Biomass refers to renewable organic matter derived from plants and animals, containing stored chemical energy from the sun, generated through photosynthesis. It can be directly combusted for heat or transformed into liquid and gaseous fuels through various processes.
Until the mid-1800s, biomass constituted the primary source of annual energy consumption in the United States. By 2022, it accounted for almost 5% of the nation’s total primary energy consumption. Biomass finds applications in heating, electricity generation, and as a transportation fuel, playing a vital role in various countries, particularly in cooking and heating within developing nations.
What are the Sources of Biomass?
Notable biomass sources for energy production encompass:
- Wood and wood processing residues such as firewood, wood pellets, wood chips, as well as sawdust and waste from lumber and furniture mills, alongside black liquor sourced from pulp and paper mills.
- Agricultural crops and waste materials, including corn, soybeans, sugar cane, switchgrass, woody plants, algae, and residues from crop and food processing, primarily utilized for biofuel production.
- Biogenic materials within municipal solid waste, involving paper products, cotton and wool items, and waste from food, yard, and wood, serving as potential biomass resources.
- Utilization of animal manure and human sewage for the production of biogas, known as renewable natural gas.
Also See: What are E-fuels?
How is Biomass Converted into Energy Through Various Processes?
Biomass can be converted to energy through various methods, including:
1. Direct Combustion: This involves the direct burning of biomass to produce heat for various applications such as heating buildings, providing industrial process heat, and generating electricity in steam turbines.
2. Thermochemical Conversion: Through processes like pyrolysis and gasification, biomass is heated at high temperatures with limited oxygen to yield various valuable products:
- Pyrolysis results in the production of bio-oil, renewable diesel, methane, and hydrogen.
- Hydrotreating is used to process bio-oil into renewable diesel, gasoline, and jet fuel.
- Gasification generates synthesis gas (syngas), which can be used for electricity generation, heating, and as a source of hydrogen or for the production of liquid fuels through the Fischer-Tropsch process.
3. Chemical Conversion (Transesterification): This process is utilized to convert vegetable oils, animal fats, and greases into biodiesel.
4. Biological Conversion: Through fermentation and anaerobic digestion, biomass can be transformed into:
- Ethanol is commonly used as a vehicle fuel.
- Biogas (or biomethane) is produced in anaerobic digesters. It can serve as a renewable natural gas for various applications, comparable to traditional fossil fuel natural gas.
Continual research and development efforts are focused on improving these conversion methods and exploring new pathways to make biomass a more effective and efficient source of energy.
Must Read: What is Biodiesel?