Chapter 4
European Assessment Methodologies

Jacques Besnainou

Ecobalance

Over the past 10 years, environmental issues have assumed an increasing priority for government and industry alike. In the United States and in Europe, the emphasis of environmental research has gradually shifted from specific sites to specific products or processes. As a result, specific regulations have been enacted that address the environmental impact caused by specific products. One example is Executive Order 12873, signed by President Bill Clinton October 20, 1993, which requires in section 503 that the Environmental Protection Agency (EPA) "issue guidance that recommends principles that executive agencies should use in making determinations about the preference and purchase of environmentally preferable products."

This is one of several reasons why tools are needed to scientifically assess the overall environmental performance of products and their associated industrial systems. In numerous industrial countries, life-cycle assessment and its most developed component, life-cycle inventory analysis, are now recognized as belonging to that category of tools. Life-cycle analysis provides quantitative information about of the environmental impacts of industrial systems. By offering an unbiased analysis of entire industrial systems, life-cycle analysis has shown that the reality behind widely held beliefs regarding "green" issues is more complex than one might expect.

Wood is a material of choice for many industrial and commercial products. More and more life-cycle analyses are performed for wood-based products, and the methodology is rapidly evolving, especially in Europe.

This chapter details recent developments in Europe for both the life-cycle inventory methodology and life-cycle impact assessment methodology.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 36
Chapter 4 European Assessment Methodologies Jacques Besnainou Ecobalance Over the past 10 years, environmental issues have assumed an increasing priority for government and industry alike. In the United States and in Europe, the emphasis of environmental research has gradually shifted from specific sites to specific products or processes. As a result, specific regulations have been enacted that address the environmental impact caused by specific products. One example is Executive Order 12873, signed by President Bill Clinton October 20, 1993, which requires in section 503 that the Environmental Protection Agency (EPA) "issue guidance that recommends principles that executive agencies should use in making determinations about the preference and purchase of environmentally preferable products." This is one of several reasons why tools are needed to scientifically assess the overall environmental performance of products and their associated industrial systems. In numerous industrial countries, life-cycle assessment and its most developed component, life-cycle inventory analysis, are now recognized as belonging to that category of tools. Life-cycle analysis provides quantitative information about of the environmental impacts of industrial systems. By offering an unbiased analysis of entire industrial systems, life-cycle analysis has shown that the reality behind widely held beliefs regarding "green" issues is more complex than one might expect. Wood is a material of choice for many industrial and commercial products. More and more life-cycle analyses are performed for wood-based products, and the methodology is rapidly evolving, especially in Europe. This chapter details recent developments in Europe for both the life-cycle inventory methodology and life-cycle impact assessment methodology.

OCR for page 36
Life-Cycle Analysis: Basic Principles Life-cycle analyses are concerned with the impact of extended systems sequences of industrial operations on the environment. In the case of a product, the system encompasses the entire life-cycle, from raw material extraction to the different end-of-life management alternatives (landfilling, incineration, recycling, reuse), including the manufacturing stages, transportation, distribution, use, and waste collection. A complete analysis involves three main steps, and several tertiary ones: The inventory is used to calculate material and energy inputs and outputs from the system. This phase includes: —the definition of system boundaries (which steps are included in the system and which are not) regarding the goal and scope of the project; —data collection needs for each step previously in the system; and —calculation of the final inventory. The detailed inventory results are classified into five main categories: raw material consumption, energy consumption, air emissions, water effluents, and solid waste. The impact assessment, in which the flows compiled in the inventory are translated into environmental impacts (natural resources depletion, greenhouse effect, photochemical smog, water toxicity, and so on). The improvement analysis, evaluates needs and opportunities for reducing the environmental burden associated with the system studied. This phase is connected to the initial goal and scope of the project. Methodology status Despite the lack of official standards, many harmonization schemes have greatly helped reduce existing differences in life-cycle analysis methodology. The situation is different for each step of the analysis: The inventory phase is now well settled and there are almost no differences among the methods used by experienced practitioners. The methodology has been summarized in a U.S. EPA publication, Life-Cycle Assessment: Inventory Guidelines and Principles, and in the proceedings of Society of Environmental Toxicology and Chemistry's (SETAC) workshop, Guidelines for Life-Cycle Assessment: A Code of Practice. The impact analysis phase is currently under development, and there is as yet no generally accepted methodology. However, some techniques have been developed and yield practical results, and Ecobalance, my company, has gained experience in using them. The improvement analysis phase is related to management consulting practices and relies more on practitioners' industrial experience and their ability to understand and deal with clients' needs, than it does on actually formulating a methodology. The International Standardization Organization (ISO) is currently working to standardize the methodology under the ISO 14000 series.

