Normalization figures for Dutch territory, Dutch consumption and West European territory

Three reference levels for normalization in LCA

By H. Blonk and M. Lafleur (IVAM); R. Spriensma, M.J. Goedkoop and S. Stevens (PRé Consultants), A. Agterberg, B. van Engelenburg and K. Blok (State University Of Utrecht). Commisioned by RIZA and VROM.

• Background and objectives
• Method
• Methodological choices
• Leading principle in drawing up normalization figures
• Qualitative uncertainty assessment
• Relation between the normalization levels
• Results
• Normalization levels
• Explanation of reliability
• Explanation of applied method for drawing up normalization figures
• Recommendations

Background and objectives

In this study normalization figures are derived for three different levels for the impact categories as defined in the Dutch methodology for LCA [Heijungs et. al in 1992]. Those levels are: 

• Dutch territory, concerning all environmental interventions in one year related to human activities on Dutch territory;
• Dutch consumption, concerning all environmental interventions in one year related to the consumption of Dutch end consumers, including the total chains of production and waste processing for this consumption;
• West European territory, concerning all environmental interventions in one year related to human activities on West European territory.

The underlying idea for drawing up different normalization levels is that they are often applied in practice because they are associated with policy levels or levels of operation of companies. This study does not support the choice of any specific normalization level.  

The environmental impact categories for which normalization figures are drawn up are: depletion of abiotic resources, enhancement of greenhouse effect; depletion of the ozone layer; human toxicity; aquatic ecotoxicity; terrestric ecotoxicity, photochemical smog; acidification; nutrification. In addition normalization figures are drawn up for two (additional) economic parameters, namely energy use and dumping of solid waste. These are often key parameters with regard to the environmental impact and which are relevant for Dutch environmental policy. 
 
An important motivation for this project was the fact that several sets of normalization figures per level were applied, while the reason for differences in the figures is often obscure. This hampers the interpretation of LCA results. Therefore, an important objective of this study is to derive normalization figures in a transparent and consistent way. 

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Method

Starting point is that normalization figures should be determined according to the method described in the Dutch LCA guide of 1992. However, the LCA guide allows the LCA user to make choices on several points. This is relevant in the case of allocation and system boundaries but also in the case of the definition of the parameters energy and solid waste to be dumped. The fact that normalization figures are drawn up for subsystems of the world also means that system boundaries have to be defined, which is especially relevant for the definition of depletion of abiotic resources. 

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Methodological choices

A. delineation of pesticides emissions in agriculture 

Pesticides emissions are calculated on the basis of two types of demarcation of the economical and the environmental system, resulting in two normalization figures for terrestric ecotoxicity: A low value on the basis of the assumption that agricultural soil must be considered as part of the economic system, meaning that no contribution of pesticide emission to terrestric ecotoxicity is calculated. A high value is calculated on the basis of the assumption that agricultural soil is part of the environmental system and that all pesticide use results in a emission to the soil, excluded that part which is released to water (approx. 1%). It should be noticed that the low value is an underestimation of terrestric ecotoxicity caused by agriculture, since emissions also occur to natural soil and the high value is an overestimation, since part of the pesticides vaporize or will remain in the product.  

B. definition of environmental themes and parameters  

1) depletion of abiotic resources  

Defining the use of abiotic resources for regions or subsystems of the world is not an easy task, since many definitions are possible and a certain normativity in defining seems inevitable. A basic issue in defining the use of abiotic resources on Dutch territory is what has to be allocated to Dutch territory, considering the discrepancy between exploitation of abiotic resources on Dutch territory and use of abiotic resources on Dutch territory. We have chosen to draw up normalization figures for depletion of abiotic resources on Dutch territory on the basis of apparent consumption figures on abiotic resources for the Netherlands, defined as import + exploitation - export - mutations of resources - bunkers. For Western Europe and for the calculation of normalization figures on abiotic depletion for Dutch consumption the same definition is applied. 

This can be considered as a practical solution of the described allocation problem, made against the backdrop of the many initiatives with regard to the development of improved methods for characterizing depletion of abiotic resources. 

2) energy  

For the definition of energy use the starting points of the Dutch statistics of Central Bureau of Statistics are applied, which implies that all energy carriers used for the production of energy are incorporated in the calculation of Dutch energy use. Therefore, sustainable energy carriers are included (except household wood use). Use of energy carriers applied as a raw material for the production of e.g. plastics is also considered as energy use, despite the fact that the inherent energy in the products is not used yet. A part of this energy is included in the Dutch energy balance (energy recovery waste incineration). Normalization figures for energy use are expressed in Low Heating Value and High Heating Value. 3) Solid waste to be dumped 

Solid waste to be dumped concerns material that is disposed of due to production and consumption activities and that is finally dumped on a dumping site after waste processing (like incineration wastes, etc.). The amount of solid waste to be dumped is measured at the time of dumping, so the reduction of weight due to degradation of organic material is not included. 

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Leading principle in drawing up normalization figures

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Qualitative uncertainty assessment

In the case of the characterization untrustworthiness concerns the uncertainties in equivalency factors due to changed insights in underlying assessments (e.g. changes in MTC which are applied to draw up human toxicity scores).  

