Life cycle assessment (LCA) is a tool to undertake a systematic environmental assessment of product supply chains. It aims to reveal and quantify environmental impacts and resource use along the complete supply chain of a product or service, that is, from the mining and extraction of its raw materials, to the manufacturing, distribution and use of products, right on to the end of life (e.g. recycling or landfill).
Raw materials and emissions are not only considered for the product under study, but also for all the other materials used in the life cycle of the product. An LCA study encompasses a product carbon footprint and water footprint, but also looks more broadly at the full suite of potential environmental impacts that a product or service may give rise to, for example, damage to human health, damage to eco-system quality and resource depletion. An LCA is thus a complex and data intensive undertaking, but is essential in that it:
- Improves entire systems and not just single parts of systems;
- Avoids decisions that fix one problem but cause another unexpected environmental problem;
- Creates awareness that decisions are not isolated, but that they influence a larger system; and
- Promotes decision-making for the longer term, by considering all environmental issues associated with the decision choice.
The Green House consultants have demonstrated experience in conducting LCA studies in the South African context. We are uniquely positioned with strong research backgrounds in LCA methodology development and recent project experience in conducting LCA studies.
This experience means we are able guide clients towards good problem structuring (scoping), correctly defining the tricky aspects of system definition (e.g. including recycling and multi-function products), and designing an effective data collection strategy.
The crux of an LCA study is the quality of the data that underpins it. We use our extensive proprietary life cycle inventory database (based on adapting the comprehensive ecoinvent database) for screening and background data, whilst our process engineering background assists in factory-specific data collection.
How to do LCA?
Life cycle assessment is governed by an SANS standard1. This standard provides guidelines for the LCA process, but many methodological, modelling and data choices need to be taken when defining the scope of the study.
The first task of an LCA study is typically to draw the system flow chart (see figure for an example). All raw materials and emissions (inputs and outputs) are considered for each of the processes that make up the life cycle of the product. Inputs include the use of resources, such as land and water, as well as material inputs, such as fuels, chemicals etc. Outputs are the emissions to air, water and land associated with the system, as well as all products and by-products. Taken together these processes make up the life cycle system to be analysed, as defined by the system boundary.
The individual inputs and outputs from all processes making up the system are summed together to compile the life cycle inventory (LCI) – a list of all raw materials entering the system and final emissions leaving the system, given per relevant unit of product produced.
The LCI forms the basis of life cycle impact assessment (LCIA). In this next phase of LCA, all the inputs and outputs are grouped into environmental impacts or areas of environmental concern, for example, climate change, acidification, eutrophication, summer smog etc.
LCA is by its very nature data intensive. It is common to use a mixture of primary (site or factory-specific) data and secondary data (LCI databases). The greater the contribution of the former, the more expensive and time-consuming the study is, but the more representative the results.
Reduced scope LCAs can be conducted for short turnaround projects that are resourced with limited budgets. Carbon footprinting is an example of a reduced scope LCA in that the only impact category that is looked at is the effect of greenhouse gases on global warming potential.
A key element of LCA is its aim to avoid shifting problems from one life cycle stage to another, from one geographic region to another and from one environmental medium (air, water or soil) to another. In order to avoid burden shifting, LCA needs to take a broad view of potential environmental impacts, so when a reduced scope LCA is conducted, consultation with an experienced LCA practitioner is crucial to ensure that the limitations are recorded, and to ensure that the scope reduction does not result in overlooking potentially significant impacts. The following options for scope reduction are possible
- Exclusion of life cycle stages from the system boundaries (e.g. the use phase of a product may be neglected)
- Exclusion of inventory items and impact categories (e.g. carbon footprinting, focus on GHG emissions to determine contribution to global warming)
- Screening LCA where data are exclusively obtained from literature and databases (e.g. no process specific data is used in the LCA)
- Qualitative life cycle assessment
It is important to note that LCA predicts potential environmental impacts or damages, as the necessarily global nature of the predictive LCIA models means that they do not take the specific receiving environment into account. Life cycle inventory data (the basis for impact assessment) span multiple geographical locations across countries and even continents in today’s global supply chains, thus LCIA predictive models are not like environmental impact assessment (EIA) models that accurately characterise the actual risks associated with emissions at a particular location. LCIA models must be able to be implemented over widely ranging receiving environments, resulting in an inevitable loss of accuracy at the cost of flexibility and simplicity. This limitation is less significant for global and regional-scale impacts, such as global warming, ozone depletion, acidification, smog formation etc., but it can be very significant for local-scale impacts, such as toxicity damage to ecosystems. Furthermore, LCA does not consider the work environment, e.g. health and safety aspects etc., nor does it typically address social or animal welfare issues (although social LCA is an emerging method).
1 the SANS standard is drawn from the ISO standards, ISO 14040:2006 Environmental management — Life cycle assessment — Requirements and guidelines, International Organisation for Standardization, Geneva, Switzerland; ISO 14040:2006 Environmental management — Life cycle assessment — Principles and framework, International Organisation for Standardization, Geneva, Switzerland.
Why do LCA?
The primary purpose of LCA is to steer decision-makers towards more sustainable products and services, but LCA results are used in a variety of marketing, design and operational contexts:
- LCA results are used to communicate the environmental performance of products, processes or services (i.e. it is a popular tool in marketing).
- LCA is an important tool for the standardised communication of environmental information between customers and suppliers, for example EPDs (Environmental Product Declarations).
- Comparative LCA is used to determine the relative environmental performances of competing products or services, e.g. a paper book vs. an iPad.
- Within a specific company, LCA results may be applied in benchmarking against competitors, or to create greater awareness with clients or shareholders around a product’s environmental performance.
- LCA results may be used to identify risks and opportunities in the product value chain (e.g. across suppliers, retailers and distributors).
- LCA is used in the improvement of products and manufacturing processes, by identifying the points in the value chain with the greatest scope for improvement (such as energy and resource efficiency improvements, substitutions in suppliers/materials, and reductions in emissions and waste generation).
- Screening LCA is a popular tool for eco-design and in product development, where LCA results are used to identify environmental hot spots and to determine the origins of environmentally unfavourable performance, preferably at the design stage, where amendments can still easily be made.
Very often the greatest value of an LCA study lies not so much with the final numbers, but with the exploration of the system and the consequent in-depth understanding of the potential environmental issues that results. It is seldom that one system or decision option performs better than another in all aspects of environmental impact, thus the value of an LCA study often lies with the exploration of the trade-offs between the different environmental impacts of competing options. To reach a conclusion in such instances requires advance decision-support tools, such as those applied in Multi-criteria Decision Analysis.
Environmental product declarations
Environmental product declarations (EPDs) are a standardised application of life cycle assessment, which are undertaken according to the ISO 14025 standard. The purpose of an EPD is to communicate quantified environmental data for a product according to pre-set list of rules specific to that product category. The approach ensures that there is consistency and transparency of information that allows for the direct comparison of products.