A green storm in a tea-cup?

The fledgling algae biofuel industry has recently been upset by a new study by Clarens et al of the University of Virginia, which argues that “conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions and water, regardless of cultivation location.” The report goes on to add that the large environmental footprint is driven by upstream impacts such as the demand for CO₂ and fertilisers. However, it also states that these impacts can be reduced by flue gas utilisation and more significantly, the use of wastewater treatment.

The need for fertiliser is particularly worrying, given the high-embedded energy that it represents. This is because one of the main concerns regarding biofuels in general is the amount of energy they require, compared to the amount they actually produce, more commonly referred to as the energy return on energy invested (EROEI). In some cases, such as corn ethanol in the US, this can actually be negative, making such activities questionable and utterly reliant on subsidies and pork-barrel politics.

Interestingly, Mary Rosenthal, executive director of the Algal Biomass Organisation, has criticised the report for not assuming that algae farms would not be near a source of CO₂. This is a key factor in boosting algae yields as a final step in photosynthesis has difficulty discriminating between carbon dioxide and oxygen and if an oxygen molecule is used, then a cycle is wasted in a process called photorespiration. Hence, increasing the concentration of CO₂, results in less wasted cycles of photosynthesis, dramatically increasing the efficiency of the overall process.

She also claims that many cutting-edge algae companies have moved beyond first-generation pond cultivation systems, which are the focus of the report, highlighting the difficulty of conducting scientific studies in a rapidly-developing field, which by necessity has to keep its cards close to its chest. Andreas Clarens, the report’s lead author, has said that he used the latest data available (about a decade old), to produce the study and said that “Everybody talks about the next generation – what is the next generation?” he said. “I’d be happy to model it if somebody produces it.”

Funnily enough, a partnership might be on the cards as the Algal Biomass Organisation is now investigating the possibility of releasing data for a follow-up study. It’s fair to say that this might well be in the interests of the industry, which has often been accused of hype and making a very technically-challenging approach look easier than it is in reality. Given the need for often-scarce funds from investors and venture capitalists, this is sadly rather understandable, but requires that the industry works together to prevent investor confidence from being shaken.

Although the industry has had its share of ups-and-downs, there are definitely some signs that on the whole it is making progress. At first glance, the two most important indicators are the fact that oil prices have rebounded and the decision by Exxon Mobil to get involved. The former is crucial, given that if oil prices had remained depressed for a long time, then investor interest would have dried up, as the economic incentive for biofuels would have evaporated. This nightmare scenario occurred back in the days of the Carter Administration, when the energy crisis triggered by the Iranian revolution sparked a dramatic rise in the price of oil and as a result boosted interest in algae biofuels. When the price of oil dropped back to pre-crisis levels, the programmes were abandoned. This was a bitter blow as a great deal of research was conducted, but much of the knowledge, including an impressive bank of algae strains was lost.

Exxon Mobil’s decision to launch an impressive new algae biofuels programme in partnership with Synthetic Genomics Inc back in July matters given that the world’s biggest private oil company doesn’t do anything without a hard look at the facts and when it does, it does so in a big way. The fact that it sees significant value in this sector must be extremely encouraging for those in the industry.

Why should the power sector care? Well for one thing, algae systems can offer significant savings by reducing CO₂ and other emissions and the resulting biomass can be burnt as fuel, essentially providing a boost to efficiency. However, such systems pose many practical challenges and can take up a significant area given the need for solar energy. The fact that the process relies on photosynthesis limits CO₂ emissions reductions to daylight hours.

There is also the greater picture to consider. The days of oil are numbered and for the world’s economies to move to a cleaner energy supply chain without crashing, there is a clear need for technologies capable of bridging the gap. Given that according to Greg Mitchell of the Scripps Institution of Oceanography, “Algae [in ponds] on around 20m acres of land would supply all of the US’s transportation fuel needs – that’s a small fraction of the total amount of agricultural land, which is something over 900m acres,” the potential is clearly there. Let’s hope it becomes a reality.