By: TANJA SREBOTNJAK, Director of the Hixon Center
The previous two segments of this series covered the history and technical details of determining material criticality. This third and final segment identifies some links between critical raw materials (CRM) and life cycle assessment (LCA).
As you might know, LCA is concerned with quantifying the environmental burden of products from “cradle to grave,” i.e., from the sourcing of the raw materials needed to make a product through manufacturing, use and final disposal or recycling/reuse. Using physical data on the materials and energy used, as well as the environmental emissions and waste generated throughout the “life cycle” of the product, it is possible to estimate the potential environmental impacts attributed to the product, such as its contribution to climate change, ozone layer depletion, and aquatic toxicity.
So how does knowing whether a material is critical help with LCA and vice versa, how can LCA help with assessing material criticality?
The answer to the first question is that LCA can be used to identify so-called hotspots in product life cycles, i.e., the processes and life cycle phases that may cause the most environmental damage. One typical LCA impact category considered is natural resource use and depletion. Since critical materials are often scarce in nature, widely dispersed such that their mining is energy and/or capital intensive, or are produced as a by-product of other raw commodity mining and hence linked to their environmental impacts, it can be a helpful pre-screening step in an LCA to ask if any raw materials going into the product’s life cycle are considered critical. If so, product designers and supply chain managers can look for alternative designs that do not require the material or that can work with substitutes, and thereby reduce the product’s natural resource use and depletion footprint while at the same time reducing the product’s vulnerability to supply shocks associated with the critical material.
In addition, some critical materials experts advocate considering the environmental and social aspects of their production in the process of determining if a material is critical (see reference below). The purpose of such an expansion of the CRM definition would inform critical material users of the wider sustainability implications of critical materials use and associated risks. Using this expanded information in an LCA context could add useful information to life cycle inventory tables and hence provide a more comprehensive assessment of the product’s environmental impacts.
With regard to the second question, i.e., what does LCA have to offer critical materials evaluation; there are several aspects to consider. First, and relating to the previous paragraph, if critical material analysts wish to take environmental impact information into account, they can consult LCA databases to estimate the environmental resource requirements and releases into the environment for the amount of the material consumed by a given product or in a specific sector during a given period time. Second, LCA can help shed light on the “importance in use” aspect of material criticality. Such importance relates to both the prevalence of use of a material in an economy (e.g., some quantity of the material is required by many sectors) as well as the substitutability of the material (e.g., even if only a few sectors require the material, they may depend on it heavily due to its unique properties). Life cycle assessments of key products across the range of sectors using the material can help identify where and how the material is used and if it is technically and economically feasible to replace it with alternatives. Such activities are currently underway in the European Union, which faces a growing demand for several critical materials for some of its green and advanced technology sectors (electric vehicles, solar PV, and consumer electronics) while having only limited EU-internal production. Policymakers have recognized that, in addition to securing the supply chain for these materials, it is beneficial to invest in domestic materials science research and recycling systems to reduce the demand for virgin critical materials.
Recycling is the third link between critical materials and LCA. As a cradle-to-grave modeling tool, LCA can help identify opportunities for collecting, reusing and recycling critical materials such as through “urban mining,” a growing field of research and practice that scavenges the underutilized and discarded items of cities for resources of high value. Scavenging in this context means using highly advanced information, collection and separation technologies to reclaim even small amounts of valuable resources such as critical materials from cars, computers, cell phones, and other items. LCA (often in conjunction with material flow analysis) helps to identify which product components contain most of a valuable material and track them through their life cycle.
Thus, in conclusion, critical materials and LCA are intrinsically linked through the growing need to use natural resources wisely and efficiently. If you are interested in learning more about both, I highly recommend the case study of the Fairphone (https://www.fairphone.com/en/), a phone designed with durability, sustainable material use, fair labor conditions, and reuse/recycling in mind. While still not perfect, the phone shows that green design, functionality, and aesthetics can work together and be economically viable.
If you would like to read more about critical materials determination involving environmental impacts, see Graedel et al., Environmental Science and Technology, 2012. As always, you can reach the Hixon Center with questions and comments at email@example.com.