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Behind The Algae-Biofuel Hype

Lately, investors have been getting excited about the idea of using algae to generate new biofuels. Earlier this year, ExxonMobil inked a $600 million deal with Synthetic Genomics to develop algae biofuel using a new, seemingly promising technology. (Keith Johnson offers a fuller explanation here.) But over at Earth2Tech, Katie Fehrenbacher has a excellent post asking whether this summer's hottest clean-energy fad will really reduce carbon emissions. She offers a healthy dose of skepticism:

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. …

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.

Current analyses of algae fuel vary quite widely. Some companies claim that algae biofuels offers breathtaking reductions of carbon-dioxide compared with gasoline. Others are starting to tiptoe away from this claim and instead argue that algae biofuel should be viewed more as a means of reducing our dependence on foreign oil than as a way to reduce greenhouse-gas emissions. (Once again we see that "energy security" and "averting global warming" are two goals that don't always fully overlap.) But there's still no hard, reliable data out there yet.

--Bradford Plumer