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The Best Science Writing Online 2012
Showcasing more than fifty of the most provocative, original, and significant online essays from 2011, The Best Science Writing Online 2012 will change the way...
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If you flew from Houston to Chicago on November 7, your jet might have been fueled by something new—specially grown algae.
United Flight 1403 burned a blend of traditional petroleum-based jet fuel and bio-jet fuel refined from algal oil.
And on November 9, Alaska Airlines flew the first of a planned 75 flights on a blend of regular kerosene and synthetic fuels made from used cooking oil.
Bio-jet fuel has gone commercial.
Over the last five years, Boeing, the U.S. Air Force and Navy, Honeywell UOP and others have systematically tested and advanced the alternative fuel. Bio-jet fuel has been made from the plants jatropha, camelina and others.
With new regulations on CO2 emissions expected in the E.U., cutting carbon is a new flight deck priority. Bio-jet fuels are at least six times more expensive for now, but also allow airlines to combat climate change—the CO2 spewed by burning the bio-jet fuel is equal to the CO2 absorbed during plant growth. And planes fly further on the new fuel.
In fact, since July European airlines have been flying on bio-jet blends. Seems like they’re really taking off.
—David Biello
[The above text is a transcript of this podcast.]
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7 Comments
Add Comment"the CO2 spewed by burning the bio-jet fuel is equal to the CO2 absorbed during plant growth. And planes fly further on the new fuel." Did I miss something in science class? I was sure all CO2 was equal no matter the source.
Reply | Report Abuse | Link to thismich71, according to analysis, bio-fuels have higher energy densities than conventional jet fuel. That means "more energy per unit mass or volume". http://www.jatrofuels.com/306-0-Bio+Jet+Fuel.html For the same reason, you'll get better gas mileage with pure gasoline than with ethanolated fuels--gasoline has a higher energy density than ethanol.
Reply | Report Abuse | Link to thisAll CO2 may be equal in terms of its effect on the climate, but the difference here is that the bio-fuel is being produced from algae, rather than mined out of the ground. Like all photosynthesizers, algae take CO2 out of the environment as they grow, and the amount they take out is equal to the amount they then contain. By burning the algae (or some derivative), you can only put back in the environment as much carbon as you took out--that is, bio-fuels have a "closed" carbon cycle: you grow the algae, then burn the algae, then grow more algae, while the carbon just goes in a circle from air to algae and back again.
By contrast, when we use fossil fuels, we take carbon that has been sequestered below ground (thus, not environmentally significant), and dump it into the environment, resulting in a net increase of environmentally active carbon.
For algae to grow, you need to supply other nutrients than CO2. Where do these nutrients come from? Oil? It is clear that algae are not the perfect solution claimed.
Reply | Report Abuse | Link to thiseco-steve:
Reply | Report Abuse | Link to thisNo solution will be perfect, nor will any solve the problems of all energy sectors. Given the alternatives, though, algae-derived biofuels are pretty attractive compared to other second-generation bio-fuel stocks. For example, some technologies are up to 100 times as productive in terms of oil produced per unit land area devoted to production http://en.wikipedia.org/wiki/Algae_fuel
As to the source of the feedstock nutrients, for example, at least one technology uses untreated _wastewater as the nutrient source, producing partially purified water as a by-product--and nutrients extracted from the algae during oil production can be recycled back into the algae ponds, creating a potentially closed-loop production system :-)
http://www.ideals.illinois.edu/handle/2142/16823
Please lookup the "fallacy of the perfect solution"
Reply | Report Abuse | Link to thisThe science is now clear : Cultivating algae for oil absorbs 15 times more energy than it produces!
Reply | Report Abuse | Link to thisBut there is one solution : Make biodiesel through the pyrolysis of algae harvested from the sea. Or use it to make biochar and hydrogen.
See www.eprida.com or look up 'International Biochar Initiative'. Sole condition : The price of a ton of CO2 must be at least $28.
eco-steve said: "Cultivating algae for oil absorbs 15 times more energy than it produces!"
Reply | Report Abuse | Link to thisIf true, that's interesting, eco-steve. Do you have a reliable source that shows evidence in support of your allegation?
Everything that I've read suggests that algae are already efficient sources of biofuel, and that the technology is rapidly evolving to become even more efficient. See here for a round-up http://peswiki.com/index.php/Directory:Biodiesel_from_Algae_Oil