Biofuel from Algae
July 31, 2009
Talk of biofuel as an alternative to oil was all the rage when crude was skyrocketing towards $200/barrel. About the same time, the world was undergoing a food crisis. The diversion of agricultural acreage to produce biofuel crops exacerbated the crisis and increased tension between biofuel proponents and food security advocates. The most obvious way to reduce tensions between those promoting biofuels and those who believe that it’s wrong to convert land used for food crops into biofuel acreage is to harvest a biofuel source that isn’t used for food and can be grown where food crops can’t be grown. Early last year, I wrote a blog about how algae could fit that bill [The Potential of Pond Scum]. That post focused on an article in BusinessWeek [“Here Comes Pond Scum Power,” by Gail Edmondson, 3 December 2007] that claimed “algae farms don’t require huge volumes of freshwater, nor do they tie up land that could be used for food crops. Algae flourish in saltwater or even wastewater and grow up to 40 times faster than other plants. Compared with current energy crops, algae have ‘the potential to deliver 10 or 100 times more energy per acre,’ says Ron C. Pate, a technical expert at Sandia National Labs.” At the time I wrote “if that sounds too good to be true — well … it is. Edmondson admits algae biodiesel isn’t practical yet. “Bringing down the cost of producing algae oil in commercial volumes—billions of gallons—is still a big challenge. ‘The scale required to grow algae to a meaningful dimension is staggering,’ says Bill Green, managing partner at VantagePoint Venture Partners.”
Research into algae-based biofuels has continued apace and ExxonMobil has reported “that it will sink up to $600 million in an algae-to-fuel startup founded by genomics pioneer J. Craig Venter [“Exxon Funds Biofuels,” edited by Michael Arndt & Cristina Linblad, BusinessWeek, 27 July 2009 print issue]. Exxon claims “that an internal study has found that algae is the only alternative that can be commercially successful.” You might not want to tell Brazilian sugarcane growers that their efforts aren’t successful; at least not until they are no longer making a profit. I suspect what Exxon’s study found was that algae could be grown commercially in greater amounts in various geographies than other biofuel crops. The Economist provides a more detailed look into what Dr. Venter is doing and why Exxon Mobil is willing to invest in his efforts [“Craig’s twist,” 18 July 2009 print issue].
The article begins by noting that ExxonMobil’s chief executive dismissed biofuels as “moonshine” just about the same time that British Petroleum (BP) was branding itself a “Beyond Petroleum” company. Now that the shine has worn off biofuels (because oil prices are down and the food shortage produced numerous critics), some companies are having second thoughts about expanding their biofuel efforts and “Exxon seems to be going the opposite way yet again.”
“The beneficiary of this largesse is Synthetic Genomics, a firm based in San Diego that is the commercial vehicle of Craig Venter. Dr Venter may be familiar to readers as the former head of Celera Genomics, which ran a privately financed version of the human genome project during the late 1990s, and before that as the leader of the team which produced the first genetic sequence of a living organism (a bacterium called Haemophilus influenzae). In this case, though, the money will be thrown at neither people nor bacteria, but algae. At the moment, most biofuels are either ethanol, usually made from sugarcane or maize, or biodiesel, made from plant oils. But many people hope that will no longer be true in ten years’ time. By then, the expectation is, biofuels will chemically resemble the stuff that pours out of existing oil refineries—ie, hydrocarbons. The question is, how do you get there from here? Dr Venter thinks he knows the answer. He proposes the industrial-scale culturing (biomanufacturing, as he describes it, rather than farming) of single-celled algae that have been genetically engineered to turn out fuel-ready hydrocarbons. He is by no means the only person to be working on the idea of turning algae into biofuels, but he has one or two particular ideas about how to do it. The most important of these is to get the algae to secrete their products into the culture medium in which they are being raised. Many algae make oil, which they store as a foodstuff against an uncertain future. But they do not squirt it out of their bodies. That would be pointless.”
Of course, we train animals to do all sorts of pointless things — like roll over — in order to get a reward. But single-celled algae aren’t exactly the best subjects for training using the tried-and-true reward method. So Dr. Venter tried another approach.
“Dr Venter … succeeded in engineering a secretion pathway from another organism into experimental algae. These algae now release their oil, which floats to the surface of the culture vessel. That is why he refers to the process as biomanufacturing. It is not farming, he reckons, because the algae themselves are never harvested (though it may be necessary to cull them if they become too abundant). The next trick, which Exxon’s money will help pay for, is to tweak the biochemical pathway that makes the algal oil (which is known, technically, as a triglyceride, and has oxygen atoms in it as well as carbon and hydrogen) so that the oxygen-containing parts of the molecules are snipped off and a pure hydrocarbon is left. After that, it will be a question of looking through the thousands of species of algae around to see which would make the best ‘platform’ for the new technology. The ideal species will be able to stand up to intense illumination (more light means faster photosynthesis) and heat (for the high levels of sunlight required will also warm things up). It will also need to be resistant to viruses, which will otherwise be a big threat to such a concentrated population of identical organisms. And if no suitable species exists, then Synthetic Genomics’s researchers will take the desirable characteristics from several and create what is, in effect, a new one.”
There are more good things about producing biofuel from algae. The algae can help reduce greenhouse gasses as it grows.
“The other raw material for photosynthesis, carbon dioxide, will be supplied as the exhaust from industrial plants such as power stations, oil refineries and natural-gas processors. That this will be captured before it can get into the atmosphere and promote climate change will be a bonus. The process will not be truly carbon-neutral (for that, the CO2 would have to come out of the atmosphere, and if the algae could use only the limited amount of the gas in natural air, they would not grow fast enough) but each carbon atom will have been made to do double duty in a fuel before it finally escapes. The result, if all goes well, will be a mixture of hydrocarbons that can be fed into the stage of the oil-refining process just before petrol and diesel emerge from the stills, and at a price that competes with the equivalent chemical mixture produced by traditional methods.”
The greatest benefit of using algae as the base stock for biofuel is that it, as noted above, doesn’t necessarily have to compete for agricultural acreage to be grown. Even if it did, Venter believes that “it should be possible to turn out ten times more fuel per hectare than can be garnered from maize.” Of course, the article notes, algae production is more capital intensive because the plants must “be force-fed with CO2.” As long as the CO2 is available, however, currently non-productive areas could be made productive. The article concludes:
“If the process really can be made to work, CO2 would go from being a polluting waste product to a valuable raw material, and it might even become worthwhile building systems to capture it and pipelines to ship it around. That really would be ironic.”
Don’t expect to pump algae-based biofuel into your tanks in near future. There remain lots of challenges. ExxonMobil, however, is beginning to believe that there is potential for biofuel beyond its use as “moonshine.”