinion on corn ethanol.
I was expecting the usual: inaccurate, incomplete, and pseudo-neutral. However, it turned out to be quite good. The article was long (which is a necessity with complicated topics), and the author made no pretense of neutrality.
Instead of charts or curves it used three-dimensional, life-like renderings that a kindergartener could understand to compare cellulosic and corn ethanol biorefineries — which is why I learned a bunch from it. I thought I was nearing the top of the learning curve on this issue. For example, some research on cellulosic is using the microbes found in the guts of termites. Being symbiotic lifeforms that have co-evolved in the stomachs of termites for hundreds of millions of years, they are understandably having a hard time adjusting to giant stainless steel tanks. Other researchers are using a fungus found in jungle leaf litter. Jungles are full of undiscovered things. Too bad they will one day be converted into palm oil or sugarcane plantations.
The two refineries (corn and cellulosic) did not share the same equipment until about two thirds of the way along the process.
- Corn showed up at the refinery in railroad grain cars. Cellulose somehow arrived in huge bulky bails (how they got these bails there was not discussed or illustrated, which is just one of the issues yet to be dealt with).
- Next, the corn went to giant industrial-sized grinders powered by electricity to expose the starch. The cellulose went to a giant vegetable steamer powered by whatever to soften it up for the next process.
- The corn then moves on to a slurry tank, a jet cooker, and finally to a tank called a masher that extracts starch and sugar from it. The cellulose skips all that and goes straight to tank called a bioreactor, where enzymes break the cellulose down into starch or sugar.
- At this point you have sugar. From here on, the process for corn and cellulose is the same and can use the same equipment. The sugar is fed to microbes in a fermenter. Their metabolic waste product (they pee ethanol) is distilled out and shipped off in tanker trucks.
As you can see, switching these refineries over to cellulosic won’t be cheap or easy. The argument that you must sit down, shut up, and pump ethanol if you ever want to see anything better is starting to sound like extortion. Corn ethanol is not blazing a path for cellulosic. Congress just last week voted to continue the subsidies and this is probably going to go on for several more decades. The author did an incredible job of ripping corn ethanol on several fronts that should be familiar to anyone following this technology and came to pretty much the same conclusion I have:
“Backers defend corn ethanol as a bridge technology to cellulose ethanol, but for the moment it is a bridge to nowhere.”