The idea of using algae to produce fuel for vehicles has been the blockbuster topic of the summer. Major deals have recently been done by heavyweights like Exxon, and Synthetic Genomics, Sapphire Energy and Bill Gates’ Cascade Investments, and more funding is in the pipeline from the U.S. government. But does that mean that algae-powered cars are going to significantly help fight global warming? Not necessarily, but maybe — it seems that, as with most types of biofuels, the overall carbon emissions reductions we could get by swapping out gasoline for algae fuels totally depends on the production process.
Here’s the rub of algae fuels: algae absorbs CO2 as it grows, and this CO2 can come from, say, power plant emissions, thus providing a productive way of recycling the carbon emissions. But when algae fuel is burned in an engine, guess what — the carbon dioxide is released. As Robert Rapier, chemical engineer, former Engineering Director for Accsys Technologies, and blogger at R-Squared Energy Blog, explained in an email to me, “carbon is only briefly sequestered until the algae are turned into fuel and burned. . . If an efficient process is worked out, what you could say is that it is at best carbon neutral, unless you are burying the algae.”
Of course a truly carbon neutral fuel would be great, compared to gas being burned by internal combustion engines, but another problem with algae is that finding an efficient way to grow and collect the algae, and then extract the oil is proving difficult. That’s part of the reason why costs are so high for the industry, and why companies like GreenFuel have struggled to make the economics work. While we don’t have the data to know for sure, it’s possible that some of these processes from startups and big oil firms could actually result in more carbon emissions than some of the fossil fuels they’re supposed to replace, if you take into account the large amount of electricity required (and thus carbon emitted) to harvest the algae from the water and then the oil from the algae.
Currently, there’s a lack of hard data in the industry because the technology is in a nascent stage and isn’t being produced at commercial scale. Algae fuel that has found an efficient process at the pilot stage could face hurdles reproducing that process economically at a commercial scale. As Rapier explained to me in response to my query about the carbon reductive nature of algae fuel: “Right now, though, nobody really knows. However, I suspect both algal biofuel and cellulosic ethanol are returning less than 1 BTU of energy for a BTU of input in practice. If true, that makes them worse than fossil fuels (but with potential to get better).”
A lot of the startups are now working on analysis of their algae fuel, but are coming up with a variety of results. Sapphire Energy says that its “[A]lgae-based fuels emit approximately two-thirds less CO2 than petroleum-based fuels at scale,” and have “significantly less than half” the carbon impact of conventional biofuels, such as corn ethanol and soy biodiesel. At the Always On conference at Stanford University last week Aurora Biofuels board member and Gabriel Ventures Partners partner Jim Long told me that algae fuels are more intended to help the U.S. reduce its reliance on foreign oil, and not necessarily intended as a way to fight climate change.
Solazyme, has gone a step further and done a carbon and greenhouse gas emissions life cycle analysis of its technology, conducted by Life Cycle Associates, using the Argonne National Laboratories GREET model. Solazyme says that “from field-to-wheels,” Solazyme’s “Soladiesel” is “85 to 93 percent lower than standard petroleum based ultra-low sulfur diesel” and has “a significantly lower carbon footprint than any currently available first-generation biofuels.” According to Rapier, however, who says he doesn’t “put any stock at all in life cycle analysis for processes that don’t exist commercially,” these analyses at pre-commercial stages are often times based on assumptions that can prove to be different at a commercial stage.
With so little data out there, I turned to the Energy Biosciences Institute, the $500 million biofuel research program set up by BP, UC Berkeley and other universities, for help. Nigel Quinn, the Group Leader for HydroEcological Engineering Advanced Decision Support at the Berkeley National Laboratory, who has just started research on these types of issues, told me he has also seen that “the results of studies by the R&D departments of these [algae fuel] companies are all over the map,” and “There are many claims being made, not all of which have been substantiated.”
But Quinn finds algae fuel to be promising. He says:
CO2 use in algae biomass systems is attractive – because it does double duty. . . We think there may be significant synergies between carbon sequestration activities such as underground injection of C02 and growth of algae on the produced water (displaced by the CO2) – and its conversion to a biofuel. This is an area we are just starting to investigate.
At the end of the day, algae fuel clearly has a lot of possibilities, but like in most emerging cleantech sectors that haven’t had a chance to mature yet, the industry needs more data, more analysis and more systems to verify the carbon reductions of its technology.