Improved ethanol methods increase energy yield

A USDA study cites better corn seeds, fertilizer use, and sources to power ethanol plants for the energy gain.
By MIKE HUGHLETT, Star Tribune
Advances in how efficiently corn can be converted to ethanol have led to an improvement in how much energy is squeezed from corn, according to a study released last week by the United States Department of Agriculture.
The study was based on a survey of 1,814 corn farmers in 19 states and ethanol producers in Minnesota, Iowa, Nebraska and South Dakota. It found that for every British Thermal Unit (BTU) needed to make ethanol, 2.3 BTUS of energy were produced.
That’s up from 1.76 BTUs of energy produced in 2004, a significant improvement, said Ward Nefstead, one of the study’s authors and a professor in the University of Minnesota’s Applied Economics Department.
Genetic improvements to corn seeds have increased starch levels, allowing for more energy to be wrung from corn, he said. The use of alternative energy sources to power ethanol plants — instead of natural gas — has increased.
And farmers are applying nitrogen fertilizer more efficiently, too, reducing the amount of energy needed to grow corn.
Nitrogen use on a per bushel basis has declined by 20 percent since the mid-1990s, the study said. Meanwhile, ethanol yields have increased by about 10 percent over the past 20 years, so proportionately less corn is required to make ethanol.
Ethanol has gone from being an “energy sink” — meaning it took more energy to produce than it yielded — in its early days to being a “substantial net energy gain” nowadays, according to the USDA.

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Our Take:
People close to the ethanol industry will not be surprised by the USDA’s findings. It’s thoroughly researched, well-supported conclusions show that A. farmers are becoming more efficient, and B. ethanol producers are becoming more efficient.

The next time you encounter an ethanol naysayer here is your off-the-cuff response: Ethanol has a net energy value almost three times better than gasoline. Ethanol returns 230 percent of the fossil energy inputs—that includes the entire process from planting the seed to delivering the ethanol to the fueling station. From field to wheels. And that compares to 88 percent net energy value for gasoline.

This is the trend: oil’s carbon intensity is growing every day and ethanol’s is being reduced through greater and greater efficiency.

When you add up the energy to excavate and maintain oil wells, transport crude to refineries, crack the crude and refine it down to gasoline, the petroleum companies use up 12 BTUs out of every 100 potential BTUs in order to make gasoline. There’s also the flaring of oil wells—the release of natural gas—either burning it or releasing it unburned—into the air in order to relieve pressure created by the oil well and maintain its safety.

In fact the 12 in 100 is an old number. As more petroleum comes from deep offshore wells, from strip mining of tar sands and from century-old, tapped out oil wells where heated water jets are used to force the remaining oil to the surface (a growing number of oil wells in the United States fall into this category)—oil production becomes more energy intensive, as a whole. And the 12 in 100 loss number also doesn’t include the portion of fuel used by the military that is dedicated to protecting the shipping channels that assure the free flow of oil around the world.

Then there’s the question of putting carbon into the atmosphere—the more energy it takes to capture the oil, refine it and transport it, the higher the carbon intensity. While oil’s carbon intensity is growing every day, ethanol’s is being reduced through greater and greater efficiency.

Due more to the volatility of natural gas prices over the past decade than any other reason, the ethanol industry has begun to consider—some have already adopted—biomass-based power as an alternative to natural gas. With the potential for carbon legislation arriving soon in America, ethanol plants are embracing the concept. And it’s a good move for farmers, too, with the potential to make byproducts of crop production like corn leaves and cobs and wheat straw into a revenue stream for farmers, while providing a more price-stable energy source for ethanol plants.


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