Environmental Life-Cycle
Assessment: A Tool for Public and Corporate Policy Development
Raymond R. Tan, MSa
and Alvin B. Culaba, RME, PhDb
aChemical Engineering
Department, De La Salle University – Manila
bMechanical Engineering
Department, De La Salle University – Manila
SUMMARY
Life-cycle assessment (LCA) is a methodology for
analyzing the environmental interactions of a technological system with the
environment. Early forms of LCA were
used in the United States in the late 1960s for defining corporate
environmental strategy, and later in the 1970s by government agencies as an aid
for developing public policy. In the
late 1990s, LCA emerged as a worldwide environmental management tool in the
form of the ISO 14040 series. Despite
relatively limited use in the Philippines, there is considerable potential for
its utilization in both public and private sectors. For example, LCA can be used to assess different technologies in
order to identify the best environmental option; alternatively, it can be used
to provide a scientific basis for developing sound environmental strategies and
policies in government or industry.
Current LCA resources in the Philippines are limited, but in the past
decade De La Salle University – Manila has gradually developed the capacity to
engage in scientific research, technical consultancy and training in this
field. A description of some current
projects undertaken by the LCA research group is given.
Key Words: Life-cycle
assessment (LCA), environmental management, decision support
1. Introduction
Development of truly
effective environmental policies and strategies requires proper scientific
basis. Life cycle assessment (LCA) is a
framework and methodology for the identification of environmentally friendly products
or processes. It is characterized by
the analysis of cumulative environmental impacts over extended system
boundaries. While conventional
environmental assessment techniques focus only on either manufacturing
processes or end-of-life disposal (or reuse), LCA considers the life cycle of a
system, or the entire chain of events and activities that are necessary to
support the product or process (SETAC, 1991; ISO, 1997). This is often called the cradle-to-grave
approach, and has the obvious advantage of revealing potentially significant
but “hidden” environmental impacts.
Instead of focusing attention on large, concentrated, and readily
apparent point sources of impacts – for example, a manufacturing plant – LCA
also takes into account dispersed activities whose cumulative effects may prove
to be critical as well. The life cycle
concept thus gives a more accurate picture of the environmental impacts than
conventional techniques; it evolved over the last three decades from a relatively
vague framework for conducting assessments, into a rigorous set of
internationally standardized guidelines.
2. History
of LCA
The earliest forerunners of LCA were the Resource
And Environmental Profile Analyses (REPAs) of the late 1960s and early
1970s. A series of studies were conducted
by the Midwest Research Institute, and later by the consulting firm Franklin
Associates Ltd., mostly for the private sector. The Coca Cola Company and Mobil Corporation were two of the firms
for which REPA studies were done (Assies, 1993; Curran, 1996). A REPA study of
different beverage packaging systems by Hunt et al (1974) was a typical example
of these LCA predecessors. Interest
continued through the 1980s, with studies by Gaines (1981) and Lundholm and Sundstrom
(1985) being typical of the REPA studies used for policy- and
decision-making. As the term REPA
suggests, these early studies emphasized raw material demands, energy inputs,
and waste generation flows; attempts on more sophisticated analysis through
environmental impact classifications would come later in the evolution of LCA
methodology.
Another early type of LCA
emerged in the late 1970s in the form of net energy analysis (Boustead and
Hancock, 1979). During the global oil
crises of 1973 and 1979, many countries, including the Philippines, the United
States and Brazil, began to explore petroleum substitutes. Bioethanol (ethyl alcohol produced through
the fermentation of carbohydrate biomass) was one of the most extensively
tested fuel; Brazil was particularly successful in its commercialization, and
its ProAlcool program has continued for the past 20-odd years (Moreira
and Goldemberg, 1999). One of the
problems that became apparent was that the production of bioethanol on a
life-cycle basis was highly energy-intensive.
