Biomass is renewable organic material that comes from plants and animals.

Biomass sources for energy include:

• Wood and wood harvesting and processing residues and wastes—firewood, wood pellets, and wood chips, lumber and furniture mill sawdust and waste, and black liquor from pulp and paper mills
• Agricultural crops, residues and waste materials—corn, soybeans, sugar cane, switchgrass, woody plants, and algae, and crop and food processing residues—mostly to produce biofuels
• Biogenic materials in municipal solid waste—paper, cotton, and wool products, and food, yard, and wood wastes
• Animal manure and human sewage for producing biogas/renewable natural gas

SOURCE: https://www.eia.gov/energyexplained/biomass/