Life-cycle assesment and life-cycle thinking in resource and waste management

Life Cycle Assessment (LCA) is a methodological tool used to assess the environmental consequences of activities. In principle, LCA is a holistic tool encompassing all environmental exchanges (resources, energy, emissions, waste) occurring during all stages of the activities life cycle. This tool is most useful, therefore, when applied on products or services for which the life-cycle concept and its stages are clearly defined. LCA is particularly useful because it attributes environmental burdens to specific processes. The steps for performing a proper LCA have been described and standardised in the recent ISO 14040 standards. However, the goal of being as holistic as possible increases both the analytical complexity and the data requirements. LCA can be used for comparisons of alternative options providing equally acceptable solutions to a specific problem, which means it can be integrated to a general decision-making process covering the environmental implications of a decision. More specifically, an LCA can explain and monitor in detail the potential direct or indirect environmental consequences of a decision for the entire life cycle of a system under study. The integration of this life cycle principle to traditional management practices leads to the concept of Life Cycle Thinking (LCT). Moreover, the coordination and subsequent combination of LCA with a Cost-Benefit Analysis (CBA) can cover more aspects of the decision-making, allowing better-informed decisions. The importance of LCA use and LCT is illustrated in many pieces of legislation in national and international context. EU has accepted LCA as a state-of-the-art methodology and has included aspects of LCT in the 6th Environmental Action Programme. p>

1. Introduction to life-cycle thinking in resource and waste management

This section of the Topic Centre website has been prepared in response to the demand for information on the use of life-cycle tools in the fields of resource and waste management.

This section does not claim to comprehensively cover all the possible aspects and applications of Life Cycle Assessment (LCA) (see also the 'links' section for a selection of internet resources). It provides a synthesis of how Life-Cycle Thinking (LCT) and LCA tools can be used in relation to resource and waste management.

The site consists of the following elements:

an introduction to LCA tools specifically designed for resource and waste management
a discussion of the use of life-cycle thinking in EU resource and waste policy
a description of potentials and limitations of the use of LCA in relation to resource and waste management
a library and a collection of links to key documents, discussion papers, and other sources of information on LCA in resource and waste management.

The site compiles, in a synthesised form, the Topic Centre's accumulated expertise in the application of LCA in resource and waste management, including the Topic Centre's projects, and reports from the Topic Centre's library. Visitors are welcome to contact us to recommend reports and articles that would be relevant to include in the library. Finally, the site gives a collection of useful links in relation to LCA and waste management.

2. LCA in resource and waste management

There is an increasing interest among those responsible for management of resources and waste in designing strategies for integrated, sustainable resource and waste management policies.

LCA methodologies can be used in this context as an input to decision-making regarding the choice of waste management systems, or strategic decisions regarding priority resource use. A life-cycle assessment provides an overview of the environmental benefits and costs of the different management options and makes it possible to compare the potential environmental impacts of these options.

LCT when applied in decision making can generate a comprehensive representation of different management options and describe in detail the full implications and consequences of decisions. The value of LCT has been acknowledged in many European legislative pieces including the 6^th Environmental Action Programme.

Using LCA for resource and waste management issues has a slightly different focus than tradi-tional product-oriented LCAs. Most product LCAs do not consider end-of-life phases, or assume a simplified form of disposal. However, a specific modelling of the fate of the substances contained in waste disposed of through incineration, landfill or recycling, is with the current scientific knowledge not an easy task at all.

Typical questions asked in waste and resource LCAs are for example:

When a bag full of mixed municipal waste containing plastics, food, metals, glass, wood, and textiles is incinerated, how much of, e.g., the dioxin emissions can be attributed to plastics? How much to food waste? How much to the metals that catalyse dioxin formation?
How much of the energy released and recovered for electricity production can be attributed to the different materials? What is the type of energy source substituted by energy produc-tion from incineration plants: Is it hydropower, nuclear power or wind power?
What is the material whose extraction is avoided when e.g. 1 kg of steel is recycled? Is it virgin material such as iron ore? Or is it steel scrap?
When in a given region or country incineration is compared to other disposal options, what are the consequences of for instance an increase in the incineration capacity? Is it a de-crease in the landfilling of waste, or does landfill capacity remain constant in the country and waste is imported from other countries to utilise the increased incineration capacity?
How should issues such as carbon storage and binding be taken into account in a waste LCA?

Several LCA tools have been developed specifically for resource and waste management in various countries. Examples of these are:

Decision Support Tool, DST (United States)
Ecobilan Waste-Integrated Systems for Assessment of Recovery and Disposal, WISARD (United Kingdom, France)
EPIC/CSR Integrated Waste Management Model (Canada)
Life Cycle Inventory Model for Integrated Waste Management, IWM-2 (United Kingdom)
Organic Waste Research, ORWARE (Sweden)
EaseWaste (Denmark)

In addition to these, the more generic LCA tools can also be used for modelling waste management systems. General LCA tools are, for instance:

No LCA tool has been designed specifically for resource management, but all tools include the use of different resources in their inventory and databases.

