Biomass is organic material derived from plants or animals that can be used to generate energy, including woody materials, agricultural residues, energy crops, and organic waste. While “bioenergy” might suggest a recent invention, the utilization of biomass predates recorded history. Tracing its use reveals a long relationship that began with pure survival and evolved into complex, modern energy systems. Biomass has been a dominant energy source for most of human existence.
The First Uses of Biomass
The initial use of biomass was linked to the discovery and mastery of fire by early hominins. Controlled fire use began as early as 700,000 years ago, representing a transformative technological leap that enabled survival advantages.
The fuel for these first fires was readily available organic material, primarily wood, dried grasses, and animal dung. The heat provided warmth, allowing early humans to inhabit colder climates. Cooking food became possible, providing a more easily digestible energy source that fueled brain development.
Fire also offered protection from predators and led to the creation of more advanced tools through processes like heat-treatment. This foundational use of biomass established combustion as the first and most enduring method of bioenergy conversion.
Biomass in Ancient Societies and Early Industry
As human societies transitioned from nomadic hunter-gatherers to settled communities, biomass use scaled up and became more specialized. Agriculture meant that crop residues, such as straw and husks, were available as fuel alongside wood. This reliance continued for millennia, with biomass remaining the largest source of energy consumption in many regions until the mid-19th century.
The industrial application of biomass began in ancient times, notably with the large-scale production of charcoal. Charcoal is a purer carbon form created by heating wood in a low-oxygen environment. Its higher energy density and cleaner burn made it the fuel of choice for early metallurgy, forging, and pottery production.
During the pre-Industrial Revolution era, wood dominated as the primary global energy source, used extensively for domestic heating, construction, and naval shipbuilding. Early industrial processes like glassmaking and brick firing relied almost entirely on wood and charcoal. Biomass was only displaced by the widespread adoption of coal in the 18th and 19th centuries.
The Modern Revival of Bioenergy
The shift away from fossil fuels in the late 20th century spurred a renewed interest in biomass, transitioning from traditional burning to modern bioenergy systems. The oil crises of the 1970s accelerated research into advanced conversion technologies, highlighting the need for domestic, renewable energy sources. Modern bioenergy now encompasses advanced processes that convert organic materials into heat, electricity, or liquid and gaseous fuels.
Liquid Biofuels
The development of liquid biofuels for the transportation sector became a major focus. Bioethanol, produced through the fermentation of sugars and starches from crops like corn or sugarcane, serves as a renewable substitute for gasoline. Similarly, biodiesel is created by chemically reacting vegetable oils or animal fats with an alcohol, providing an alternative to petroleum diesel. Brazil has leveraged this technology to maintain a large fleet of flexible-fuel vehicles.
Thermal Conversion and Advanced Systems
Beyond liquid fuels, advanced thermal conversion technologies allow for the efficient use of diverse biomass feedstocks, including dedicated energy crops and municipal solid waste. Gasification converts biomass into synthesis gas (syngas), a versatile fuel used to generate electricity or heat. Pyrolysis involves heating biomass without oxygen to produce bio-oil, which can be refined into fuels or chemical feedstocks.
Modern bioenergy systems also include Combined Heat and Power (CHP) plants, which simultaneously produce electricity and useful thermal energy, significantly boosting overall energy efficiency. Technologies like Bioenergy with Carbon Capture and Storage (BECCS) are being explored. BECCS captures carbon dioxide emissions from biomass combustion and stores them underground, potentially creating a carbon-negative energy source. This complex, technology-driven approach distinguishes modern bioenergy from past combustion practices.