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Biofuel versus bioelectricity, and the winner is…

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May 20, 2009

The electric Tesla Roadster comes out on top of the ethanol powered Saab 9-5 in the miles ...

The electric Tesla Roadster comes out on top of the ethanol powered Saab 9-5 in the miles per acre stakes

May 20, 2009 Running vehicles on biofuels such as ethanol reduces CO2 emissions and offers a way to lessen the world's reliance on oil. While this sounds great from an environmental perspective, the energy required to produce the biofuel and the land clearing for crops that can result means biofuels aren’t necessarily the environmentally friendly solution they initially appear to be. Recognizing this, researchers have analyzed the best way to maximize the “miles per acre” from biomass and discovered that the far more efficient option is to convert the biomass to electricity, rather than ethanol. Another tick for the electric car.

Writing in a recent online edition of Science, the researchers calculate that, compared to ethanol used for internal combustion engines, bioelectricity used for battery-powered vehicles would deliver an average of 80% more miles of transportation per acre of crops, while also providing double the greenhouse gas offsets to mitigate climate change.

The researchers performed a life-cycle analysis of both bioelectricity and ethanol technologies, taking into account not only the energy produced by each technology, but also the energy consumed in producing the vehicles and fuels.

Bioelectricity was the clear winner in the transportation-miles-per-acre comparison, regardless of whether the energy was produced from corn or from switchgrass, a cellulose-based energy crop. For example, a small SUV powered by bioelectricity could travel nearly 14,000 highway miles on the net energy produced from an acre of switchgrass, while a comparable internal combustion vehicle could only travel about 9,000 miles on the highway.

Bioelectricity also offers more possibilities for reducing greenhouse gas emissions through measures such as carbon capture and sequestration, which could be implemented at biomass power stations, but not individual internal combustion vehicles.

Lead author of the study, Elliott Campbell of the University of California, Merced, says, "there is a big strategic decision our country and others are making: whether to encourage development of vehicles that run on ethanol or electricity. Studies like ours could be used to ensure that the alternative energy pathways we chose will provide the most transportation energy and the least climate change impacts."

Darren Quick

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
3 Comments

According to Wikipedia, there are almost 7.7 billion acres of arable land on the earth. If we planted it all in switchgrass, and gave each of earth's 6.6 billion people their own bioelectrically fueled SUV, each person on the earth could drive about 16,333 highway miles, and we could all starve to death. Although there are many other potential sources of energy and many other ways that we currently consume energy, I think the handwriting is on the wall: we need become much more efficient in our energy usage, have many fewer people, or give up the dream of everyone eventually living as well as people in the US. I hope we will fly in the face of our history and make a few good, rational choices about this.

proportion
27th May, 2009 @ 01:32 pm PDT

I like how burning switchgrass is made palatable by saying it is converted into electricity with no mention of how. Judging by the references to carbon capture storage, it is likely made possible through a furnace, steam boiler, turbine and generator. Why convert sunlight into vegetation, only to burn it to get the energy out. I would wager that solar power collected on the same acreage over the time to harvest and process the switchgrass for burning would be equal if not greater. Considering carbon capture techniques are still in their infancy and not at all proven this paper makes some grand assumptions. However, I do feel it serves a purpose in illustrating that ethanol is a stupid idea that stupid politicians make.

CreativeApex
27th May, 2009 @ 06:31 pm PDT

@proportion

You still have not added into your equation of Algae bio-fuels which are able to use non-arable land into fuel farms. Which are capable of achieving 2.5 - 5 times more fuel per acre as opposed to other alternative fuels. The oceans are massive CO2 absorbers which have lead to ocean acidification causing to oyster fields to dwindle, coral bleaching, and mass toxic algae (red algae in particular) blooms causing fish kills.

You could take out three birds with one stone by farming algae in the ocean due to the fact coral symbiosis relationship with algae. Which flourishes sea life with hiding spots and feeding nests of sorts. Shrimp eat algae.. Others eat shrimp.. Bigger stuff eat others.. Now finding the proper algae would not be that hard thanks to recent research and analysis of composition of strains.

Bob Dobbs
27th May, 2009 @ 06:41 pm PDT
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