Corn Ethanol: Still a Boondoggle

Let our journalists help you make sense of the noise: Subscribe to the Mother Jones Daily newsletter and get a recap of news that matters.

Corn-based ethanol is supposedly a green alternative to gasoline. The corn farming lobby certainly thinks so, anyway, and they’ve persuaded Congress to mandate (and subsidize) increased corn ethanol production through the year 2015.

But is corn ethanol really greener than gasoline? If you analyze total lifecycle emissions directly (i.e., including the CO2 emissions involved not just in burning ethanol, but also in producing it), the answer is yes, though not by much. But there’s more to it than just production. When you switch forest or pasture land to cropland in order to grow more corn, that releases CO2 as well, and you have to take that into account whether the farm lobby likes it or not. (And they don’t.) The chart on the right shows the effects. So what’s the conclusion? A new paper in BioScience1 takes a fresh look at what the market response is to increased corn production, including (a) reduction in food consumption due to higher food prices, (b) intensification of agricultural production, (c) land use change into cropping in the US, and (d) land conversion in the rest of the world. The paper suggests that previous estimates of induced land use changes (ILUC) have been too high, but:

Using straight line amortization over 30 years of production at current fuel yields [] results in ILUC emissions of 27 g CO2 per MJ….[A]dding our lower estimate of emissions to the direct emissions from typical US maize ethanol production (about 65 g CO2e per MJ) would nearly eliminate carbon benefit of this biofuel relative to typical gasoline (94-96 g per MJ).

(Note: MJ = megajoule, a unit of energy.) In other words, even giving corn ethanol the maximum benefit of the doubt, it’s still no greener than gasoline: it releases about 92 grams of CO2 per megajoule of energy compared to 94-96 for gasoline. What’s more, if you assume a more reasonable 20-year amortization period, corn ethanol’s greenhouse gas emissions are even higher. And if you don’t assume that people eat less thanks to increased corn ethanol production, but instead just spend more on food, it goes up even more.

Bottom line: corn ethanol is no greener than gasoline. In fact, it’s almost certainly less green, and at the very least, there’s no urgent need for the U.S. government to pay billions of dollars to subsidize its production. Too bad Iowa is the first state on the primary calendar every four years, isn’t it?

1No link yet. I’ll add one if and when it’s available. UPDATE: It’s not online yet, but the reference is BioScience, March 2010 / Vol. 60 No. 3.

IT'S NOT THAT WE'RE SCREWED WITHOUT TRUMP:

"It's that we're screwed with or without him if we can't show the public that what we do matters for the long term," writes Mother Jones CEO Monika Bauerlein as she kicks off our drive to raise $350,000 in donations from readers by July 17.

This is a big one for us. It's our first time asking for an outpouring of support since screams of FAKE NEWS and so much of what Trump stood for made everything we do so visceral. Like most newsrooms, we face incredibly hard budget realities, and it's unnerving needing to raise big money when traffic is down.

So, as we ask you to consider supporting our team's journalism, we thought we'd slow down and check in about where Mother Jones is and where we're going after the chaotic last several years. This comparatively slow moment is also an urgent one for Mother Jones: You can read more in "Slow News Is Good News," and if you're able to, please support our team's hard-hitting journalism and help us reach our big $350,000 goal with a donation today.

payment methods

IT'S NOT THAT WE'RE SCREWED WITHOUT TRUMP:

"It's that we're screwed with or without him if we can't show the public that what we do matters for the long term," writes Mother Jones CEO Monika Bauerlein as she kicks off our drive to raise $350,000 in donations from readers by July 17.

This is a big one for us. So, as we ask you to consider supporting our team's journalism, we thought we'd slow down and check in about where Mother Jones is and where we're going after the chaotic last several years. This comparatively slow moment is also an urgent one for Mother Jones: You can read more in "Slow News Is Good News," and if you're able to, please support our team's hard-hitting journalism and help us reach our big $350,000 goal with a donation today.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate