This week we take a look at the sustainability performance of products over their entire life cycle, from cradle to cradle. After analyzing the large number of products-chemicals we are in daily contact with, we identify the need for LCA, learn about the motivations to conduct LCAs versus other environmental tools. The goals and system definition step defines the goal and scope of the study, including the product function, functional unit, and the product system and its boundaries

The Life Cycle Inventory, the second LCA phase, quantifies the inventory of the various elementary flows of resource extractions and substance emissions crossing the system boundary. We first learn how to build the life cycle inventory and determine aggregated elementary flows from cradle to gate. We then establish the energy and CO2 balance for several products, identifying the dominant stages in the life cycle. This module then provide an overview of existing databases, describes in further detail the widespread ecoinvent database, illustrating the inventory via a simple car example.

The chapter finally introduces us to two special topics of importance: the allocation of emission between co-products and the possibilities offered by Input-output allocation to complement the process LCA approach developed in detail in this chapter.

The life cycle impact assessment (LCIA) is the third phase of an LCA. It use the inventory data to determine their environmental impacts and compare different types of impacts. The impact assessment methods are simple to apply, though their development can be relatively complex. After an introduction to LCIA and various environmental impacts, we first present the LCIA principles and framework. The module then details and illustrates using the Impact World+ method each LCIA step, i.e. a) the classification of emissions into different impact categories, b) the characterization of midpoint impacts, c) the damage (end point) characterization and the optional d) normalization and e) weighting steps. The module finishes by an overview of the existing LCIA methods and the present research efforts to arrive to a global consensus method.

This chapter aims to guide you in the interpretation of results, in the implementation of an LCA in the SIMAPRO software and in the environmental classification of products. After describing the main interpretation principles, we illustrate the interpretation steps using an example of desktop versus laptop computers. We then discuss strategies to check LCA results, and identify and discuss the main uncertainties in life cycle impact assessment results and illustrate it with the hands drying example. We then perform a SIMAPRO tutorial exercise, implementing the hand drying example in SIMAPRO. We finally discuss a simplified product classification and provide rules for sustainable design of products, also looking at reuse,recycling and (e-)waste strategies.