Net energy analysis was used to compare the cumulative energy inputs
into the bioethanol life cycle (including agricultural inputs for feedstock
production) with the energy value of the final product; such a comparison gave
a true indication of the extent to which a substitute fuel displaced
conventional energy sources. Early
studies in the United States found a net energy deficit – more energy was
needed to make the alcohol than could be recovered from its eventual combustion
(Chambers et al, 1979; Lewis, 1980).
Such studies continued to be used for the assessment of bioethanol and
other alternative fuels, with the net
energy approach being favored in North America (Shapouri et al, 1995) and an
alternative energy ratio approach being more common in Europe (Culshaw and
Butler, 1992). Eventually these energy
analysis techniques led to the emergence of specialized LCAs for fuel and
energy systems. These LCAs are now
called Full Fuel Cycle Assessments (FFCAs).
Modern LCA methodology is
rooted in the development of standards through the 1990s. The Society for Environmental Toxicology and
Chemistry (1991) published “A Technical Framework for Life Cycle Assessments,”
the first attempt at an international LCA standard. It explicitly outlined the components of contemporary LCA: goal
definition, inventory assessment, impact assessment, and improvement
analysis. By extending LCA beyond the
mere quantification of material and energy flows (the predominant theme in
REPA, net energy analysis, and other early forms of LCA), SETAC paved the way
for the use of LCA as a comprehensive decision support tool. Similar developments took place some time
later in Northern Europe, particularly in the Scandinavia. In 1995 detailed LCA protocols were
specified in the “Nordic Guidelines on Life Cycle Assessments” (Nordic Council
of Ministers, 1995).
In the late 1990’s, the
International Organisation for Standardisation (ISO) released the ISO 14040
series on LCA as an adjunct to the ISO 14000 Environmental Management
Standards. The series includes
standards for goal and scope definition and inventory assessment (ISO 14041,
1998), impact assessment (ISO 14042, 2000a), and interpretation (ISO 14043,
2000b), as well as a general introductory framework (ISO 14040, 1997). The ISO 14040 series actually bears a strong
resemblance to the original SETAC framework; Azapagic’s review (1999) gives a
comparison between the two LCA standards.
However, because of ISO’s dominant position in the development of international
standards, the ISO 14040 series may eventually supercede the SETAC guidelines
among LCA practitioners.
3. The
Product Life Cycle
The life cycle of a generic industrial product was defined by SETAC
(1991) as being composed of the following stages:
§
Raw Material Acquisition – all activities necessary to extract raw material
and energy inputs from the environment, including the transportation prior to
processing.
§
Processing and Manufacturing – activities needed to convert the raw material and
energy inputs into the desired product.
In practice this stage is often composed of a series of substages with
intermediate products being formed along the processing chain.
§
Distribution and Transportation – shipment of the final product to the end user.
§
Use, Reuse, and Maintenance – utilization of the finished product over its
service life.
§
Recycle – begins after the product has served its initial intended function
and is subsequently recycled within the same product system (closed-loop
recycle) or enters a new product system (open-loop recycle).
§
Waste Management – begins after the product has served its intended function and is
returned to the environment as waste.
The interactions of these
stages with each other and with the external environment are shown in Figure
1. The combined stages constitute the
entire cradle-to-grave system.
Truncation of the chain
yields partial life cycles which in some cases may be sufficient for the
analysis demanded by the study objectives (Todd, 1996). There are three variants of partial LCAs:
§
Cradle to Gate – analysis upstream of point of truncation.
§
Gate to Grave – analysis downstream of point of truncation.
§
Gate to Gate – analysis between two points of truncation.
