Biomass is a term for organic matter derived from living, or recently living organisms. It is used as a source of energy in both commercial and domestic environments. The term biomass often refers to plants or plant-based materials which are not used for food or feed, such as wood, algae or bamboo.
Biomass application: energy, such as heating, electricity generation, and transport fuels and biobased material, such as biofertilizers, bioplastics and other materials. Increasing the use of biomass can help diversify Europe’s energy supply, create growth and jobs, and lower GHG. Biomass production involves a chain of activities ranging from the growing of feedstock to final energy conversion. Each step along the way can pose different sustainability challenges that need to be managed.
The EC has issued non-binding recommendations on sustainability criteria for biomass that apply to energy installations of at least 1MW thermal heat or electrical power. They:
- forbid the use of biomass from land converted from forest, and other high carbon stock areas, as well as highly biodiverse areas
- ensure that biofuels emit at least 35% less greenhouse gases over their lifecycle (cultivation, processing, transport, etc.) when compared to fossil fuels. For new installations this amount rises to 50% in 2017 and 60% in 2018
- favour national biofuels support schemes for highly efficient installations
- encourage the monitoring of the origin of all biomass consumed in the EU to ensure their sustainability. (Source: EC, access on https://ec.europa.eu/energy/en/topics/renewable-energy/biomass)
Biomass—a source of energy
The biomass is generally understood to exclude coal, oil, and other fossilized remnants of organisms, as well as soils. Biomass encompasses all living things. In the context of biomass energy,the term refers to crops, residues, and other biological materials that can be used as a substitute for fossil fuels in the production of energy and other products.
Biomass fuels store energy from the sun through photosynthesis, ready to be released as heat energy in the process of combustion or broken down into different energy containing compounds. As biomass is growing, Chlorophyll absorbs both water and carbon dioxide from the environment to create oxygen and energy and because of this, the fuel is argued to be carbon neutral. This is because burning biomass is simply returning the previously absorbed carbon back into the atmosphere and not adding to it in the way that fossil fuels do. As a renewable carbon based material, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel, biopolymer or other bioproducts like biocosmetics and biofertilizers. The international community supports the valorisation of residual biomass sources, including biowaste, sludges and agro-forestry residues as sustainable renewable material to be upgraded into high value products or bioenergy towards a sustainable bioeconomy sector development.
Plant biomass composition
The chemical composition of plant biomass varies among species. Yet, in general terms, plants are made of approximately 25% lignin and 75% carbohydrates or sugars. The carbohydrate fraction consists of many sugar molecules linked together in long chains or polymers. Two categories are distinguished: cellulose and hemi-cellulose. The lignin fraction consists of non-sugar type molecules that act as a glue holding together the cellulose fibers.
Typical values for the composition of straw, softwoods and hardwoods:
The table below shows possible ranges in moisture content for selected biomass resources.
|Industrial fresh wood chips and sawdust
|40-60 wt. % (wb)
|Industrial dry wood chips and sawdust
|10-20 wt. % (wb)
|Fresh forest wood chips
|40-60 wt. % (wb)
|Chips from wood stored and air-dried several months
|30-40 wt. % (wb)
|10-30 wt. % (wb)
|15 wt. % (wb)
Some typical characteristics of biomass fuels compared to oil and coal.
Databases on biomass characteristics
Detailed information on energy and chemical characteristics for a wide range of biomass fuels can be found in the following databases:
- IEA Task 32 biomass database www.ieabcc.nl
- Phyllis biomass database www.ecn.nl/phyllis/
- University of technology of Vienna biomass database www.vt.tuwien.ac.at/biobib
In the framework of the IEA Bio-energy task 29, the following educational website was developed http://www.task29.net/