Biomass is solar energy stored in organic matter in trees, agricultural crops and other living plant material. As trees and plants grow, the process of photosynthesis uses energy from the sun to convert carbon dioxide into carbohydrates (sugars, starches and cellulose). Carbohydrates are the organic compounds that make up biomass. When plants die, the process of decay releases the energy stored in carbohydrates and discharges carbon dioxide back into the atmosphere.

Biomass is a renewable energy source because the growth of new plants and trees replenishes the supply. Living plant material is the source of all biomass fuel. Some biomass fuel resources are waste products left over after plant materials have been used for other purposes or consumed by animals. Other biomass resources are plant materials directly harvested for their energy value. Biomass fuels are readily available throughout the world. Over millions of years, natural processes in the earth transformed organic matter into today's fossil fuels: oil, natural gas and coal. Fossil fuels are not renewable. The oil, natural gas and coal we use today are gone forever.

The use of biomass for energy causes no net increase in carbon dioxide emissions to the atmosphere. As trees and plants grow, they remove carbon from the atmosphere through photosynthesis. If the amount of new biomass growth balances the biomass used for energy, bio energy is carbon dioxide "neutral." That is, the use of biomass for energy does not increase carbon dioxide emissions and does not contribute to the risk of global climate change. In addition, using biomass to produce energy is often a way to dispose of waste materials that otherwise would create environmental risks.

Electricity generation from renewables represents about 3% of all electricity generation in India. India produces a huge quantity of biomass material in its agricultural, agro-industrial, and forestry operations. According to some estimates, over 500 million tons of agricultural and agro-industrial residues alone are generated every year. This quantity, in terms of heat content, is equivalent to about 175 million tons of oil. A portion of these materials is used for fodder and fuel in the rural economy. However, studies have indicated that at least 150-200 million tons of this biomass material does not find much productive use, and can be made available for alternative uses at an economical cost. These materials include a variety of husks and straws. This quantity of biomass is sufficient to generate 15000-25 000 MW of electrical power at typically prevalent plant load factors. In addition, electricity can also be generated from biomass grown on wastelands, road and rail trackside plantations, etc. The quantum of electricity that can be produced from such biomass has been estimated to be in excess of 70 000 MW. Thus, the total electricity generation potential from biomass could reach a figure of about 100 000 MW.