Page 26 - Materials Chemistry, Second Edition

ENVIRONMENTAL LIFE CYCLE ASSESSMENT 7

the policy choice at hand, the technical relations as covered in LCA should be
part of the analysis, but also the broader behavioral mechanisms should be
covered. If all mechanisms together come out negative, showing a rebound,
simple LCA would have given the wrong advice.
A first step for the analysis is to place the choice in a framework of totals
for society. Input-output analysis with environmental extensions can be set up
in an LCA-type manner, with some details added to better cover the choice at
hand. This hybrid analysis has come up as a theoretical tool, with one applica-
tion related to the option of using fuel cell buses in urban transport, see Cantono
et ah (2008). In the old Life Cycle Analysis of cost, the same link to input-output
analysis was pointed out previously, see Staubus (1971). This IO framework
allows one to specify one first secondary effect, the income effect. The higher
cost of fuel cell buses replacing Diesel buses implies lower spending on other
items, with lower environmental impacts there. However, this IO-analysis is
static and cannot cover well broader causal mechanisms. Causal analysis can
only be specified in time. It is the before-after analysis, of the situations with-and-
without specific alternative policies. So the second step involves a dynamic anal-
ysis, of all mechanisms leading to the overall, the macro level, consequences.
The conclusion is that for supporting policy choices with macro level con-
sequences the arbitrary functional unit based LCA will often be too narrow to
give valid answers. A broader framework for analysis is then required.

1.7 Example Biofuels

In the biofuels discussion, all levels of questions come up. They range from
small-step improvement options for a given biotechnology to produce biofu-
els; to the comparison between different fuels, including biofuels; and to an
evaluation of a global shift towards a more biobased energy system. When
looking at a small system, one may assume the changes to be so small that
indirect effects are negligible. But the sum of all these small changes adds up
to a substantial change. A small change in biomass demand for energy will
have a small effect on biomass production and a small effect on energy prices.
However, such effects are additive, and often non-linearly increasing. If biofuel
is relevant, it has to be produced in substantial amounts. This also holds for the
minor improvement in biotechnology. So, indirect effects cannot be ignored.
A next option for simplified analysis is the assumption that all mechanisms
not covered remain equal or do not influence the outcome. Both assumptions
generally are not true in the case of bio-energy, see the OECD (Organization for
Economic Cooperation and Development) study by Doornbosch and Steenblik
(2008). These should be investigated empirically. A final option is to make
assumptions on the rest of the world. One may assume, for example, that all
additional biomass will come from barren lands not fit for food producing
agriculture. This assumption is often present in studies on second and third
generation biofuels. However, the use of fertile grounds will mostly be cheaper
than barren grounds to produce biomass - that is why they were barren. In