Friday, February 8, 2008

Membranes to Replace Distillation

Distillation is by far the most energy intensive step in the production of ethanol and it consumes large amounts of coal or natural gas (depending on the plant), which comes at a high cost to the company. A group of researchers in the Netherlands has developed a membrane that can separate the water out of ethanol; bypassing a lot of the energy needed for distillation and potentially being a great step forward both for ethanol economics but also for the energy balance/GHG emissions that people have pointed out so vocally in the press. Although the idea of developing a selective membrane to filter the water out of ethanol is not new, (a group in Canada has also done this, among others), tests on these membranes has shown that their effectiveness can not climb about 40% pure anhydrous ethanol.

Although the Dutch group was able to develop a stable membrane capable of separating large amount of ethanol from water, the procedure requires temperatures above 150C. This plus the fact that the membrane is unstable below 60C and their claims that the process is energy efficient seems hard to prove. Keep in mind that the boiling point of ethanol is 78C, which is the temperature currently needed for distillation. Although using current technology this still only results in approximately 96% ethanol and necessitates an additional step in anhydrous ethanol is needed, the Dutch team claims to be able to displace some of the energy needed for distillation, which I can not verify and have some large doubts. Either way, a cool technology with big potential but it may be a few more years off before the engineers can get a better handle on it.

A computer generated image of these nano-sieves.

Original publication:

Thursday, February 7, 2008

Biofuel's GHG emissions

Although there could be a very large post refuting each claim point-by-point, I'm going to start with this one and make it brief and to the point. I thought we had moved away from the days of irresponsible scientific work by Pimentel, (the only researcher to declare that corn-based ethanol has a negative energy balance back in 2005), but from the looks of the Des Moines Register and other papers, this is not the case. A recent report released in the journal Science claims that corn-based ethanol will in fact increase the amount of greenhouse gas (GHG) emissions. There are a few problems with this report that makes it smack of Pimentel. Let's be clear, I am totally for responsible scientific work, and I'm not claiming that these researcher's numbers are incorrect, however, their assertions are incorrect.
The reports released today and by Pimentel are incorrect because they incorrectly label ALL corn-based ethanol production. Pimentel used corn yields from Florida and New Mexico (average for the entire United States), along with the amount of fertilizer and water that would be needed to grow the corn in those states. This is wrong because no one is contemplating growing corn in those states -- that is where cellulosics, wind, or solar will prevail. So Iowa, Nebraska, Illinois, and Minnesota -- the states where corn is grown for ethanol are not correctly represented in Pimentel’s study.
This latest study is incorrect in representing biofuels, particularly in the United States, because it claims that deforestation due to biofuels will increase GHG emissions. Let me be clear, the expansion of sugar cane in parts of Brazil, Palm Oil in Indonesia, and other examples in other areas of the world is a problem that should be closely monitored. This does not and will not happen in the United States so the researchers, by using numbers like "a 50% increase in GHG emissions," is like taking some kind of crude average that makes little sense and should have little to no impact on the United States. At this time, we import very low amounts of biofuel. 17.4 million gallons of ethanol, in fact, was imported into the United States last year. 17.4 million!!! For you math geeks out there, that's a whopping 0.25%. The United States DOES NOT import its ethanol, thanks in part to good policies such as an import tariff that prevents tropical contries from exporting ethanol grown on deforested land. What these researchers should be doing is making sure that the corn grown in the Midwest and the cellulosic feedstocks that will be used in the future are benefiting the GHG emissions over gasoline. If they had done that, they would find a value commonly agreed on as between 16% to 20% decreased GHG emissions for biofuels compared to gasoline, rather than focus on the kind of headline-grabbing research that they did, the whole United States and the world would be better off. If Indonesia is causing increased GHG emissions because of their biofuel usage, or India's biofuel usage, than THEY SHOULD stop producing biofuels, not the United States.
And finally, I know I said this would be short but looked what happened. A final point, though, is that the real thing that is lost in this bickering over GHG emission reductions is that ethanol and other biofuels were never meant to be a monolithic fuel. I mean this in two ways -- One is that ethanol is to be used in conjunction with new technologies such as hybrids, turbocharged engines, and general conservation to reduce our use of petroleum. Although greenhouse-gas emission reduction is a big part of the reason for this reduction, it is definitely not the only reason. 1) Energy independence in a world that may be approaching a general decrease in oil supply. 2) National Security in a world ravaged with wars and hostile dictators in most oil-rich regions. 3) Agricultural Security in how much ethanol has meant to the Midwest and the United States as a whole to agriculture. 4) Decreased GHG emissions, which is approximately 16% for corn-based ethanol grown in good old Iowa.
So before a researcher goes and tells you that the nitrogen fertilizer, water requirements, and low yields to grow corn in Oklahoma will result in higher GHG emissions than oil, think about what they are saying. Who cares!! What's that got to do with the price of tea in China? Tell us something that is relevant or don't say anything at all. The report in the journal Science is misleading and should be carefully analyzed to realize just how fantastical the estimations that they use could somehow encapsulate all corn-based ethanol production.

For the report in the Des Moines Register, follow the link below:

Coskata Update

Here's a little update on the movement of GM and Coskata to bring cheap cellulosic technology to the mainstream with commercial scale production:
Coskata has teamed with a Kansas-based company named ICM with the hopes of building a commercial scale cellulosic ethanol plant by the later part of 2010. ICM is a company that specializes in ethanol plant design, engineering, and production, and will help Coskata move from the research phase into the production phase for ethanol. Although the Coskata/GM team is moving steadily forward, 2010 is still a couple years off and they are not the only ones beginning to test their products on pilot-scale plants. Companies in Florida and Idaho are also trying their own proprietary blends and it is still too early to tell whose technology will be the cheapest, most efficient, and win out in the end.

Monday, February 4, 2008

Switchgrass Impact

CBS out of Iowa City and Cedar Rapids, Iowa, is reporting that NASA intends to spend $738,000 on a study of how planting large acreages of switchgrass might have an impact on the upper Midwest and Great Plains states. The study will be in collaboration with South Dakota State University and will look into questions posed as to how large areas of switchgrass in Northern Iowa, the Dakotas, Nebraska, and Western Minnesota might have an impact as the ground is switched from corn/soybean rotations into switchgrass.

Although I think that this problem is relatively limited, since land fertile enough for corn/soybean rotations probably will not be wasted by converting the land into a switchgrass field that will yield less net profit to the farmer, I am pleased to see that the possible pros and cons of switchgrass are being aggressively looked into before undergoing a large shift in Midwest agriculture. The study will answer questions into the possibilities that large stands of switchgrass might increase the occurance of wildfires and could affect seasonal weather patterns. Even if they come to these conclusions, wouldn't restoring much of the upper-Midwest to perennial prairie grasses simply be a reversion to previous weather patterns? For this reason I will be interested in learning the results of this report.