How is biomass is used today?

Biomass provides a surprisingly large amount of the world’s energy – 10% of total global primary energy consumption – but most of that is wood and charcoal gathered and used in the most primitive ways, as shown at right.

More than 2.4 billion people, generally among the world’s poorest, rely directly on wood, crop residues, dung, and other biomass fuels for their heating and cooking needs. In rural sub-Saharan Africa, women carry on average 11 pounds of wood 3 miles every day to meet their household needs for fuel.

Burning this biomass in inefficient stoves or over open flames is in many cases the only way to stay warm or cook a meal – but such stoves are a health and safety hazard. The smoke inhaled while cooking is responsible for more than 1.6 million deaths annually, mostly among women and children.

Bioethanol production and use in Europe

Co-firing

Co-firing involves burning biomass, along with coal, in traditional power plant boilers. This is considered to be one of the most economic ways to produce electricity from biomass, because existing power plant equipment can be used without major modifications. Some coal-fired power plants in North America use this technology to help reduce the use of coal and, thereby, lower emissions of carbon dioxide, sulphur dioxide and nitrogen oxides. Co-firing also allows biomass to be converted to electricity at a higher thermal efficiency in the 33 per cent to 37 per cent range.
Bioethanol production and use in Europe

Gasification

New technologies have been developed to gasify biomass into a useful energy source. These operate by heating solid biomass at high temperatures in an oxygen-deprived environment to produce a fuel gas, which contains between one fifth and one half the heat content of natural gas. This gas can be used to drive highly efficient combined cycle systems to generate electricity. Gasification offers some advantages over direct combustion: for example, gasifying biomass to produce electricity is twice as efficient as burning it directly and results in lower emissions of particulate matter and greenhouse gases. Gasification systems can also be combined with fuel cell systems, which convert hydrogen gas to electricity and heat.

More than half of these deaths occur among children under five years of age. In developing countries with high mortality rates overall, indoor air pollution ranks eighth in terms of the risk factors that contribute to disease and death. Moving away from these dirty uses of biomass is a clear public health priority.