Biofuels: Balancing The Equations

mostly-hidden frog grendelkhan
Algae-covered Frog

The biggest energy stories in August were about fuel cell-related breakthroughs and big solar projects. But the world of biofuels had some big news percolating as well. The beauty of biofuels, of course, is that they provide us with that extremely energy-dense liquid that we already know how to use (that is, gasoline, diesel, and ethanol), by sucking CO2 out of the atmosphere using solar energy.

In this post I highlight some of the biofuel-related items that caught my eye in the past few weeks, from algae that make diesel from atmospheric CO2 and sunlight, to harnessing bacteria and microbes as our refineries. This is just a small slice of the activity going on in biofuels, of course. Just as in solar PV, and batteries, and fuel cells, and wind, and alternative energy investing, there’s an ever-increasing flood of news every week. If I’m missing one of your favorites, please let me know in the comments!

Researchers at the University of Virginia are hoping to use algae to create biofuels that suck more CO2 out of the atmosphere than they use to create fuel. Algae photosynthesis to transform carbon dioxide and sunlight into energy so efficiently that they can double their weight several times a day, producing diesel-like oil in the process that can be burned directly in diesel engines or further refined into biodiesel.

Researchers have a plan to greatly increase algae oil yields by feeding the algae extra carbon dioxide (the main greenhouse gas) and organic material like sewage, meaning the algae could simultaneously produce biofuel and clean up environmental problems.

“We have to prove these two things to show that we really are getting a free lunch,” said Lisa Colosi, a U.Va. professor of civil and environmental engineering who is part of the interdisciplinary research team.

Another potential source – further in the future – of biofuels is bacteria – cyanobacteria in particular. Cynanobacteria were responsible, millions of years ago, for creating the hydrocarbons we currently pump out of the ground. At a recent workshop focusing on the photosynthetic reaction centers of cyanobacteria, organised by the European Science Foundation (ESF), Eva Mari Aro, the vice-chair of the conference, pointed out the universal expectation that photosynthesis-based forms of clean energy will represent a significant portion of the energy mix in the future. 

However, the feedstocks used for biofuels today, such as corn for corn-based ethanol, typically convert only about 1% of the incident solar energy they receive into biomass. Cynanobacteria are capable of much higher conversion rates, up to 10%. In a report on the ESF conference, Science Daily notes:

There is the potential to develop dedicated systems, whether based on cyanobacteria, plants, or artificial components, capable of much higher efficiencies, reaching 10% efficiency of solar energy conversion. This would enable enough energy and fuel to be produced for a large part of the planet’s needs without causing significant loss of space for food production.

Attendees at the ESF conference discussed several potential approaches for this program, including:

… the idea of an artificial leaf that would simulate not just photosynthesis itself but also the ability of plants to regenerate themselves. … A future aim is to build an artificial leaf-like system comprised of self-assembling nanodevices that are capable of regenerating themselves – just as in real plants or cyanobacteria. 

“Fundamental breakthroughs in these directions are expected on a time scale of 10 to 20 years and are recognized by the international science community as major milestones on the road to a renewable fuel,” said Aro.

Finally, a much nearer-term solution than either of the above items is Amyris Biotechnologies. They are engineering customized microorganisms to produce high-value compounds, from renewable biofuels to pharmaceuticals. One of their first products will be a diesel compound, which initially will be mixed with conventional diesel in a 50/50 proportion. Their first product, meant to be a proof of feasibility for their microbe-based process, is the production of artemisinin, an anti-malaria drug:

Artemisinin has been extracted from finely ground sweet wormwood for more than 2,000 years as a treatment for a variety of ailments, but the method is expensive, time consuming and limited by access to wormwood, found mainly in China and Vietnam. By inserting genes from three separate organisms into microorganisms, Amyris’ synthetic biologists have created a process by which artemisinin can be cheaply produced. Amyris will take no profit from the sales of this product to the developing world.

For more on Amyris, their technology, and the artemisinin project, I recommend this talk by John Melo, the CEO of Amyris, from the Stanford Entreprenuerial Thought Leaders series in Spring 2008.

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