Life Cycle Analysis ( LCA ) - Influence of Life Cycle Analysis on Product and Process Design

Topics Covered

Background

Inputs

Quantifying Inputs

Life Cycle Analysis

A Simplified Model

A More Complex Model

Life Cycle Analysis and Resource Processing

Case Study – Copper Metal Production

What Can be Learnt from Life Cycle Analysis

Using Life Cycle Analysis to Look at the Bigger Picture

Extended Product Responsibility

Life Cycle Analysis and the Built Environment

Life Cycle Analysis and Building Design

Summary

Background

In our modem society, all products and services are based on the use of energy and material resources. While the products and services of stone-age hunter-gatherers or a primitive village economy may have been only one step removed from the natural world and made using only human muscle power and fire, the modern industrial economy relies on a web of diverse material and energy inputs, so complex that even a simple product draws on many different areas of the economy. This web of material and energy inputs can be pictured as a product “root system” drawing materials and energy from the economy. Tim Grant, Program Manager, Life Cycle Assessment, at RMIT’s Centre for Design in Melbourne, refers to it as “the world behind the product.”

Inputs

The world behind the product is more complicated than you might think. Analysing the inputs to a pencil, for example, might produce a highly complex root system looking something like the diagram shown in figure 1, but covering an entire page or more.

Figure 1. An example of an input analysis.

Quantifying Inputs

Quantifying all of these resource inputs requires the collection of a mass of detailed data from many different sources. If this is what is required to calculate the resources and energy embodied in something as simple as a new pencil, just imagine the complexity of the same type of database for a complex manufactured structure like a car, house, or commercial building, for example.

Life Cycle Analysis

To design more sustainable patterns of resource use, we need an appreciation of how economic activities interact with people and the environment. Life Cycle Assessment (LCA) is about measuring the effect on the biosphere, of changes in the “technosphere” (the realm of human activity). It is about measuring the flows of resources through selected pathways in the economy to map the impacts of particular activities on the natural resource base.

A Simplified Model

For many enterprises (e.g. product manufacturers), LCA is, at the present point in time, essentially the same as measuring the embodied material resources and energy of a product as it leaves the factory or foundry. For this type of “cradle-to-gate” application, a simple linear concept of the product system is often used.

Figure 2. The linear concept of the product system.

A More Complex Model

For a more sophisticated concept, however, we need to portray “industrial metabolism” with its loops and feedbacks as shown in the diagram on the next page.

Figure 3. The product life cycle.

Life Cycle Analysis and Resource Processing

Resource processing represents a particularly critical stage in a product life cycle for potential release of gaseous, liquid and solid emissions to the environment. In this stage, chemical transformations take place to extract metals, generate power, and produce industrial materials. Within our organisation, CSIRO Minerals has carried out a series of “cradle-to-gate” LCAs (from ore extraction to refined metal) on primary metal production processes. These studies will help identify “hot spots” in production chains with regard to environmental impacts, and assist in re-designing processes for better environmental performance and more efficient use of our mineral resources.

Case Study – Copper Metal Production

An example of this type of analysis is shown in figure 4 for two different processing routes for copper metal production. The pyrometallurgical (“pyro”) route involves high temperature smelting of metal concentrates while the hydrometallurgical (“hydro”) route involves leaching of ore heaps at ambient conditions. The Global Warming Potential (GWP) of the hydrometallurgical route, based on electricity sourced from black coal, is much greater than for the pyrometallurgical route. The difference arises from greenhouse gas emissions occurring in the upstream power generation stage, where the electricity consumed in the electrowinning (EW) step of the hydrometallurgical route is produced. This major difference in environmental impacts would not easily be identifiable without taking a life cycle approach.

Figure 4. Life cycle analysis comparison for copper production via pyrometallurgical and hydrometallurgical routes.

What Can be Learnt from Life Cycle Analysis

Mapping the resources and energy embodied in a product system (e.g. the metals, above) is the starting point for decisions on triple-bottom-line performance. It allows the data to be grouped into meaningful indicators for impact assessment (e.g. greenhouse gas emissions), and examined for possible cost reductions. It also enables comparison of products and processes in terms of both cost structure and environmental impacts (e.g. recyclable versus re-fillable containers, aluminium versus steel fabrication, cloth versus disposable nappies, etc).

Using Life Cycle Analysis to Look at the Bigger Picture

Measuring the embodied resources of products and services is a big step forward in our understanding of industrial metabolism, but it does not necessarily give us a complete or accurate picture of the net impacts of particular human activities. Increasingly, manufacturers and users of products and services will be expected to think not only backwards into the world behind the product but also forwards to the impact the product or service will generate during its use, maintenance, and eventual decommissioning and disposal. The major resource impacts of a product or service are not necessarily evenly distributed across these various life-cycle stages. Think of an aging nuclear power plant, for example; how do the savings in greenhouse gas emissions achieved during its use stack up against the costs and impacts of waste disposal and eventual decommissioning of the plant itself?

Extended Product Responsibility

We are already seeing evidence of a growing trend towards voluntary or enforced cradle-to-grave stewardship and extended product responsibility (EPR). In parts of Europe and the USA, “take-back” schemes have been implemented in which product manufacturers are responsible for taking back and disposing of product packaging or the products themselves. Of even more interest, however, is the next step – “cradle-to-cradle” manufacturing - where products are specially designed for successive cycles of "re-manufacturing", and the embodied energy and resources are recovered and used again and again with high efficiency. Mandated product stewardship obligations will be a strong driver in this direction but, even without compulsion, innovations to close industrial metabolic loops will be a source of new business opportunities.

Could we imagine a time when washing machines or even cars, for example, might be provided on the “Xerox” model - i.e., by switching from “product” to “service”. In this scenario, the manufacturers would sell us “personal laundry services” and “personal mobility services” rather than cars and washing machines, and would themselves retain ownership of the actual equipment. Imagine the incentives for resource efficiency, remanufacture, and recycling!

Life Cycle Analysis and the Built Environment

The built environment is one area of the economy where life cycle analysis will have a significant impact. One of the first differences will be a change in emphasis from minimizing capital investment up-front, to minimizing costs over the full life-cycle of a built facility. Owners will be looking not just for “cheap” buildings, but for “efficient” buildings, both in the domestic housing and commercial building sectors. Already significant work has been done to inform decisions relating to architectural design, energy management systems, selection of building materials, etc. Relevant decision support software is being developed in a number of research groups, for example the near-release Life Cycle House Energy Estimator  (LICHEE) program of CSIRO Building Construction & Engineering.

Life Cycle Analysis and Building Design

In selecting the overall design specification for a new building, a large commercial office block for example, it will be increasingly important to compare the range of design possibilities from the LCA point of view. Since the mass of input data lying behind each design is potentially enormous, simple, graphical methods of summarizing and presenting this data will be vital. One such method being applied by Sven Lundie at the University of New South Wales, involves summarizing various impact characteristics of building design on “spider-web” plots that readily allow a quick conceptual comparison of different design options.

Summary

Today’s LCA studies look at the impacts of the “technosphere” on the biosphere - the impact of human activities on natural resources and the environment. There is an important area, however, that has barely been tackled as yet - integration of the social issues around these pathways of resource flow. Essentially we have yet to deal with the full set of trade-offs involving society’s perceived need for a product or service, its impact on the environment, and the issue of who benefits and who is harmed by the activity. Down the track are some very curly questions. Is the product actually useful enough to society to outweigh the costs of impacts on the environment? Is its net effect on society as a whole good or bad? Should we produce it at all? The issue goes way beyond idle contemplation of the miniature throw-away umbrella in your cocktail glass. It goes to the heart of economic activity encompassing the essence of “value” versus “values”. No easy answers here - but plenty of questions needing an answer.

 

Primary author: E.G. Heij

Source: Materials Ausralia, Vol. 34 No. 1, pp. 12-13, Jan/Feb 2002.

 

For more information on this source please visit The Institute of Materials Engineering Australasia.

 

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