OCR for page 36
Inventory Methodologies: General Principles for System Boundaries The theoretical principle of life-cycle analysis dictates that each material and constituent should be traced back to natural resources (energy and raw materials) taken from the environment or to substances and energy released to the environment (emissions to air, water, and soils). These could be called "elementary flows" (crude oil, iron ore, CO2 emissions). Each time a nonelementary flow (diesel oil, steel) appears, practice calls at least theoretically for system boundaries to include the production processes leading to this product and its end of life, until all elementary flows induced by its production (and use) are accounted for. Extension of the system allows reduction of nonelementary flows to elementary ones (Figure 4-1). Figure 4-1 System boundaries.

OCR for page 36
Until recently, wood was considered a natural resource; an input to the system. However, more European countries are now considering this assumption false and are leaning toward considering wood as an intermediate flow, inside the system under study. So wood is no longer a raw material; the seed is at the beginning of the cycle. Several studies set to begin in 1996 consider forests as industrial systems. The European Commission, under pressure from northern European countries, is considering life-cycle analysis studies of oaks, spruces, and beeches. Concurrently, the French Ministry of the Environment is contemplating a life-cycle study of poplars and Oregon pines. The forest can be seen as an industrial system, which includes all forestry activities, and as a natural system, which is the intersection of the main biogeochemical cycles. Forestry Activities And System Boundaries The reasonable upstream limit of the forest system boundaries is the seed itself, because the inputs and outputs (fuel, fertilizer) required by a tree to produce one seed are negligible. Thus, the forest is a system that uses energy and material input from the environment and generates emissions to the environment in the process of converting seeds to harvested wood. Inputs and outputs of several steps are taken into account: nursery; site preparation; planting; tree growth, including herbicide and fertilizer application and CO2 uptake; and harvesting (Figure 4-2). For each step, data are collected on the consumption of water, fuel. herbicides, and fertilizers. The system boundaries are extended to include the production of the main inputs consumed—fuel and fertilizers—on the basis of their weight. Figure 4-2 Steps in the forest system boundary.

OCR for page 36
Note that, in reality, a significant fraction of the wood used in forest products comes from trees grown from natural regeneration rather than from planted seedlings. Naturally regenerated trees generally carry a lower environmental burden than do planted trees, because they avoid the chemical and energy consumption associated with nursery, site preparation, and fertilization. Therefore, considering a forestry system model in which 100 percent of the harvested wood comes from planted trees ensures that the burdens estimated in the life-cycle inventory for the forestry step are conservative. Forests as Natural Systems Forests, like other natural systems, are complex (Figure 4-3) and scientific knowledge about them is limited. There is both uncertainty in the model parameters and natural variability in the real forest systems being modeled as far as the flows of carbon, hydrogen, oxygen, nitrogen, phosphorus, and potassium are concerned. Nonetheless, the specific nature of wood should be reflected in the life-cycle inventories and taken into account when interpreting these inventories. This is particularly relevant for the treatment of emissions of CO2 and other greenhouse gases, and for the treatment of the energy, and mass indicators that might be included in the life-cycle inventories. Carbon dioxide uptake and renewability are studied in the following sections. CO2 Uptake and Release The carbon content in wood products is derived from the CO2 absorbed by trees when they grow (photosynthesis). The carbon atoms are either released at the end of life of the products, in the form of CO2, CO, hydrocarbons, or methane molecules, when the products are burned or decomposed in landfills, or during Figure 4-3 A tree and its environment: main physical inflows and outflows.

OCR for page 36
composting, or they can remain trapped in landfills for decades if decomposition is incomplete. From the life-cycle inventory of the releases we must subtract CO2 uptake or sequestering during forest growth as part of the total carbon cycle. Renewability Wood is a renewable resource. Forest net growth, defined as total growth less mortality, in the U.S. (22,525 million cubic feet per year in 1986) currently exceeds forest harvesting (16,450 million cubic feet per year) (Waddell et al., 1989). No change in this proportion is expected for decades to come. This is why consumption of renewable energy resources should be distinguished in life-cycle inventories from consumption of nonrenewable energy resources (such as oil and gas). This does not mean that harvesting a tree has no impact on the equilibrium of the forest. Restocked species are not necessarily the same as those harvested, and regions harvested are not necessarily the same as those planted. But this observation is more relevant from a biodiversity or sustainability point of view than from a renewability point of view and should be addressed in a subsequent impact assessment stage. The issue of the renewability of wood is separate from the issue of CO2 uptake, which should be accounted for regardless of the issue of renewability. Whether a harvested tree is replaced by a replanted tree or not is independent of the fact that the harvested tree has consumed CO2. Life-Cycle Impact Methodologies: Ecopoints System ''Ecopoints'' are used to represent the environmental load of a system, based on the inventory of inputs to and outputs from the system (the life-cycle inventory). The lower the score, the better the environmental performance as measured with ecopoints. The process for calculating ecopoints is as follows: Ecofactors are defined for items typically found in life-cycle inventories. Each item in the inventory (for which an ecofactor exists) is then multiplied by its ecofactor. The ecopoints have the same dimension and can be added up to obtain four separate partial scores for air emissions, water releases, energy consumption, and waste outputs. The total score—the total environmental load—is then obtained by adding up the four partial scores. The Ecopoints method was developed in Switzerland. It is fully explained in Ahbe et al. (1991). An ecofactor for a given item is calculated from an estimate of the total annual emission (or consumption) of the item in the country of refer-