In the LCA tools, resources are classified in different categories such as biotic, abiotic, or energy carriers. Most LCA models also include a methodology for the assessment of the impact described as the extraction/depletion of the resources of the inventory. 'Resources' is therefore one of the impact indicators included, together with climate change, acidification, toxicity, etc. The methodologies for impact assessment of resource depletion can be based on different criteria such as the energy used for their extraction and refinement, or their scarcity in relation to the known world reserves.

3. EU policy context and relevance

Traditionally, EU policy on waste and resource use has been mainly based on data on waste amounts. LCAs offer the opportunity to shift the policy basis from the waste and resource amounts to the potential environmental impacts they cause, including, as far as available knowledge allows it, the related consequences to humans and the ecosystems.

In the Sixth Environment Action Programme of the European Community - Environment 2010: Our Future, Our Choice the European Commission presents sustainable use of natural resources and management of wastes as one of four priority areas. This has led to the development of two thematic strategies on resource and waste management:

In both thematic strategies, the life-cycle approach is emphasised as an important part of the work. More knowledge is needed on the pressures that waste generation and waste management exert on the environment, and their links to possible impacts.

Life-cycle thinking is also a prominent principle in the EU integrated product policy (IPP). According to the Commission's Communication on IPP, life-cycle thinking considers a product's life cycle and aims for a reduction of its cumulative environmental impacts from the "cradle to the grave" or "cradle to cradle". In so doing it also aims to prevent individual parts of the life cycle from being addressed in a way that simply results in the environmental burden being shifted to another part. By looking at the whole of a product's life cycle in an integrated way, IPP also promotes policy coherence. It encourages measures to reduce environmental impacts at the point in the life cycle where they are likely to be most effective in reducing environmental impacts and saving costs for business and society.

4. Application of LCA in resource and waste management

The LCA methodology is a holistic approach to impact assessment in two senses. Firstly, it attempts to include all known environmental impacts potentially arising from an activity. Secondly, it covers all stages in the life of a product, material or service. The method aims at covering all physical exchanges of a product or material's system, and thereby captures any transfer of impacts from one media to another.

Because of the characteristics mentioned above, LCA is a methodology that is best applied to the analysis of the life cycle of products and services. The mentioned elements are usually not included in other environmental analysis or assessment methods, such as risk assessment, input-output analysis, cost-benefit analysis or environmental impact assessments.

The application of the LCA methodology has been officially standardised in the ISO 14040 series. All steps of a proper LCA are described in detail and preferable solutions are given for common problems, such as the co-products issue.

Setting up the spatial and time boundaries of the waste or resources system analysed is the most crucial part of an LCA, given the need to include its interactions with other connected systems. While less common, it is also possible to use LCA to integrate and model environmental impacts that do not happen immediately, but occur with a time lag.

LCAs are based on a large amount of background data, and the results should ideally be presented in a transparent form, that is, allowing tracing back the origin of the data and the background for any assumptions and calculations made. LCA experts appreciate the provision of background data, but it often becomes overwhelming for non-experts. Therefore, the available LCA software tools have to strike a balance between user-friendliness and transparency with regard to equations and calculations.

Together with economic analyses, LCAs of resource and waste management provide a decision-making basis for local, regional and national authorities in such areas as:

Quantifying the potential environmental impacts of a given resource and waste management option
Providing a basis for identification of resources the use of which has the largest impact, and can be priority areas for policy
Providing a basis for comparison of different waste management solutions such as incineration, landfilling, recycling, biodegradation, etc both in environmental and economic terms.

The LCAs that focus on waste management only follow a lightly different methodology. The entire life cycle of a product/material is not examined, but only the end-of-life stage is investigated instead. The reason is that the changes or decisions, that need to be assessed, are confined within the waste management framework. Therefore, a product’s life cycle is only assessed for the part “from gate to grave”.

5. Limitations of the use of LCA in resource and waste management

There are two major challenges in the use of LCA in resource and waste management: data and system boundary knowledge.

5.1. Data

The first challenge is how to cover and quantify all interactions of the analysed resource and waste management system with its surroundings. A comprehensive analysis requires the collection of an enormous amount of data. In many cases it is not possible to obtain this data which leads to many assumptions and simplifications. This data need is the consequence of LCA's ambition of being a holistic tool, both addressing environmental impacts, which are global, regional and local, and following a substance's life from cradle to grave.

Local waste management systems and local resource management systems have generally specific characteristics such as composition and origin of raw materials, emissions from landfills or incineration plants, or energy sources used for electricity supply. LCA studies of such systems require also that specific data be used. However, in the increasingly interconnected economies and systems, where products and waste are imported and exported, the collection of such specific information is difficult and time-consuming. Frequently, knowledge gaps are filled in by qualified assumptions or by import of data from databases and from other regions. Depending on the LCA's objective and scope, the error introduced by such assumptions and data substitutions can be small, or large. Often, the error introduced can be quantified and the assumptions thereby justified.

