Energy crops are specifically grown to produce some form of energy and are considered a type of biomass.  (Biomass is any organic matter which is available on a renewable basis through natural processes or as a by-product of human activity such as agricultural crops and crop residues, wood and wood waste, and municipal solid waste.)  Energy may be generated through direct combustion or gasification of the crops to create electricity, or through the creation of liquid fuels such as ethanol to be used in transportation vehicles.

Energy crops are generally divided into two different types: herbaceous and woody.

Herbaceous Energy Crops
Herbaceous energy crops are mostly types of grasses which are harvested like hay.  Perennial grasses, such as switchgrass, miscanthus, bluestem, elephant grass and wheatgrass have all been found to be good energy crops.  These grasses regrow from their roots and therefore don't require replanting for long periods of time (15 years or more).

Short Rotation Woody Energy Crops
The other type of energy crops are Short Rotation Woody Crops (SRWC). This includes cottonwood, silver maple, black locust, poplar, and willow. During the first two years when the trees are establishing themselves weed control is necessary.  Fertilization is normally applied after the 2nd or 3rd year when the trees can fully utilize the nutrients. From the third year to harvest (4-10 years) the trees require little maintenance.  SRWCs can also be grown for a primary purpose such as paper production and the waste can be utilized for energy.

• ENERGY CROPS and Their Potential Development in Michigan - Kelly Launder, MBEP
• The Economic Impacts of Bioenergy Crop Production on U.S. Agriculture

• U.S. Department of Agriculture
• U.S. Department of Energy-BioPower Program
• Oak Ridge National Laboratory-Bioenergy Feedstock Development Program
• Oak Ridge National Laboratory-Bioenergy Information Network
• Institute for Local Self-Reliance
• New Uses Council