On Wednesday I discussed the first part of Professor Steven Briggs presentation on biofuels. The second part of Professor Briggs presentation was specific to algal biodiesel. Like Wednesday, I will provide a bit of commentary on some of his remarks (underlined, paraphrased).
- Algal - 48 metric ton/acre/year
- Switchgrass - 12 metric ton/acre/year
- Sugarcane - 10 metric ton/acre/year
- Corn - 6 metric ton/acre/year
The information above was one of several slides that Professor Briggs used to make a point on the effieciency of algae in converting to biomass. I believe Briggs was indirectly tackling the land use issue. For those a bit removed from the biomass industry, there is a growing land use issue that both Andy B and I have heard about at recent ethanol conferences. The theory is that land use for energy will replace acreage that is currently absorbing carbon dioxide (by way of trees and foliage), converting the land from a carbon sink to carbon neutral, and thus increasing the amount of global warming. It is an interesting and complex topic, and given Briggs attention to land use in his presentation, I believe it is likely to be used as a counterargument to biomass collectively, whether it is true or not. In any event, it is becoming important politically to maximize yield per acre, as there are other thorns on the land use issue (food production, fertilizer run off, genetically-modified plants) even if this one is resolved favorably for biomass.
We need to refine biodiesel to higher grade fuels
Professor Briggs presented a wonderfully simple flow chart showing the steps from farming to fuel. There were several steps in the process where Professor Briggs noted that algal biodiesel was not yet efficient enough for commercial production, but the most interesting step for me was the refining process. Refining biodiesel is essentially maximizing the production of low molecular weight carbons and increasing the heat content of the fuel. However, there is also a third goal of refining, and that is in minimizing the production of secondary pollutants (sulfur oxides, nitrogen oxides, and chlorides). A great deal of time and money has been spent to minimize the secondary pollutants produced by hydrocarbons. Will biofuels be able to capitalize on these technologies, or will there need to be new technologies developed to reduce secondary pollutants?
One final note - Professor Briggs displayed a colorful table at the end of his presentation showing a variety of fuel sources in rows (hydrocarbons, algal biodiesel, electricity, etc.), a variety of issues with those fuels in columns (cost, security, availability, etc.) and a green (good), yellow (fair), or red (bad) symbol in each box for their impact. Teasingly simple, it also suggested that there is quite a fight amongst "green" energies - all of algal biodiesel boxes were green, while other green sources were noticeably multi-hued - despite the lack of an in-place commercial-scale techology (isn't that a bit important?). I guess competition in the green industry is no longer just limited to beating up hydrocarbons.
For a presentation on ethanol scrubbing, download the presentation below.