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126 Biofuels for a More Sustainable Future

The Inventory Analysis phase of LCA is concerned with the collection of
technical data, such as the mass and energy flows throughout the system’s
life cycle, and the estimation of flows to, and from, the environment. Typ-
ically this is achieved with some reliance on existing databases or literature to
provide data for background systems (e.g., data on the environmental bur-
dens associated with material inputs). In Europe, for instance, the Swiss non-
profit “Ecoinvent” database (Ecoinvent, 2018) is the most widely used and
accepted life cycle inventory database. Many other similar databases exist,
such as the US LCI Database managed by NREL (National Renewable
Energy Laboratory, 2012).
The third phase of LCA, Impact Assessment, uses environmental impact
coefficients, often referred to as characterization factors, to estimate the
potential environmental impacts caused by the burdens identified during
the Inventory Analysis phase. These impacts are calculated as follows:
X
E k ¼ e k, j B j
where
E k ¼ Total environmental impact k
e k,j ¼ Environmental impact coefficient describing the contribution of
substance j to impact k
B j ¼ Environmental burden of substance j contributing to the impact k
The impact categories included in an LCA act as useful environmental
indicators for potential adoption in LCSA. However, the exact list of indi-
cators generated by an LCA depends on the impact assessment method
adopted and a variety of options exists. Much of the existing literature
has used the CML method (Guin ee et al., 2002) but there is increasing con-
sensus that this is now outdated. Alternatives include IMPACT2002+
( Jolliet et al., 2003), TRACI (Bare, 2002; Bare, 2011), ILCD (Wolf
et al., 2012), and ReCiPe (Goedkoop et al., 2012; Huijbregts et al.,
2016). Of these options, ReCiPe is often seen as the state of the art and there
is some evidence to suggest that it is the most widely used method, although
a plurality is evident in the community (Prox, 2018). Table 5.2 lists the LCA
impact categories in the CML, ILCD, and ReCiPe methods.
In all cases, the characterization factors used to account for global warm-
ing/climate change are derived from the reports of the Intergovernmental
Panel on Climate Change (e.g., IPCC, 2014). It should be noted that this
indicator presents specific challenges when applied to systems with biolog-
ical components, such as the food or bioenergy sectors, due to the need to