Alfalfa: Bioenergy and More.

Alfalfa (Medicago sativa) has the potential to be a significant contributor to America's renewable energy future.  In an alfalfa biomass energy production system, alfalfa forage would be separated into stem and leave fractions. The stems would be processed to produce energy, and the leaves would be sold to provide additional income as a livestock feed and/or a source of value-added products (e.g., genetically modified to produce specialty proteins, pharmaceuticals, or industrial chemicals). Other value-added components unique to an alfalfa biomass energy production system include a fertilizer N replacement value (for subsequent crops in rotation), increased soil N and C concentrations, and improved ground water quality. Both biochemical [saccharification and fermentation to liquid fuel (ethanol)] and thermochemical (combustion or gasification) conversion technologies can be used to produce energy or electricity from alfalfa biomass. Alfalfa stem cell wall sugar yields and lignin concentration impacted the efficiency of energy conversion. The use of unique biomass-type alfalfas in combination with modified production practices increased potential energy yields from alfalfa biomass. Improved genetic sources, production practices, and conversion efficiencies, along with the advantages of a secondary income and N credits, will enhance alfalfa’s role as a renewable energy crop.