Green Leader

(Editors note: Robert Rapier continues his series looking at the potential and viability of biofuels)

The recent capitulation of algal-biodiesel pioneer GreenFuel Technologies provides an important lesson for those who believe there will be a seamless transition from fossil fuels to a greener future. There are many intriguing possibilities out there, but most of them are going to end up on the scrap heap of history as these technologies scale up from the lab. If you are familiar with the history of algal biodiesel, you may know from 1978 to 1996, the U.S. Department of Energy funded a study by the National Renewable Energy Laboratory (NREL) on the feasibility of producing renewable fuels from algae. The study examined a number of strains of algae for potential lipid production, as well as those that could grow under conditions of extreme temperature, pH, and salinity.

Certain species of algae are capable of producing lipids (similar to vegetable oils), which can be pressed out and then converted to renewable diesel. Algae-based renewable diesel is an appealing prospect, as this could potentially open up biofuel production to areas unsuitable for farming. Furthermore, the estimates of the oil production potential from algae have been as high as 15,000 gallons/acre – hundreds of times greater than the per acre yield of soybean oil.

But there are some big hurdles. While the production of biofuels from algae has obvious appeal, the NREL close-out report concluded that there are many technical challenges to be overcome. A major challenge was encountered in the attempts to increase oil yields. Oil concentrations could be increased by stressing the algae and causing it to shift from a growth mode into a lipid production mode, but this resulted in lower overall oil yields because algal growth slowed. The researchers also discovered that contamination was often a problem upon moving from the laboratory into open pond systems. An obvious solution is to use closed photobioreactors (PBRs), but the capital costs for these are very high (> $100/square meter) relative to their output. This is a big problem when the chemistry suggests that based on the highest levels of solar insolation, about one gallon or so per square meter is all of the biodiesel that you might expect to produce. There are potentially ways to boost those yields higher, but all come at a cost of additional energy inputs into the system.

The NREL close-out report for the study suggested that algae could potentially supply the equivalent of a large fraction of U.S. fuel demand, but costs must come down, and technical challenges must be solved. On the subject of costs, the report noted ‘Even with aggressive assumptions about biological productivity, we project costs for biodiesel which are two times higher than current petroleum diesel fuel costs.’ More realistic assumptions result in project costs that are 10 times petroleum diesel costs. Furthermore, because of lack of data on continuous lipid production from algae, the energy return on the process is unknown. Overall, commercialization was deemed to be far away, which is why the decision was made by the DOE to terminate the program.

Therefore, when numerous companies began to jump on the algal biodiesel bandwagon, the technical challenges ensure that many – and maybe all – are ultimately going to fail to produce commercial biodiesel from algae at a competitive price. In fact, a recent cost estimate from Bryan Wilson, a co-founder of Solix Biofuels, pegged the production costs at $33/gal. This suggests that at the present time, algal biodiesel is more of a research project, with imminent commercialization unlikely. So, investors would be prudent to be cautious around the sector.

In my opinion there are other options that presently have better commercialization potential. In the next essay, I will discuss the prospects for commercialization of renewable fuel from jatropha curcas.

Robert Rapier currently employed as the Engineering Director for London-based Accsys Technologies. Robert maintains an energy blog at http://i-r-squared.blogspot.com/

Tags: Algal Fuels, Biofuel

This entry was posted on Monday, June 15th, 2009 at 9:00 am and is filed under Biofuels. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.