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Climate change responses: carbon offsets, biofuels and the life cycle assessment contribution

the default (fossil fuel) scenario should be considered in addition to the credits due to fuel sub- 133
stitution. Hence, some authors argue that the use of biomass waste or residue in power produc-
tion should be credited with the savings in emissions associated with the normal route of
biomass disposal in addition to the savings due to forgone fossil fuel combustion (Mann and
Spath 2001). This may add credit to the use of waste biomass, since typical biomass disposal
often contributes to methane emissions.
Lastly, it has been argued (Reijnders and Huijbregts 2003) that because forests sequester
carbon dioxide irrespective of whether it is biogenic or fossil fuel-derived, the carbon contri-
bution of biomass burnt for electricity generation should be counted as if it was fossil fuel-
derived. Accordingly, as 14% of worldwide carbon dioxide emissions are currently sequestered,
14% of biomass burnt should be considered as sequestered, while the remaining 86% should be
counted in overall emissions because burning biomass directly contributes to an increase in
atmospheric carbon dioxide.
Across this range of approaches and options for greenhouse emission abatement, the
approach outlined in the methods chapter (see Chapter 2) regarding consequential LCA
analysis provides a clear framework for assessing the change in systems resulting from specific
decisions. These decisions may be in the product or process selection, or financial investment
in the form of carbon trading, and thus lead to environmentally beneficial changes in practice
being accelerated through the economy. If an LCA timeframe is chosen, at least 500 years or
more, any short-term issues surrounding land use equilibrium, or building product use and
disposal are resolved.

10.3.2 Biomass carbon assessment tools
Given the varying complexity, the methodological challenges and the high level of interest in
biomass energy technologies and bio-sequestration, it is not surprising that several methodol-
ogies and tools have been developed for evaluating the greenhouse gas balances and cost-effec-
tiveness of various biomass energy technologies. There is no standard tool, and typically each
is proprietary, complex and/or restricted to one biomass energy technology or country. This
makes it difficult to compare data on greenhouse gas balances and cost-effectiveness of differ-
ent biomass energy technologies. In Australia, a major biofuels study was undertaken (Beer et
al. 2002) that established a standard framework for comparison of reference biofuels, although
it did not lead to a software tool. One software tool developed in Europe enables user groups to
compute and compare carbon benefits of biomass energy technologies throughout the EU.
This was developed through the EU-funded BIOMITRE project. This study identified about
900 potential technology combinations for biomass energy projects in the European Union
and established a standard method for conducting both biomass and reference system calcula-
tions (Horne 2005). Similarly the Greenhouse gases, Regulated Emissions, and Energy use in
Transportation (GREET) model in the United States of America (USA) provides automated
life cycle calculations for biomass and other fuel options (Argonne 2008).
However, tools have not delivered a high uptake, probably due in part to the complexities
and resultant variations in goal, scope and system boundaries. One review study of biomass
energy technologies for ethanol production found that, of two detailed LCA studies, one is
generally unfavourable, while the other is significantly favourable (Blottnitz and Curran 2007).
This study drew on 47 published LCAs that compared bio-ethanol systems with conventional
fuels, and it concluded that choices about process residue handling and fuel combustion are
important in explaining differences in results. These LCAs typically indicated that reductions
in resource use and global warming can be achieved, although impacts on acidification, human
toxicity and ecological toxicity, occurring mainly during the growing and processing of
biomass, were more often unfavourable than favourable. This indicates one of the dangers of

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