OCR for page 36
ence (annual flow, F) and the maximum acceptable annual emission (or consumption) of the same item for the country of reference (critical flow, Fk). The ecofactor (E) is then given by: E = (1/Fk)*(F/*Fk)*1012. The lower the critical flow, the higher the ecofactor. The closer the annual flow is to the critical flow, the higher the ecofactor. A constant (1012) is used for improving the readability of the results. The ecopoint score (S) for a given item is given by S = E*X. X is the amount of the item in the inventory. Because the ecopoints have been developed only in Switzerland so far, the values for F and Fk used in Europe are those given for Switzerland. Critical-Volume System Critical volumes also were devised in Switzerland. The method is presented in Ecobalance of Packaging Materials (1990). Critical volumes are used in addition to an energy indicator and a solid-waste total, to build what the authors call an "eco-profile," based on inventories or ecobalances of the production of materials and on their end of life, as estimated in Switzerland. Critical volumes are calculated for air emissions and water releases. The critical volume for a given item amounting to X mass units in the inventory is given as critical volume = X/limit value. The limit values are taken as regulatory limits. There are limit emissions values for air, and limit emission values for water (when emissions limits are missing for air releases, then emission limits are used after an appropriate scaling). Swiss regulation is used for most regulatory limits. Critical volumes corresponding to air emissions for which a regulatory limit coexists are then added up to obtain a total air critical volume. Critical volumes corresponding to water releases for which a regulatory limit exists also are added up in order to obtain a total water critical volume. Environmental Priority Strategies A detailed description of the environmental priority strategies (EPS) system is found in Steen and Ryding (1992). The Environmental Priority Strategies system is one of valuation, in which emissions of substances to the environment and extraction of resources from the environment are common measures, that can be compared or added. The mathematical procedure is as follows: each quantity emitted or extracted is multiplied by its corresponding environmental load index. The result is an environmental load value. The dimension of this quantity is the same for all emissions and extraction; it is called the ELU, or environmental load unit, 1 ELU amounts to ECU in OECD countries. The EPS report consists of long tables with environmental load indexes.

OCR for page 36
There are 20 raw materials, including fossil gas, oil, aluminum, and copper, for which such an index is defined. There are 14 chemicals that can be emitted to the air or to water and for which such an index is defined. Among them are CO2, ethene, and SO2. There are four types of land use that can be assessed. The index is based on a number of so-called safeguard subjects: biodiversity; human health; production; resources; and aesthetic values. These safeguard subjects are chosen because the Swedish Parliament has decided to protect human health, preserve biologic diversity, maintain a long-term housekeeping of natural resources, and protect the natural and cultural landscape. For each subject, a valuation of the basis of the willingness to pay has been derived. This willingness to pay concerns an average estimated societal value; for example, 106 ECU for excess death. The relation of emissions and extraction with impact types is more scientific, although many uncertainties are present and many assumptions have been made. An example of this is the impact of 1 kg CO2. There are impacts on health, biodiversity, and production; some impacts are negative, others are positive. The greenhouse effect has several negative effects; one of them is drowning due to a rise in sea level. A positive effect is a decrease in the occurrence of cardiovascular diseases. Eight impacts are considered, and the sum of all partial environmental load indexes yields the net environmental load index for 1 kg CO2 emitted to the air. Before all, it should be noted that the EPS is a system under development. Nevertheless, several critical remarks apply here. The first concerns the valuation of different types of safeguard subjects. It turns out that depletion is highly valued compared with human health. The valuation of depletion is derived from the possibility of recovering materials from dump sites, for example. For human health, a completely incomparable method of valuation is used. The result is that a human being is not even worth his weight in silver! Another objection concerns uncertainty with respect to the impacts of emissions. Whereas some people claim the greenhouse effect does not even exist, it is at least awkward to attribute a rise of sea level—and a concomitant increase in death by drowning—to emissions of greenhouse gases. The extrapolation in terms of reduced life expectancy due to both positive and negative contributions is even more problematic. CML Classification System The Centre of Environmental Science of Leiden University or Centrum Milieukunde Laden (CML) life-cycle assessment method of comparing alternative products on the basis of environmental effects has four steps; goal definition,

