Horse Feeds or Horsepower: Evaluating the Best Use of Grain

With easily accessible fossil fuel supplies becoming harder to find, the energy industry has looked at alternate sources of power for the millions of cars and trucks on America’s highways. Technologies have been developed and refined for deriving vegetable-based fuels from corn, soybeans, and sugarcane, agricultural products that previously were used mostly for human and animal food. This situation has led to increased market competition for these crops, pushing prices up for a finite supply even as more efficient farming practices have boosted production.

The manufacture of crop-derived fuel is probably not yet at its maximum efficiency, but it will need to improve significantly to equal the energy return on investment (EROI) of conventional oil. In other words, it takes energy to make energy, and a low yield of power equates to an expensive and inefficient use of raw materials.

Energy-consuming steps in producing conventional oil include drilling, pumping, and refining. World production in 2011 was about 69 million barrels a day, and EROI was 16. In contrast, the making of ethanol from sugarcane, the source of molasses used in sweet feeds for horses, has the highest EROI from agricultural products with a score of 9. This reflects the energy used to grow, harvest, transport, clean, crush, ferment, and distill the final product, which totals about 0.4 million barrels per year worldwide. Biodiesel from soybeans has an EROI of 5.5, and ethanol from corn is rated at only 1.4.

Mileage return on production energy investment follows the same curve, with cars fueled by traditional gasoline traveling 3,600 miles per gigajoule of energy expended in fuel production. Sugarcane-based ethanol produced with the same energy expenditure will send a car 2,000 miles, while soy-based biodiesel will power the same car for only 1,400 miles. Consumption of an equal amount of energy to produce corn-based ethanol would yield only about 300 miles driven.

With a ballooning world population, grains are in high demand, both for human table food and to feed animals (including horses) destined for human consumption. Natural sources of energy—wind, solar, and hydroelectric, among others—can be used to produce electricity that has the potential to be an extremely efficient way to power cars. An electric car running off the U.S. electric grid can travel 6,500 miles, more than three times as far on the same gigajoule of production energy as the car fueled by sugarcane-derived ethanol and more than 20 times as far as the car fueled by corn-derived ethanol. EROI for hydroelectric power is better than 40 and wind-based power has an EROI of about 20, both better than the EROI of 16 for conventional oil.

So what does this information have to do with feeding horses? The U.S. is still in the early stages of developing alternate forms of energy, but these figures from the International Energy Agency, U.S. Energy Information Administration, and U.S. Department of Agriculture may presage a trend. In future years, we may see less use of corn, soybeans, and sugarcane for the production of biofuels. More of these crops would be available for consumption by horses and other animals, which could lead eventually to lower prices for horse feed products.