Bioenergy should not use corn or wheat, study concludes
MONTREAL, Quebec, CA, 2004-08-11 (Refocus Weekly)
The best use of biomass to reduce GHG emissions is the use of switchgrass to ethanol, or the future use of switchgrass to hydrogen.
Wood to combined heat & power is second choice, followed by afforestation,
then corn to ethanol, wood to electricity, wheat to ethanol and then canola to
biodiesel, explains the study ‘Environmentally Preferable Uses of Biomass’
that was prepared for the North American Commission for Environmental
Cooperation. “CHP has good benefits; electricity only does not,” says author
Martin Tampier.
“Ethanol from lignocellulosic biomass may make sense, whereas ethanol from
grains is not recommended,” he adds. “If biomass is specifically grown to
produce energy, avoid using low-yielding energy crops” such as wheat, canola
or corn because they require considerable energy inputs.”
“This brings into question current thinking in both Canada and the U.S., where
corn and wheat are increasingly promoted as ethanol feedstocks.”
Hydrogen produced from biomass may make sense in future, and landfilling of
biomass waste with gas collection may outperform incineration if done well, it
adds. The report identifies environmentally-preferable uses for biomass and
assess the lifecycle GHG emission reductions of selected biomass sources.
Biomass that is harvested sustainably is not considered to create net GHG
emissions because the released CO2 is recaptured by the following crop cycle.
The aim of the analysis was to determine if there were significant differences
in emission reductions from different biomass and land use options.
Based on lifecycle, GHG emissions from growing, collecting and processing
biomass were weighed against the displaced emissions from fossil fuels, with the
results presented on a basis of per-tonne of biomass input and per-hectare of
land used for energy crops.
“Use biomass waste and energy crops where they displace fuels with high carbon
content,” it recommends. “Combined heat and power, or the production of
either ethanol or hydrogen are preferred over electricity-only options.”
“If the ultimate goal is to displace a maximum quantity of fossil fuels, CHP
is the
preferable biomass use option.”
Landfilling and incineration are the best options to minimize GHG emissions from
municipal solid waste, and biodiesel should not be produced from virgin
vegetable oils.
“The initial question was: If a tonne of biomass is available, which use would
deliver the most GHG emission reductions and would therefore be preferred from
an environmental point of view,” the report explains. Biomass was examined as
waste material and as a crop grown specially for use as a feedstock for energy
or fuel production. The 29 threads compared biomass feedstocks for ethanol,
biodiesel, hydrogen, electricity, CHP, landfilling composting, incineration and
carbon sequestration through afforestation.
Click
here for more info...
Visit http://www.sparksdata.co.uk/refocus/ for your international energy focus!!
|