OCR for page 36
inventory, classification, and evaluation. A description can be found in Heijungs et al. (1992). In the goal definition phase, the subject of study is demarcated, questions to which the study must give an answer are identified, and a functional unit is defined. In the inventory stage, a table is generated of the intervention in the environment for one functional unit. Apart from complete and detailed process data, assumptions on recycling and allocation must to be integrated in the inventory table. During the classification component, the potential environmental impact of the interventions in the environment is determined. In the evaluation phase, the results of the classification are evaluated. Selection of Environmental Problem Table 4-1 gives a standard list of environmental problem types. Other problems might be included if they do not coincide with problems already listed. Definition of Classification Factors For each problem, classification factors are defined. For depletion of abiotic resources, the known reserves determine the score. Depletion of biotic resources is measured by a biotic depletion factor (BDF), determined by the reserves and the reserves-to-production ratio. In the CML guide, these two problem types have had little attention. Factors are lacking for all but a very few resources. The translation from emissions into contributions to pollution problems is worked out in great detail. This translation is acquired by multiplying the emission by a factor determining the substance's contribution to an environmental problem, relative to a reference substance. For the greenhouse effect, emissions TABLE 4-1 Environmental problem types Depletion Pollution Damage Depletion of abiotic resources Enhancement of greenhouse effect Damage to ecosystems and landscapes Depletion of biotic resources Depletion of ozone layer Human toxicity Ecotoxicity Photochemical oxidant forming Acidification Nitrification Waste heat Odor Noise Victims   Source: Centrum Milieukunde Leiden (CLM). Leiden, The Netherlands.

OCR for page 36
are translated into CO2-CFC-11 equivalents. The calculation of the equivalents per substance are based on general environmental modeling, taking into account the potential effects, environmental behavior, extinction rate, and the environmental compartment to which the substance is emitted. For damage problems, simpler factors are defined. For ecosystems and landscape damage, area is the factor; for people, it is the number of victims. Creating the Environmental Profile The environmental profile is created by presenting the results of the effect scores for all considered alternatives on all selected environmental problems, in tables, graphs, or both. The alternatives can thus be compared by their scores for each environmental problem separately. Normalization of the Effect Scores The effect scores from the environmental profile can be "normalized" by comparing them with a reference effect score, for example, to the yearly world total contribution to a given environmental problem. This can help with interpretation of the environmental profile, and in fact it can be viewed as the first step of the evaluation. A "normalized environmental profile" then emerges. Conclusion In Europe, a consensus is now emerging to consider tree harvesting as part of the life-cycle system boundaries. This implies a careful inventory, and knowledge of all emissions occurring during tree growth. On the impact assessment side of the methodology much controversy remains. However, methodologies such as the CML classification system, which makes a clear distinction between the clarification and valuation steps of the impact assessment methodology, seem to gain more and more ground. References Ahbe, S., A. Braunschweig, R. Mueller-Wenk, Methodologie des Ecobilans sur la Base de l'Optimisation Ecologique, Cahiers de l'Environnement no. 133, Office Fédéral de l'Environnement, des Forêts et du Paysage (BUWAL), Berne Octobre 1991. Ecobalance of Packaging Materials - State 1990, Environmental Series no 132, Swiss Federal Office of Environment. Forests and Landscape (BUWAL), Bern, February 1991. Environmental Protection Agency. 1993. Life-cycle assessment: Inventory guidelines and principles. EPA/600/R-92J245. Washington, D.C.: Government Printing Office. Heijungs, R. (ed), J.B. Guinée, G. Huppes, R.M. Lankreijer, H.A. Udo de Haes, and A. Wegener Sleeswijk. 1992. Environmental life-cycle assessment of products. Guide and Backgrounds. NOH report 9266 and 9267; Leiden, The Netherlands.

OCR for page 36
Society of Environmental Toxicology and Chemistry. 1993. Guidelines for life-cycle assessment: A code of practice. Steen, Bengt, and Sven-olof Ryding. December 15, 1992. The Environmental Priorities Strategies Report. IVL. Sweden. Waddell, K.L., D.D Oswald, and D.S. Powell. 1989. Forest statistics of the United States, 1987. USDA Forest Resource Bulletin PNN-RB-168. Washington, D.C.: Government Printing Office.