Biofuels better for Nature? Maybe not!
Depending where you are in the world you might notice signs touting the 5% ethanol in the gasoline you are buying. The idea is that biofuels [currently primarily made from corn] are better for the environment. As it turns out that might not be the case.
A new study in the journal Nature Climate Change suggests that one particular source of biofuel, corn residue [the stuff left over from corn production], should not and cannot be used to meet the new US federal mandate to ramp up ethanol production and [ideally] lower greenhouse gas emissions.
The team, from the University of Nebraska-Lincoln, was lead by assistant professor Adam Liska. The team used a supercomputer model to estimate the effect of residue removal on 128 million acres across 12 “corn belt” states. They found that just the act of removing the corn residue [again the left over from corn harvest] added 50 to 70 grams of carbon dioxide per megajoule of biofuel energy made.
[Loony hint: a megajoule is 1,000,000 joules and a joule is a measure of heat, you can read about just how much heat a joule is here.]
That means that the total emissions [from collection to burning of the biofuel] is roughly 100 grams of carbon dioxide per megajoule– or roughly 7% more carbon emission than plain ol’ gasoline. It is also about 62 grams above the 60% reduction in greenhouse emissions that is required by the 2007 Energy Independence and Security Act.
The team also showed that no matter how much or little was harvest, the rate of carbon emission was the same. “If less residue is removed, there is less decrease in soil carbon, but it results in a smaller biofuel energy yield,” Said assistant professor Liska.
The big question is, how accurate is this study? The team of researchers tried their best to find an error with the data, but there was [unfortunately] no way to change the findings.
“If this research is accurate, and nearly all evidence suggests so, then it should be known sooner rather than later, as it will be shown by others to be true regardless,” he said. “Many others have come close recently to accurately quantifying this emission.”
So what does this new research mean? Well, primarily that the green fuel source that has been the hope for a clean, renewable gas alternative might not be everything we hoped it would be.
Of course Ethanol has been plagued with problems of it’s own, such as the amount that can be safely added to gas for general car use. The fact that when the temperature drops and gas is still liquid ethanol will turn into a gel, which is why you only see roughly 5% of it in fuel now. The rise in cost of food [not just corn, but everything] because of the harvest costs involved. Or my personal favorite, it is less energy dense, meaning you will get less miles per gallon for a gallon of 5% ethanol mix gasoline than actual 100% gasoline.
This is definitely one more stumbling block to overcome. Of course there are other hopes, different types of plants for example, or more fuel efficient cars, better ways to harvest, the reduction of coal power plants to produce the ethanol are all ways to reduce the carbon footprint left.
There is also other technology like algae that produce ethanol, which to me will be the way to go in the future. Or other fuel sources like hydrogen, [which I do not agree with] or electric, which has the [dirty] battery issues to deal with. Along with the power plant emissions has to be added from the electricity to power the car.
The bottom line is really, use less, find more fuel efficient car designs and technologies and find ways to move away from oil all together. Maybe someday, however, when oil companies have enough money to dictate policy it doesn’t seem like a strong contender will be coming out of the gate anytime soon.
But that is a topic to discuss all its own.
Mega bored from my explanation of megajoules? You probably want the full article — here!
Liska A.J., Yang H., Milner M., Goddard S., Blanco-Canqui H., Pelton M.P., Fang X.X., Zhu H. & Suyker A.E. (2014). Biofuels from crop residue can reduce soil carbon and increase CO2 emissions, Nature Climate Change, DOI: 10.1038/nclimate2187