Environmental Engineering Reference
In-Depth Information
Defining boundaries
In the case of food production, the life cycle of the product depends on many successive
stages that involve the agricultural phase, the industrial processing phase, retail and
distribution, and consumption in the household. So the question is where the boundaries
should be set; and the answer is it depends. A food processor main goal is to introduce
improvements in the facility to decrease the environmental burden of the operation; therefore,
the boundaries will encompass just the processing plant, including administrative and
auxiliary buildings. If transportation of finished product to a distribution center is also
considered part of the burden, then transportation should be included in the analysis. On the
other hand, if, for instance, the purpose is to make environmental claims about the product,
then production of raw materials and consumption should be included in the analysis. An
illustrative example on boundary setting is the analysis of the total carbon footprint of Fat Tire
Amber
®
Ale by the New Belgium Brewing Company. In the report's executive summary, the
first paragraph describes the boundaries as: “System boundaries of the assessed life cycle
encompass acquisition and transport of raw materials, brewing operations, business travel,
employee commuting, transport and storage during distribution and retail, use and disposal of
waste” (New Belgium Brewing Company, 2008).
Selecting metrics
Establishing metrics are essential for any efficiency improvement. Sustainability metrics
are the indicators that will show whether or not companies are moving in the right direction,
and if so, how much progress is being made. Examples of metrics are material intensity,
energy intensity, carbon emissions, and water consumption. Impact categories of the LCA
can also be used to monitor progress. Single-score metrics for the LCA exist, but they are
still controversial so their use is not recommended. Chapter 4 discussed indicators and
metrics more fully.
Assessing the current situation
Once the metrics are selected, the next step is to evaluate the present situation by applying
the metrics within the boundaries of the system in analysis. For the purpose of this discus-
sion and continuing with the beer production example, let's assume that the interest is
improving the efficiency of the brewery in terms of energy and water consumption. In this
case, the boundaries will include the manufacturing facility and exclude production of raw
materials, transportation, distribution, and consumption.
The next step is the collection of data for electricity, fuel, water consumption, and express
them in terms of a functional unit (e.g., 1 liter of beer). Table 5.2 presents the average energy
and water consumption per liter of beer packed in kegs for a lager beer produced in a small
brewery in northeast Italy. This data can be used as a starting point and as a benchmark after
introducing improvements.
Ranking processes according to impacts
Visualization of data in Table 5.2 and identification of the most important steps in terms
of energy consumption are relatively simple because there are only five processes.
However, if a large number of steps are in place, the identification of the ones that need
immediate attention require the use of some type of tool, for instance a Pareto diagram,