Figure 1 Stages in the Life Cycle of a Product (SETAC, 1991)
4. Key
Features of LCA
5. Components
of LCA
Early LCA-type studies
focused exclusively on quantifying material and energy flows. The emergence of modern LCA standards in the
1990s (SETAC, 1991; Nordic Council of Ministers, 1995; ISO, 1997; ISO, 1998)
was characterized by an increase in the level of sophistication of the general
life-cycle concept, which has now been extended to include four components for
a full LCA. These components are:
§
Goal and Scope Definition – specifies the objective of the assessment as well
as the assumptions under which all subsequent analysis is done. LCA objectives can be classified broadly
into system improvement studies, in which the goal is to identify opportunities
for reducing the environmental effects of an existing system or process, and
comparative studies, in which the intent is to select an optimal product of
process from a number of predetermined alternatives. Scope definition involves specifying system boundaries,
functional unit, allocation assumptions, inventory parameters, and impact
categories that will be used. Depending
on the scope and objectives, it may not be necessary for an LCA to have all
four components. In some cases, for
example, a simple inventory assessment may be sufficient.
§
Inventory Analysis – involves the quantification of environmentally relevant material and
energy flows of a system using various sources of data. Essentially, an accounting of system inputs
and outputs is performed. The data used
may come from a variety of sources, including direct measurements, theoretical
material and energy balances, and statistics from databases and publications.
§
Impact Assessment – analyzes and compares the environmental burdens associated with the
material and energy flows determined in the previous phase. The conventional approach is to classify the
inventory flows into specific impact categories (e.g., global warming, resource
depletion, ecotoxicity). Normalization
and weighting (or valuation) of the impacts is also included in this stage. If necessary, the individual impacts can then
be aggregated into a single composite environmental index.
§
Interpretation (ISO, 2000b) or Improvement Assessment (SETAC, 1991) – utilizes
the results of the preceding stages to meet the specified objectives. Typically this phase will generate a decision
or plan of action. For diagnostic LCAs,
the data is used to identify critical segments or “hot spots” in the life cycle
which contribute disproportionately to the total system environmental impact. These problem areas can then be eliminated
or reduced through system modifications.
In the case of comparative LCAs, the competing system life cycles are
ranked based on environmental performance and the optimal alternative is
selected.
Azapagic (1999) points out the strong similarities
between the SETAC and ISO standards.
Aside from terminology, the principal difference lies in the fourth
component of LCA. In the SETAC
framework, the principal focus of this final improvement assessment stage is to
identify opportunities for improving environmental performance. Under the ISO framework, the fourth phase is
called interpretation and is extended to include sensitivity analysis and final
recommendations.
The interactions among the four LCA components are
shown schematically in Figure 2.
Figure 2 Interactions Among LCA Components (SETAC, 1991)
6. Uses
of LCA
LCA is one of many
environmental management tools (ISO, 1997).
It can be used by governments, private firms, consumer organizations,
and environmental groups as a decision support tool (Wenzel et al, 1997; Krozer
and Vis, 1998; Field and Ehrenfeld, 1999).
The scope of the decisions covered by LCA ranges from broad management
and policy choices to specific selection of product or process characteristics
during design. Also, LCA may be applied
prospectively or retrospectively (Ludwig, 1997).
LCA applications (ISO, 1997) can be classified into
the following:
§
Indentification
of opportunities to improve the environmental aspects of products at various
points in their life cycles.
§
Decision-making
in industry, government, and non-government organizations (NGOs).
§
Selection
of indicators of environmental performance and measurement procedures.
§
Marketing,
including ecolabelling and improvement of corporate image.
Table 2 lists LCA
applications based on broad objectives of “focus” and “choice” as suggested by
Wenzel et al (1997). “Focus” refers to
a stand-alone diagnostic LCA to
identify points of interest within a single life cycle system, whereas “choice”
refers to comparative LCAs of competing alternatives with the ultimate
objective of ranking and selection. They also give a more detailed description
of the uses of LCA in the private and public sectors as well as NGOs. LCA applications grouped according to users
are given in Table 3.
