INL Researchers Evaluate Alfalfa's Potential as Biofuel

In 2006, Idaho was devastated by the pale cyst nematode, a rare potato pest. While the pest problem was solved, bromide, a component of a highly toxic pesticide sprayed on farmlands, remains on the soil and some of the crops grown in it, including alfalfa grown for cattle feed. The extent of contamination was not realized until pesticide treatments stopped in 2014 after a farmer noticed side effects in cattle fed with crops grown in the treated soil.

Employees at Idaho National Laboratories Biomass Feedstock National User Facility have studied how farmers can benefit from contaminated alfalfa as a combustible fuel. The team transformed bales of alfalfa into pellets or cubes that can be used as fuel in coal-fueled plants. The INL team then monitored the air to determine if bromide was released at any point when alfalfa is processed into fuel.

Researchers found bromide was only released during an emergency procedure in the pellet-forming process. Burning the produced fuel also yielded no bromide to the air. It stayed in the ash, which can then be used to produce cement.

Although alfalfa can burn as a fuel, there's still work to be done as alfalfa fuel tends to "foul" burning chambers, leaving a material not unlike creosote caked in a home chimney.