This summer, starting on its Los Angeles to San Francisco route, United Airlines will fly commercial jets using a biofuel made out of plant oil and animal fat. In 2013, United agreed to buy 15 million gallons of the fuel, produced in California by AltAir Fuels, over three years, with the option to buy more. AltAir uses discarded farm waste like tallow (rendered animal fat) plus non-edible natural oils to make biofuel that works in existing jet engines.
The AltAir fuel will be blended with traditional jet fuel, starting with a 30/70 mix. But United isn't placing all its bets on AltAir. On Tuesday, The New York Times says, United will announce a $30 million investment in Fulcrum BioEnergy — a small amount compared with the $11.6 billion United spent on fuel last year, but the largest such investment by a U.S. carrier to date. Fulcrum turns municipal garbage into aviation fuel, promising cheap green fuel from a plentiful source of raw material.
Airlines are trying to reduce their carbon emissions but alternative, sustainable sources of jet fuel aren't yet available in dependable quantities. The industry hopes to cut its greenhouse gas emissions to half their 2005 levels by 2050. Peter Weber
Advanced corn ethanol was once thought to be a viable energy alternative to filthy gasoline; a cleaner burning fuel that could someday enjoy wide-scale usage and help to mitigate climate change. Yet a new study from the University of Nebraska-Lincoln has found that ethanol made from corn leftovers may actually be more harmful to the environment than the traditional fossil fuel.
The problem is that removing "corn residue" from fields to produce cellulosic ethanol reduces the soil's ability to trap carbon dioxide, according to the study. When extrapolated to account for mass production, the incidental emissions would be about 7 percent greater than the total emissions from gasoline.
That finding puts some hard numbers behind an interesting note in the U.N.'s latest climate change report, which said "indirect emissions" from biofuels "can lead to greater total emissions than when using petroleum products."
That said, the EPA dismissed the study because it assumed all of a corn field's waste would be used for ethanol production, an assumption the EPA said was "an extremely unlikely scenario that is inconsistent with recommended agricultural practices." And the study did note that emissions could be offset by planting cover crops, so it's not guaranteed that cellulosic ethanol production using corn would have to be more harmful to the planet than gasoline. Jon Terbush