LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 2C: QUANTIFICATION AND REDUCTION OF UNCERTAINTY 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
188
Assessing the optimum level of detail for secondary GHG emissions
databases
Ricardo Teixeira *
Bluehorse Associates, 12 rue Soyer, 92200 Neuilly-sur-Seine, France
E-mail: ricardo.teixeira@bluehorseassociates.com
ABSTRACT
Life Cycle Assessment (LCA) is a prohibitive initiative for companies with a high number of products because LCA can prove to be
time- and resource-intensive. The LCA process can possibly be rendered less overwhelming for companies by simplifying the datasets
by using “emission factors” instead of inventories. In this paper, we test if simplified data (emission factors measured in kg CO2e
per kg of product) can provide statistically solid results in LCA studies in the agri-food sector. We build a linear statistical model to
cluster agri-food records with similar average CO2e emissions.
Preliminary results show that it is possible to obtain what we call “magic numbers” - statistically significant average CO2e emission
factors for product clusters for certain classes of products. Data clustered in high-level groups (e.g. butter) has high variance; but
lower-level clustering (e.g. butter with herbs and butter without herbs) results in statistically significant “average” emissions.
Keywords: Life Cycle Assessment, database management, simplified LCA, agri-food sector, carbon footprint
1. Introduction
The past years have seen Life Cycle Assessment (LCA) moving away from academic studies and being
implemented into companies’ daily operations such as research and development. Product labelling using
LCA is being implemented on a larger scale. Private initiatives by retailers like Tesco (Clare and Little,
2011) and the French government pilot (ADEME, 2011) are signs of this evolution, which has created the
demand for LCA tools capable of providing results for a large volume of products. Tesco found that complex
methods, or even traditional LCA, may be too time- and resource-intensive, thus the reason they terminated
the initiative to label each product using traditional LCA methods. To overcome this barrier, a more practical,
business-oriented side to LCA is required to simplify without compromising accuracy. Furthermore, for
objectives such as getting in-depth knowledge on the supply chain, estimates based on full LCA methods
may not provide the appropriate level of detail. There is a difference between accuracy (calculating the right
number) and precision (many decimal places).
Given the needs of larger scaled agri-food companies this begs the question: How far simplification can
go in LCA tools? On the tool interface and outputs side, there is virtually no ceiling to how user-friendly
tools that can be built. On the methodological side, the debate is on-going. On the database side, however,
there is an understanding that precision is needed - data must be specific and primary. The recurring fear of
“garbage in, garbage out” has overshot the quality standards for primary data. ISO 14040 (ISO 1997) recommends
the use of emissions-base unit processes so that every record in the database is a life cycle with
traceable inputs and outputs. ISO-compliant tools, commonly known as “full LCA” tools, dominate the market
while using this principle. A survey done on LCA practitioners in the agri-food sector last year revealed
that the most commonly used tools are still “full LCA” tools such as SimaPro by PRe Consultants and Gabi
by PE International (Cooper and Fava, 2006; Teixeira and Pax, 2011).
Lately, the makers of simplified tools have been trying to educate the market on another approach. One of
the strategies used is referring to built-in databases with emissions for pre-recorded life cycles (Weitz et al.,
1996; Graedel, 1998). Instead of giving users the possibility of rebuilding a life cycle for a product (e.g, butter
– see below for more on this example), the database comprises pre-established life cycle impact assessment
(LCIA) results. Users choose the most appropriate one for their case (e.g, choose between CO2e emissions
for conventionally produced simple butter in the Netherlands and for organic herb butter in Switzerland).
Graedel (1998, cit. in Lifset, 2006) argued that simplified LCA can provide around 80% of the findings
from full LCA. To this day, however, a study is needed to justify the impact of simplified procedures in final
LCA results and confirm or refute Graedel (1998). A true test cannot consist of running an LCA for one
product using both simplified and full LCA procedures because this is always case specific and no general
conclusions can be drawn. In particular cases great differences may occur, but what matters is if on average,
for a large number of LCAs, the simplified methodology yields high variability or an inherent bias on results;
therefore an alternative method must be found.
In this paper we propose an alternative approach to test the hypothesis that simplified data can still provide
accurate, statistically solid results in LCA studies.