Understanding the fundamental ethanol problem

The use of non-renewable resources is unsustainable, but the production of ethanol does not reduce the use of fossil fuel.

Recently, a significant portion of the unsustainable corn grain in the U.S. has been mandated to be transformed into ethanol ostensibly to reduce the use of fossil fuels. Alas, it does not.

Over the last century, corn (and other crops) transformed from plants that utilized primarily renewable solar energy to plants that rely on non-renewable fossil fuel. At least half the corn yield can now be attributed to modern inorganic fertilizer. The use of non-renewable resources in this manner is, of course, unsustainable, but nevertheless justifiable to prevent the starvation of billions of people while we figure out how to make fertilizer in a more sustainable way. It is largely because of the conversion of fossil fuel energy from fertilizer into food that humanity has avoided global famine.

Understanding the history of converting natural gas

To understand why ethanol does not necessarily lead to a reduction in fossil fuel use, it is helpful to go back to 1909 when Fritz Haber discovered the chemistry of converting natural gas into ammonia. This led to inorganic ammonia-based nitrogen fertilizers. Before the invention of inorganic fertilizer, corn yield was around 30 bushels per acre. The use of improved genetics designed to pull most of the energy from fertilizer, not from the sun, caused yields to soar to 150 bushels per acre (200 in the best fields). Modern fertilizer allowed the Green Revolution to feed additional billions of people.

Energy Return on Investment

A well-documented report, written by T.A. Kiefer of the Waterloo Institute for Complexity and Innovation, discusses how the production of ethanol does not reduce the use of fossil fuel.

Kiefer compares petroleum to ethanol using Energy Return on Investment. EROI is the ratio of energy produced to energy consumed. When producing petroleum diesel and gasoline, the EROI is at least 8 to 1. In other words, the investment of a barrel of energy in petroleum discovery, production, refining and delivery yields 8 barrels of energy.

The EROI of corn ethanol is only 1.25 to 1. In other words, the investment of one barrel of energy in the production of corn and the distillation of ethanol yields 1.25 barrels of energy. The slight energy profit is not in liquid fuel (in that area ethanol breaks even). The gain is in the production of a feed co-product, distillers dried grains with solubles.

To produce the same gain of 8 barrels of energy yielded by petroleum with a single barrel of energy requires 8/.25 or 32 barrels of input energy for ethanol. After expending the 32 barrels of input energy the production of ethanol is considerable, but the net increase in liquid fuel is zero. The gain is solely in DDGS.

It would be more efficient to grow more soybeans to replace the DDGS produced by ethanol production rather than go through a massively disruptive process which, in the end, yields a lot of ethanol but no net additional liquid fuel. The liquid fuel energy equivalent going in is roughly equivalent to the liquid fuel energy coming out of the process. In addition, the process produces three times as much carbon dioxide while consuming 1,000 times as much water.

Ethanol production has led to damage in animal agriculture

The process of producing ethanol has led to well-documented damage to the animal industries as well as the deterioration of food security worldwide and huge environmental costs. What is not well documented is the utter futility of the policy. Transformation of fossil fuel in the form of fertilizer to corn and back again to a fossil fuel substitute (ethanol) is a bridge too far and represents a willful ignorance of the second law of thermodynamics (some fraction of useful energy irreversibly becomes useless energy every time energy is converted from one form to another). It would be far better to use fossil fuel directly than to transform it twice.

Kiefer concludes by saying, “Trying to biofuel our way to energy independence is like medieval physicians trying to bleed their patients back to health. It is time to stop the bleeding … An effective energy strategy must exploit rather than defy the laws of nature …”

 

 

Barrels of energy investment v. barrels of energy return

 

Petroleum

Ethanol

 

 

 

Energy Return on Investment

8:1

1.25:1

Equivalent gain

8:1

40:32

Liquid fuel net gain

8

0

Feed co-product

0

8

 

 

 

Total output CO2

9,600 lbs.

37,100 lbs.

Total input H2O

2,500 gallons

2,700,000 gallons