Page 74 - North American Clean Energy January February 2014

biopower

he Huckabay Ridge
Anaerobic Digestion Project
in Stephenville, Texas, is
currently the largest anaerobic

digestion plant in North
America

From By-product to Power

The business of turning manure into

renewable energy

By Michelle M Lantz

When thinking of horses, renewable energy likely isn’t the irst thing that

comes to mind. But, over time, the potential connection between animals and

energy has become obvious.

Fast facts
Back in the late 1800s, the horse population skyrocketed around.” Entrepreneurs are again discussing manure,

According to the United States Environmental Protection in America and around the world due to the explosion
only this time they are using new technologies to turn
Agency (www.epa.gov), some beneits of anaerobic of trade and industrial freight, personal and public the animal byproduct into energy—renewable energy.
digestion (AD) include:
transportation, and increased farming acreage.
All of this “horse power” created mounds.and The power of anaerobic digestion
• The creation of biogas, a renewable source of energy that
mounds.of horse manure. Beyond the obvious issue of Anaerobic digestion (AD) is the process by which organic
can be used similar to natural gas.
odor, additional environmental concerns stemmed from materials (such as manure) are broken down by micro-
• A reduction in methane emissions—when left to waste, the unwanted byproduct, including lies and disease, organisms, in the absence of oxygen. Used to manage
public sanitation issues, and even increased fatalities.
waste, anaerobic digestion can also be used to produce
food and other organic materials (such as manure)
decompose to create methane, a greenhouse gas with To solve the horse byproduct problem, urban fuels. he usage of animal waste for AD solves two
a global warming potential 21 times higher than carbon planners and entrepreneurs of the day began to invest environmental issues: disposing of billions of pounds of
in new technologies and new modes of transportation. manure, and creating a high-quality renewable source of
dioxide.
Slowly, over time, people relied less and less on the energy.

• Animal byproduct management. Dairy digesters, for horses themselves, and more and more on automated Currently, the largest AD facility in North America is
example, provide a management method for manure that “horsepower.”
at the Huckabay Ridge Anaerobic Digestion Project in
improves water quality, reduces methane emissions from What those pioneers didn’t predict, however, was the Stephenville, Texas. Located in a major dairy community
impact vehicles would have on our energy consumption where manure is plentiful, the Huckabay Ridge facility
manure lagoons and storage ponds, and minimizes odor.
and environment in other ways. Moreover, as the turns manure and substrate (including glycerin, grease
• A reduction in chemical usage. Using the solid residual population increased, so did the need for dairy and trap, and other organic waste) into biomethane gas
as a soil amendment can reduce the need for chemical meat. So, despite any decreases in horse manure (methane, carbon dioxide, and hydrogen sulide), as well
fertilizers, improve plant growth, reduce soil erosion and throughout the city streets, mounds of manure were as fertilizer through microbial co-digestion.

nutrient run-off, alleviate soil compaction, and even help (and still are) an unsightly issue at dairy and meat During a multi-stage digestion process, the substrate
the soil retain water.
farms.
provides most of the carbon needed for biomethane
As the saying goes, “What comes around goes
production, while the manure provides pH, alkalinity,

74 nacleanenergy.com
JANUARY/FEBRUARY 2014