The quality of an LCA study is not better than the data it uses. Like most environmental as-sessment tools, LCA studies provide results of the potential environmental impacts of one or more systems with a given uncertainty caused by the methodology chosen. In some cases the uncertainty is large; in others small. Therefore, LCA results are useful for identification of trends and significant differences that are robust and not altered by the data uncertainties.

The increasing need from political or research perspective not only for better but also for harmonised data in a European context has lead to an effort by the JRC to create a European Platform on Life Cycle Assessment. This platform includes the European Life Cycle Database which summarises average European data for materials, energy and waste management.

5.2. Knowledge of the analysed system

The second challenge of the use of LCA in waste and resource management is that the impact of these systems is very dependent on local, regional and national conditions, including consumer habits, mode of transport, generation of by-products and energy, or the energy supply systems in place (fossil fuels, biomass, hydropower, nuclear, wind). It is therefore important to make use of local data when possible, rather than importing external data or using the default data.

To correctly set up the boundaries of a system requires specialised knowledge. Resource extraction and waste treatment processes are complex in the number of inputs and outputs, and have frequently outputs of energy (power from incineration plants or landfill gas plants) and by-products (compost, slag, recovered glass, paper, metal scrap). The energy and by-products can enter into other systems, substituting other materials or energy which otherwise would be used. The correlation of a system under study with other surrounding systems (competitive, synergistic etc.) makes it difficult to attribute environmental impacts to a separate process. The rules regulating this allocation of impacts is still considered to be a major challenge and not consensus on a consistent approach has been reached.

The characteristic of waste as a mixture of various materials adds another element of complexity to the use of LCA. Due to the mixed and variable composition of waste, it can be difficult to determine which the materials in waste are that cause a given emission. For instance, are dioxin emissions in an incineration plant caused by combustion of PVC, chlorinated solvents, or chlorine-bleached paper? The lack of exact knowledge of the transfer mechanisms during waste treatment makes it necessary to use different assumptions to allocate emissions to the inputs.

In many cases, the limitations encountered in traditional product LCAs will also apply to LCAs on waste management. The quantification of the long-term (>100 years) impacts from landfilling is a problem yet to be solved. In the absence of knowledge of the long-term impacts from landfilling, some LCAs assume that these emissions are zero, appearing as a better choice than other treatment and disposal options. The toxicity impacts are also frequently neglected because of insufficient science-based knowledge, making the assessments of hazardous waste treatment options difficult.

The uncertainty of assessing the potential contribution of a specific substance to various environmental phenomena is even greater in the toxic impact categories than the non-toxic ones. This fact causes consistency problems across LCA studies, even across different methodologies. Therefore the choice of a methodology and impact categories appropriate for the system under study is quite important.

6. Library

The Topic Centre has collected a library of reports and documents that are central in relation to LCA and waste. Visitors are welcome to contact us to recommend reports and articles that would be relevant to include in the library.

6.1. LCA and waste - Guidelines, methodologies, etc.

Bjarnaddottir, H.J., Fridriksson, G.B., Johnsen, T. & Sletsen, H. (2002). Guidelines for the use of LCA in the waste management sector. Nordtest TR 517, Nordtest, Espoo, Finland.

Bjoerklund, A. & Finnveden, G. (2003). Recycling revisited - Comparing different waste management strategies. Presented at the 10th SETAC LCA Case Studies Symposium 3-4 December 2002, in Barcelona, Spain.

Clift, R., Doig, A. & Finnveden, G. (2000). The application of life cycle assessment to integrated solid waste management. Part 1 - Methodology. Trans IChemE 78, (Part B): 279-287.

Finnveden, G., (1999). Methodological Aspects of Life Cycle Assessment of Integrated Solid Waste Management Systems.Resources, Conservation and Recycling, 26, 173-187.

Finnveden, G., Johansson, J., Lind, P. & Moberg, Ů (2000). Life Cycle Assessment of Energy from Solid Waste. Stockholms universitet/Systemekologi and FOA, Forskningsgruppen för miljöstrategiska studier. fms 137. 198 s., Stockholm, Sweden.

Finnveden, G. and Huppes, G., eds., (1995). Life Cycle Assessment and Treatment of Solid Waste.Proceedings of the International Workshop, AFR-Report 98, Swedish Environmental Protection Agency, Stockholm, Sweden.

Moberg, A, Finnveden, G, Johansson, J & Lind, P (2000). Life Cycle Assessment of Energy from Solid Waste – Part 2: Landfilling compared to other treatment methods . Accepted for publication in the Journal of Cleaner Production.

Sundqvist, J.-O. (1999). Life cycle assessments and solid waste. Guidelines for solid waste treatment and disposal in LCA