Ethanol and Energy Balance

By Deane Barker on July 30, 2005

Study says ethanol not worth the energy: This is a couple of weeks old, but still a bummer of a deal for the Midwest. Ethanol is kind of the Darling of the Dakotas given all the corn around here. But, sadly, it seems as though it’s not a terribly efficient way to produce energy.

But researchers […] it takes 29% more fossil energy to turn corn into ethanol than the amount of fuel the process produces. For switch grass, a warm weather perennial grass found in the Great Plains and eastern North America United States, it takes 45% more energy and for wood, 57%.

It takes 27% more energy to turn soybeans into biodiesel fuel and more than double the energy produced is needed to do the same to sunflower plants, the study found.

So, the bottom line is that we’re losing power when we try to make these alternative fuels. But aren’t we losing power in general? Don’t we lose energy when we convert oil into gasoline?

Believe it or not, but this goes back to to the quasi-religious discussion we had about entropy and thermodynamics. There’s no way to have a perfect transfer of energy from one medium to another — there’s always going to be waste and loss. There just seems to be more loss in some mediums than others.

Wikipedia calls it “Energy Balance”:

When comparing fuel production, energy balance is the difference between the energy produced by a 1 kg of the fuel (i.e. biodiesel, petroleum, uranium ) and the energy necessary to produce it ( extraction (e.g. drilling or cultivation of energetic plants), transportation, refining etc).

The article on fuel alcohol has a good discussion on the energy balance of the various flavors.

Not surprisingly, the American Coalition for Ethanol disagrees with this study. In their Talking Points, they address it, saying:

Ethanol has a positive energy balance, meaning the ethanol yields more energy than it takes to produce it. It is an efficient fuel made through an efficient process. […] It takes less than 35,000 BTUs of energy to turn corn into ethanol, while the ethanol offers at least 77,000 BTUs of energy. Ethanol’s energy balance is clearly positive. […]

One faulty, outdated study shows ethanol’s net energy balance to be negative. That research uses fundamentally flawed, decades old data that is not valid considering today’s efficiencies in agriculture and in ethanol production.

So who’s right? Depends on who’s spinning the issue, I suppose.

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  1. Just becuase it takes energy to produce gasoline doesn’t mean it’s energy negative. If it takes 10,000 BTU to produce 10,001 BTU it is not energy negative. It’s extremely innefficient, but it isn’t negative.

  2. Hawai’i has experimented with burning sugarcane to generate steam for power generation. It seems to me that cropland might be more suited to growing something that burns efficiently.

  3. Ethanol will not fail very quickly for sure. It is so government subsidized that the few that get in on funding the plants make excessive returns.

    I have done some research on it and it is a bogus energy source, but due to govt subsidies and the farm programs, will not fail…at least yet.

  4. The same topic was brought up on a couple of weeks back. One of my best friends from back home, who has a PhD in industrial microbiology that studies exclusively in the ethanol industry, says the article is bogus and they’ve found ethanol engery returns to be 1.7:1 using the most current methods — and that takes into account the transportation, waist, fuel economy etc…

  5. In the end, this has nothing to do with entropy or thermodynamics — I was confused.

    What “energy balance” refers to is how much energy it takes to make a BTU of corn (sugar, whatever) into a BTU of fuel. The actual energy contained in the corn doesn’t change — this just refers to how much energy it takes to “release” that energy as fuel.

  6. I was reading an article about this in the local paper, and when they calculate the energy balance, they even calculate the energy required to grow the corn, whch makes sense since they must calculate the the energy required to drill for oil.

    This means that farming technology plays very strongly into the energy balance of ethanol. If you can find a more efficient way to farm corn, then you can conceivably lower the BTU expended per unit, thus improving the energy balance of the final product.

    (The only time this theory would be out of whack is if the corn was surplus, meaning it was grown for some other use, but not used, so the energy expended to grow it was a sunk cost.)

    This is the argument at the heart of the negative report on ethanol. The ethanol industry claims that the farming technologies studied in the report are old and outdated, and new methods and technologies are much more efficient.

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