Biomass is all plant and animal matter on the Earth's surface. Harvesting biomass such as crops, trees or dung and using it to generate energy such as heat, electricity or motion, is bioenergy.

Biomass is a very broad term which is used to describe material of recent biological origin that can be used either as a source of energy or for its chemical components. As such, it includes trees, crops, algae and other plants, as well as agricultural and forest residues. It also includes many materials that are considered as wastes by our society including food and drink manufacturing effluents, sludges, manures, industrial (organic) by-products and the organic fraction of household waste.

Biomass can further be divided into more specific terminology, with different terms for different end uses: heating, power (electricity) generation or transportation. We tend to use the term 'bioenergy' for biomass energy systems that produce heat and/or electricity and 'biofuels' for liquid fuels for transportation. Bioenergy can also be used for cooling using absorption chillers that work on the same principle as your refrigeratior.

In many ways biomass can be considered as a form of stored solar energy. The energy of the sun is 'captured' through the process of photosynthesis in growing plants.'