Uncertainty is characterized in three categories: small, moderate and considerable in relation to the relevance of the uncertainty of normalization figures in the interpretation of LCA results of a specific product. (see for a  explanation the table further on). 

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Relation between the normalization levels

Normalization figures of West European territory are partly derived from authoritative European data sources and in case of omissions, these data sources are completed with estimates on the basis of Dutch normalization figures. Especially the West European figures on ozone depletion and the different ecotoxicity scores are strongly dependent on Dutch information on these topics. 

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Results

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Normalization levels

• Dutch territory, concerns all environmental interventions in one year related to human activities on Dutch territory;
• Dutch consumption, concerns all environmental interventions in one year related to the consumption of Dutch end consumers, including the total chains of production and waste processing for this consumption;
• West European territory, concerns all environmental interventions in one year related to human activities on West European territory.

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Explanation of reliability

The qualification categories are defined as follows: 

S(mall) implies that the uncertainty is not thought to be relevant for the practical application of normalization in LCA's. In other words, the uncertainty in the normalization figures is considered small in comparison to the uncertainties in most LCA's. In quantitative terms this implies that the uncertainty is estimated not to exceed a range of plus or minus 25%. 

M(oderate) implies that the uncertainty is relevant for the practical application of normalization in LCA's. The uncertainty in the normalization figures is considered to be in the same order of magnitude as important types of uncertainties in LCA, like for instance the uncertainty caused by allocation. It is estimated that the uncertainty range does not exceed the normalization figure by ± factor 2. (=-50% +100%) 

C(onsiderable) implies that the uncertainty is a main factor to be taken in consideration in the interpretation of the results of a LCA.  

The uncertainty in the Normalization figures for Dutch consumption is higher than in Dutch territory due to the fact that the figures for Dutch territory were an important source for deriving normalization figures in which several assumptions were made and additional material is used. No estimation of the resulting uncertainty has been carried out. Also for West European figures using largely other sources no estimation has been made of the uncertainty. 

terrestric ecotoxicity low concerns only industrial emissions registered by Dutch 'Emissieregistratie' 

terrestric ecotoxicity high is terrestric ecotoxicity low plus use of pesticides in agriculture minus that part of pesticide use that is released to surface water 

depletion of abiotic resources and energy use is defined as import + exploitation - export - stock mutations - bunkers; in energy use biomass sources are also included.

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Explanation of applied method for drawing up normalization figures

The normalization figures concern the impact categories as defined in the Dutch LCA guide of 1992 and are expressed in the same units as applied in this guide. No adjustments have been made to the definition of characterization formulas described in this guide and no adjustments have been applied with regard to the characterization factors, despite the fact that new information has become available on the contribution to impacts as defined in the LCA guide (especially relevant for toxicity scores). On the other hand additional characterization figures are drawn up for a number of important eco-toxic releases which were not published in the guide of 1992. 

The normalization figures of the three different levels are related to each other in different ways. The normalization figures of Dutch territory and the data sources and conversion techniques applied for drawing up these figures are the most important sources for drawing up normalization figures for Dutch consumption. By applying the so called input-output analysis normalization figures for Dutch consumption could be derived out of figures for Dutch territory in which the crucial assumption has been made that the environmental burden of industrial production per unit money abroad is equal to Dutch industrial production. 

Normalization figures of West European territory are partly derived from authoritative European data sources and in case of omissions, these data sources are completed with estimates on the basis of Dutch normalization figures. Especially the West European figures on ozone depletion and the different eco toxicity scores are strongly related to Dutch information on these topics. 

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Recommendations

There are two main reasons for actualization. The first reason is the accuracy of normalization figures. A normalization set is adequate only for a certain period . This depends on differences in the speed of changes in the normalization figures, which are induced by for example environmental policy.  The second reason for actualization might be adaptations in characterization methods or adoption of additional methods. 
It is recommended to develop a maintenance plan for normalization figures in which amongst others the motivations for actualization mentioned above are taken into consideration. 

Improving of normalization figures for Dutch territory 

It is recommended to focus follow-up research on improvements of normalization figures of Dutch territory on the following items: 

• quantification of uncertainties of normalization figures , including all cause factors, like uncertainties and incompleteness in data sources, data treatment techniques and equivalency factors;
• making demarcations on activities and emissions more explicit, which activities and emissions are excluded in data sources on national level and for what reason;
• more complete modeling of emissions to soil, including the consistency in system boundaries between economy and nature over all activities and the modeling of emissions.

Improving of normalization figures Dutch consumption

It is recommended to focus follow-up research on the improvement of normalization figures of Dutch consumption on the assumptions made in the input-/output analysis, such as the examination of : 

• the allocation of environmental interventions to input-/output sectors;
• the allocation of environmental burden of Dutch production over consumption and export;
• assumptions made for the environmental burden of import.

Furthermore, for the improvement of normalization figures it is important to have reliable figures on environmental interventions due to the extraction of biotic and abiotic raw materials abroad. Therefore it is recommended to perform an inventory analysis for a set of important raw materials for the Dutch economy. 
 
Improving of normalization figures for West European territory 

The following subjects need special attention in further research on West European figures: 

• the consistency of applied definitions of environmental themes between the countries;
• the reliability and completeness of data sources;
• a further development of the method for filling data gaps of environmental information of member countries. 

RIZA werkdocument [working document] 97.110X, July 1997.

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