Tuesday, May 01, 2007
Petroleum and Natural Gas Watchby Michael Vickerman, RENEW Wisconsin
April 30, 2007, Vol. 6, Number 7
Discussions of the net energy balance of grain ethanol tend to gravitate toward the fossil fuels used for growing and shipping corn. Somewhat overlooked in the net energy return debate are the quantities of natural gas and electricity consumed at ethanol refineries, which are substantial.
An ethanol refinery that produces 50 million gallons a year burns about 50,000 therms of non-renewable natural gas a day for process heat. This is no trivial expense. Using today’s prices, a refinery operator would need to budget at least $15 million over the next 12 months to secure enough fuel to keep that plant running nearly every hour of the year. After corn, natural gas is the second-largest cost component of ethanol production.
That plant also exerts, on average, a 5 megawatt load on the electrical grid. The quantity of electricity consumed at that plant could support nearly 6,000 households in Madison, Wisconsin. About 75% of the electricity from Wisconsin’s power grid comes from coal combustion.
Whether the goal is to reduce greenhouse gas emissions or enhance energy security, it makes little sense to pin our hopes on an agricultural commodity that has such an outsized appetite for fossil fuel-derived energy. When all is said and done, what this biofuel represents is the repackaging of stored energy (coal, petroleum and natural gas) into a land-intensive flow product (corn). Even though several months’ worth of sunshine goes into the production of corn, the amount of usable energy contained in ethanol is barely higher than would have been available from using the fossil energy directly.
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1 comments:
The author of a letter to the editor of the La Crosse Tribune, reached the same conclusion:
I must take issue with the Sparta residents’ blue T-shirts with the words: “The Right Answer, The Wrong Place” —that they wore to oppose a new ethanol plant in that city’s industrial park.
Heaven knows the U.S. needs new sources of fuel for our inefficient cars, and it is true that for us here corn is the least cost feedstock available for ethanol production.
But there are serious problems. From a global perspective, corn-derived ethanol is relatively expensive: it costs us
20 percent more than what Brazilians spend to produce the same quantity from sugar cane. Another whammy: Your tax dollars and mine account for a 51-cent subsidy for every gallon produced.
Even more serious, producers here in the Midwest have to use abundant supplies of coal and natural gas to convert that corn: It takes the equivalent of four gallons of gasoline in order to produce five gallons of ethanol. This is no solution for global warming.
Yet a further problem: The rush across the Midwest to target our corn for ethanol production is causing grave shortages across the globe. One result is the tripling of the price of corn and tortillas in Mexico in less than a year. What will result there — hunger? social and political instability?
In short, corn-derived ethanol might yield profits for a few large interests, but it is hardly a sustainable solution.
Urgently needed are research monies to improve methods for producing cellulose ethanol from switchgrass and other sources. But corn ethanol is not good for the Midwest or the world!
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