Table 2 LCA Applications According to Objectives (Wenzel et al, 1997)
|
Objective |
Application |
Support
for Decision |
|
Diagnosis |
Product Development |
Background for environmental specifications; design
strategies, principles and rules. |
|
Ecolabelling |
Identifies important environmental proerties for the
product category. |
|
|
Community Action Plans |
Identifies environmentally important product groups. |
|
|
Selection |
Product Development |
On-going identification of the best choices from
alternative solutions. |
|
Cleaner Technology |
Identifies the best available technology by means of LCA. |
|
|
Community Action Plans |
Identifies the best community strategy for a certain
problem or product. |
|
|
Consumer Information |
Documents potential environmental impacts from a certain
product |
Table 3 LCA Applications According to User Type (Wenzel et al, 1997)
|
LCA User |
Application |
Example |
|
Government |
Community Action Plans |
Incineration versus Recycling |
|
Public Transport Systems |
||
|
Environmentally Conscious Public Purchase |
Cars, Office Supplies |
|
|
Consumer Information |
Ecolabels & Standards |
|
|
Company |
Establish Environmental Focus |
Identification of Areas of Improvement |
|
Product-Oriented Environmental Policy |
||
|
Environmental Management |
||
|
Design Choices |
Concept Selection |
|
|
Component Selection |
||
|
Material Selection |
||
|
Process Selection |
||
|
Environmental Documentation |
ISO 14000 Certification, Ecolabels |
Although LCA is often utilized as an assessment tool
for management-level policy formulation, recently there has been more emphasis
on its use as a process or product design aid at the technical level (Azapagic,
1999). This approach involves the use
of LCA for:
§
Process Technology Selection – determination of the best pathway by which a
specified product or service can be provided, through selection from a number
of competing alternative processes.
This application extends the practice of choosing the Best Practicable
Environmental Option (BPEO) to incorporate life-cycle considerations.
§
Process Optimization – extends conventional process optimization
practice, including mathematical programming techniques, to include objective
functions that reflect environmental life-cycle considerations. This application also includes improvement
of existing processes through retrofits and modifications.
§
Process Design – extension of DFE methodology to a life-cycle basis, under the
emerging framework of life cycle process design (LCPD). Product and process design are integrated;
this key feature allows more flexibility in achieving full environmental benefits.
§
Product Development – selection of environmentally sound features and components of an
industrial or commercial commodity.
Potential applications include screening of environmentally sound
packaging and raw materials.
7. Survey
of LCA Applications
LCA has been used extensively in Europe and North America by government
and business organizations. These
assessments have been used both for streamlining day-to-day operations and for
defining long-term research and development priorities. Typical success stories include:
§
Use
of LCA by the United States Department of Defense to determine purchasing
policies for office supplies, particularly the identification of
environment-friendly paper (Goidel and McKiel, 1996).
§
Development
of the GREET software model by a research division of the United States
Department of Energy for assessing the environmental benefits of different
technological options for road vehicles (Wang, 1996). An updated version of this program was recently used by the
Global Alternative Propulsion Center (GAPC) of General Motors Corporation to
determine R&D priorities for the development of the next generation of
motor vehicles (Wang, 2001; General Motors Corporation et al., 2001).
Table 4 lists other firms and government agencies that have
successfully utilized LCA-based methods, as documented in Allen (1996), van
Berkel et al. (1997), Graedel (1998) and Verschoor and Reijndrs (1999).
Table 4 Recent Users of LCA and Related Methods
|
Type of Organization |
Name of
Organization |
|
Government Agency |
UK Department of Trade & Industry US Department of Energy US Department of Agriculture US Environmental Protection Agency US Department of Defense |
|
Private Firm |
AT&T Procter & Gamble General Motors Corp. Volvo Credit Suisse The Body Shop BP Amoco IBM Motorola Dow Chemical Nestle Coca-Cola TetraPak Scott Paper ExxonMobil Shell Hoechst Monsanto
|
8. LCA
Research in De La Salle University – Manila
De La Salle University – Manila has established
itself as the leading Philippine institution in the field of LCA, thanks in
part to links with the University of Portsmouth of the UK dating back to the
early 1990s. A variety of activities
have been undertaken during this period,
such as: