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Handbook on environmental assessment of products

2. The simplified LCA

The life-cycle assessment described in this Handbook is different from the standard LCA in two crucial respects:

1. Data collection is limited, as attention is mainly focused on inputs (raw materials and ancillary materials)
2. Environmental assessment is carried out as the level of detail grows.

The main element of simplification concerns the preliminary environmental assessment. It is then possible to work towards an increasingly detailed LCA, although more detailed impact assessment will typically only be carried out for a limited area. This is the main concept behind the stepwise method – a key element of the simplified environmental assessment.

The simplification may be so pronounced that the end result is not a life-cycle assessment, but merely an environmental assessment based on the life-cycle perspective.

2.1 The principles behind the simplification

There is widespread agreement that the main elements of the LCA cannot be compromised. This is to say that you cannot decide to omit consideration of the goal and scope definition (see Chapter 1) or limit yourself to addressing specific phases of the life-cycle [Christiansen et al., 1998] when you wish to simplify the LCA. Rather, simplification is carried out by limiting the collection of data, which is usually the most time-consuming task.

The next principle of this simplification is to work step by step, continuously assessing whether the questions asked can be answered with sufficient certainty on the basis of the steps completed so far.

Examples of questions that help establish an overview of a product life-cycle would be:

	Where in the product life-cycle do the most significant negative environmental impacts occur?
	What activities cause the most significant negative environmental impacts?

Later, it may be relevant to ask more specific questions, e.g.:

Is it better to use plastic than recyclable copper (for a specific component)?

The simplified environmental assessment is a tool for finding answers to such questions, but there may be considerable uncertainties involved. If so, more information must be collected and the procedure must be repeated.

The difference from a traditional LCA is that this additional data collection can be restricted to a smaller sub-segment of the life-cycle or product. If, for example, you are examining a water heater and it turns out that heat losses during the use phase is the most important issue, you can focus exclusively on collecting further data about that.

2.1.1 Why stepwise LCAs?

Working step by step is the key. This approach ensures that you do not work harder than is necessary. At the same time, the work carried out during the initial steps can be used later as the process develops. For each step, you must consider whether the conclusions that can be drawn might change if new information is introduced. If it seems likely that the conclusions would change, you should continue your work.

The process can be visualised as a pyramid:

Figure 2.1
Stepwise structure of the simplified LCA

The MECO chart provides an overview of the relevant product lifecycle. It presents indicators for environmental impacts within the following categories: Materials, Energy, Chemicals, and Other. The MECO chart is prepared at the same time as the preconditions for the system and a description of the phases completed by the product. All this information can be used in subsequent work with environmental assessment by means of a PC tool. It just means that more data will be fed into the model. The Focus LCA is not addressed individually, as it is an extension of the environmental assessment in the PC tool. In Focus LCAs, extra data is collected to focus on individual areas.

The pyramid (figure 2.1) symbolises how the level of detail and the amount of work increases as you work your way towards the bottom of the pyramid. It also shows how each step always makes use of data and knowledge from the preceding steps. You can stop after the first step, or you can elect to continue.

The approach used in this Handbook is illustrated in figure 2.2. The figure shows the steps involved in environmental assessments and the places where it may be necessary to collect further data and information or to speak with others.

All steps are carefully described in Part B of this Handbook, also known as the Cookbook. For now, here is a brief rundown to provide an overview of the approach.

Step One (1) is to select the product and define the goal of the environmental assessment. The goal is very important, and discussion with others is particularly important as this stage. The final results will be compared to the goal, and if the goal is not sufficiently clearly defined, you have no way of knowing whether you have enough information. More details on this issue can be found in Chapter 1 in Part B.

The life-cycle of the product (2) is a description of what happens during the individual phases, i.e. raw materials, production, use, disposal, and transport. If you recognise large gaps in your data basis at this early stage, you should seek out more information. A more detailed description of the methods used for this purpose is provided in Chapter 2.

The information about the product life-cycle forms the basis for the preliminary environmental assessment (the MECO chart (3)). This environmental assessment takes the form of a chart illustrating the life-cycle phases and sources of environmental impacts in visual terms, see table 2.1. The guidelines on how to carry out simplified environmental assessments can be found in Chapter 3.

The MECO chart is used to carry out an inventory and an impact assessment at the same time. The advantage of the MECO structure is that the individual sources of environmental impacts do not, in fact, overlap, and that it covers all significant environmental issues. This means that it is possible to assess whether any weighting problems exist, e.g. between energy consumption and chemicals.

Figure 2.2

The steps of the simplified LCA. D stands for "Dialogue", i.e. a discussion with a relevant party. The numbers refer to the chapters in part B, which provide more in-depth descriptions.

The stages leading up to and including the MECO chart constitute the preliminary environmental assessment and the first step of the simplified LCA. At this point, it is important to pause and consider whether the chart provides a sufficient basis for making the desired conclusions, or whether you need to move on to the next step. A dialogue box has been inserted to emphasise that you need to discuss this with someone else. In particular, you should team up with an "expert" to decide whether you should move on to the extended chemical assessment or some other type of impact assessment which is outside the scope of this handbook.

Table 2.1
The MECO chart used for the preliminary environmental assessment

You can also stay at the MECO chart level to find additional data.

It should be emphasised that the MECO chart comes with appendices with data (appendix B at the back of the book) that make it possible to fill in the chart using nothing more than paper, a pencil, and a pocket calculator.

Once the MECO chart has been completed, you need to assess whether you have a sufficient basis for answering the questions posed, or if you need to continue your work.

Possible reasons for wanting to continue an LCA by means of a PC tool (4) include:

	A desire to weight various environmental impacts
	A desire to have a model which can be adapted to suit similar products quickly and easily
	A need to make use of databases
	A need to incorporate greater detail as regards inputs and outputs than the MECO chart allows for.

The extended chemical assessment (Chapter 5) represents another opportunity for carrying out further work. No matter which environmental assessment you choose, the results must be documented in a report (Chapter 6).

The central element of the simplification is an assessment of the reliability of the LCA results in relation to the goal. The simplified LCA is based on the recognition that some conclusions can be made at MECO chart level, while others can only be made later. This means that you need to make your work target-specific, making conclusions only when your basis for doing so is sufficiently certain. Special attention should be paid to the fact that results which are to be used externally, i.e. outside of your company, must be very reliable.

2.2 Comparing ISO, EDIP, and the MECO chart

Table 2.2 features a comparison of the general principles for lifecycle assessment according to the ISO 14040 series, EDIP, and the MECO chart. Comparisons show that the overall principles for ISO and EDIP are identical, whereas the MECO chart differs from the others in terms of scope definition, data collection, and impact assessment.

The philosophy behind the principles of the MECO chart is that if an environmental assessment can be carried out in a simple way; that is exactly what you do. This is why a number of simplifications have been introduced when compared to ISO and EDIP. These simplifications make it easier to carry out environmental assessment, but also limit the potential uses of the result. Most companies will, however, benefit greatly from a simplified environmental assessment.

As regards data collection, minimum requirements (on the raw materials and production lists) have been defined for the MECO chart, but you can still add more data. The assessment of resource consumption runs parallel to the one carried out within EDIP, but apart from this, assessment by means of the MECO chart is simpler.

Energy is converted into primary energy and resource consumption values on the assumption that the energy consumed comes entirely from oil. This is a somewhat crude assumption, but it is useful when relating resource consumption from raw materials to energy consumption.

It is difficult to simplify environmental assessment for chemicals. Here, inputs (i.e. chemicals consumption) are also used as the basis. Each chemical is classified according to whether it is listed on the List of Dangerous Substances, the List of Undesirable Substances, or the Impact List. This is why it is often necessary to carry out an extended chemical assessment for products which contain many chemicals.

These differences apply only to the preliminary environmental assessment. When an LCA is carried out by means of a PC tool, you will mainly use existing data, and you may also be considering only a small part of the total product life-cycle. The extended chemical assessment falls outside the scope of the LCA, but the information gathered could be used to calculate factors for toxicity which could then be used later within the PC tool.

Table 2.2
Comparison between ISO, the EDIP method, and the MECO chart

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