Technology Status - NET Nowak Energie & Technologie AG

transport, emissions, etc.) of fast pyrolysis is that fuel production is separated
from power generation.
Gasification is a form of pyrolysis carried out with more air and at higher
temperatures in order to optimise the gas production. The resulting gas is
more versatile than the original solid biomass. The gas can be burnt to
produce process heat and steam or used in internal combustion engines or
gas turbines to produce electricity. It can even be used as a vehicle fuel.
Biomass gasification is the latest generation of biomass energy conversion
processes and offers advantages over direct burning. In techno-economic
terms, the gas can be used in more efficient combined-cycle power
generation systems, which combine gas turbines and steam turbines to
produce electricity. The conversion process - heat to power - takes place at a
higher temperature than in the steam cycle, making advanced conversion
processes thermodynamically more efficient. In environmental terms, the
biogas can be cleaned and filtered to remove problematic chemical
components.
Anaerobic digestion (AD) is a biological process by which organic wastes are
converted to biogas - usually a mixture of methane (40% to 75%) and carbon
dioxide. The process is based on the breakdown of the organic
macromolecules of biomass by naturally-occurring bacteria. This
bioconversion takes place in the absence of air, thus anaerobic, in digesters,
i.e. sealed containers, offering ideal conditions for the bacteria to ferment
(“digest”) the organic feedstock to produce biogas. The result is biogas and
co-products consisting of an undigested residue (sludge) and various watersoluble
substances. Anaerobic digestion is a well-established technology for
waste treatment. Biogas can be used to generate heat and electricity through
gas, diesel or “dual fuel” engines at capacities of up to 10 MW. About 80% of
industrialised global biogas production stems from commercially exploited
landfills. The methane gas produced at landfills can be extracted from
existing landfills by inserting perforated pipes through which the gas travels
under natural pressure. If not captured, this methane would eventually
escape into the atmosphere as a greenhouse gas. Another common way of
producing biogas by AD is by using animal manure. Manure and water are
stirred and warmed inside an air-tight container (digester). Digesters range in
size from around 1m 3 for a small household unit to as large as 2,000m 3 for a
large commercial installation.
Feedstock
Bioenergy is renewable but there is some argument about what feedstocks
can be considered renewable, for example there is much controversy over
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