Crops that are grown specifically for energy (electricity or liquid fuels). Examples of plants and trees that are cultivated as energy crops include corn, sugar cane, willow, alfalfa, poplar, switchgrass and eucalyptus.
Crops grown specifically for their fuel value. These include food crops such as corn and sugarcane, and nonfood crops such as poplar trees and switchgrass. Currently, two energy crops are under development: short-rotation woody crops, which are fast-growing hardwood trees harvested in 5 to 8 years, and herbaceous energy crops, such as perennial grasses, which are harvested annually after taking 2 to 3 years to reach full productivity.
A 'carbon neutral' energy source contributing to renewable energy. For example, short rotation coppice or willow plantation uses carbon dioxide to grow plants. Crops may then be burned to create energy - hence carbon neutral.