Biofuels
can be divided, based on their state of aggregation, into solid,
liquid, and biogas.
Solid
biofuels can be used for energy purposes in the processes of direct
combustion, gasification, and pyrolysis in the forms of:
-
wood and wood waste (including wood shavings from
fast-growing tree species: willow, poplar)
-
straw and seeds (of corn and rape)
-
straw from plantations of special energetic
plants like Miscanthus, Topinambur etc.
-
sewage sediments
-
waste paper
-
a number of other organic waste produced on
different stages of cultivation and processing of plants (hay, corn,
cane and sugar cane waste, olive husk, roots, fruit processing
waste, etc.).
The
diversity of materials and the need to adjust technology and power
results in biofuels being used in different forms. Wood can be used
in the form of pieces, chips, shavings, sawdust, or compacted
(briquette, pellets). Hay and other biofuels from herbaceous plants
are used in the form of compacted cubes and bales, chaffs, briquette
and pellets.
The global advantages are connected with
diminishing negative environmental impact of the use of fossil fuels
(pollution emissions, waste production, soil and landscape
degeneration). Biofuels also pose a chance for increasing income in
agriculture, forestry, and orcharding and creating jobs in biofules’
production sector.