Biomass is a renewable source of energy that consists of organic material that comes from plants and animals. Biomass contains stored energy from the sun and when burned the energy is released as heat. Different kinds of biomass such as corn, wood chips, logs, bark and even garbage is used to produce electricity. The most popular biomass energy is burning of trees for cooking and warmth. The downside is that burning releases carbon dioxide (CO2) into the atmosphere and is a major contributor to unhealthy air in many areas.More modern forms of biomass energy are methane generation and production of alcohol for automobile fuel and fueling electric power plants.