Biomass (energy)

See biomass (ecology) for the use of the term in ecology, where it refers to the cumulation of living matter

Switchgrass, a tough plant used in the biofuel industry in the United States

Rice chaff.

Biomass, in the energy production industry, refers to living and recently dead biological material which can be used as fuel or for industrial production. Most commonly, biomass refers to plant matter grown for use as biofuel, but it also includes plant or animal matter used for production of fibres, chemicals or heat. Biomass may also include biodegradable wastes that can be burnt as fuel. It excludes organic material which has been transformed by geological processes into substances such as coal or petroleum. It is usually measured by dry weight.

The term biomass is useful for plants, where some internal structures may not always be considered living tissue, such as the wood (secondary xylem) of a tree. This biomass became produced from plants that convert sunlight into plant material through photosynthesis.

Sources of biomass energy lead to agricultural crop residues, energy plantations, and municipal and industrial wastes.

Biomass is grown from several plants, including miscanthus, switchgrass, hemp, corn, poplar, willow and sugarcane. The particular plant used is usually not very important to the end products, but it does affect the processing of the raw material. Production of biomass is a growing industry as interest in sustainable fuel sources is growing.

Though biomass is a renewable fuel, and is sometimes called a 'carbon neutral' fuel, its use can still contribute to global warming. This happens when the natural carbon equilibrium is disturbed; for example by deforestation or urbanization of green sites. These activities are termed 'carbon leakage'. GO BIOMASS Biomass is part of the carbon cycle. Carbon from the atmosphere is converted into biological matter by photosynthesis. On decay or combustion the carbon goes back into the atmosphere or soil. This happens over a relatively short timescale and plant matter used as a fuel can be constantly replaced by planting for new growth. Therefore a reasonably stable level of atmospheric carbon results from its use as a fuel. It is commonly accepted that the amount of carbon stored in biomass is approximately 50% of the biomass by weight.

Although fossil fuels have their origin in ancient biomass, they are not considered biomass by the generally accepted definition because they contain carbon that has been 'out' of the carbon cycle for a very long time. Their combustion therefore disturbs the carbon dioxide content in the atmosphere.

Other uses of biomass, besides fuel:

• Building materials
• Biodegradable plastics and paper (using cellulose fibres)

Plastics from biomass, like some recently developed to dissolve in seawater, are made the same way as petroleum-based plastics, are actually cheaper to manufacture and meet or exceed most performance standards. But they lack the same water resistance or longevity as conventional plastics.

Biomass production for human use and consumption.

BIOME ECOSYSTEM TYPE	Area	Mean Net Primary Production	World Primary Production	Mean biomass	World biomass	Minimum replacement rate
	(million km²)	(gram dryC/sq metre/year)	(billion tonnes/year)	(kg dryC/sq metre)	(billion tonnes)	(years)
Tropical rain forest	17.0	2,200	37.40	45.00	765.00	20.45
Tropical monsoon forest	7.5	1,600	12.00	35.00	262.50	21.88
Temperate evergreen forest	5.0	1,320	6.60	35.00	175.00	26.52
Temperate deciduous forest	7.0	1,200	8.40	30.00	210.00	25.00
Boreal forest	12.0	800	9.60	20.00	240.00	25.00
Mediterranean open forest	2.8	750	2.10	18.00	50.40	24.00
Woodland and shrubland	5.7	700	3.99	6.00	34.20	8.57
Savanna	15.0	900	13.50	4.00	60.00	4.44
Temperate grassland	9.0	600	5.40	1.60	14.40	2.67
Tundra and alpine	8.0	140	1.12	0.60	4.80	4.29
Desert and semidesert scrub	18.0	90	1.62	0.70	12.60	7.78
Extreme desert, rock, sand or ice sheets	24.0	3	0.07	0.02	0.48	6.67
Cultivated land	14.0	650	9.10	1.00	14.00	1.54
Swamp and marsh	2.0	2,000	4.00	15.00	30.00	7.50
Lakes and streams	2.0	250	0.50	0.02	0.04	0.08
Total continental	149.00	774.51	115.40	12.57	1,873.42	16.23
Open ocean	332.00	125.00	41.50	0.003	1.00	0.02
Upwelling zones	0.40	500.00	0.20	0.020	0.01	0.04
Continental shelf	26.60	360.00	9.58	0.010	0.27	0.03
Algal beds and reefs	0.60	2,500.00	1.50	2.000	1.20	0.80
Estuaries & mangroves	1.40	1,500.00	2.10	1.000	1.40	0.67
Total marine	361.00	152.01	54.88	0.01	3.87	0.07
Grand total	510.00	333.87	170.28	3.68	1,877.29	11.02

Source: Whittaker, R. H. (1975). "The Biosphere and Man". In Leith, H. & Whittaker, R. H. (ed.). Primary Productivity of the Biosphere. Springer-Verlag. pp. 305–328. ISBN 0-3870-7083-4. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: multiple names: editors list (link); Ecological Studies Vol 14 (Berlin)

See also

• Anaerobic digestion
• Biofuel
• Biomass gasification
• Biomass to liquid
• Energy crop
• Thermal mass

External links

• Everything Biomass
• Michigan Biomass Energy Program
• BioMASS Laboratory at University of Illinois at Urbana-Champaign
• Forest Bioenergy
• Texas State Cons. of Energy Office Biomass Article
• Kentucky fc