A. Definition

Life Cycle Assessment (LCA) identifies, quantifies and evaluates the environmental impacts (inputs and outputs) of a product, service or activity, from cradle to grave. That is, the environmental impacts of all phases of the product's life are assessed, from the time materials are extracted through manufacture, transportation, storage, use, recovery, reuse and disposal.

B. Main Features

LCA is a decision making tool. It acknowledges that all phases of a product's life, from cradle to grave, have an impact on the environment and these impacts can be quantified and compared.

Industry and consumers frequently use LCA to compare designs, products or services that perform the same function. Comparisons are made in terms of environmental impact. Other tools and processes also use LCA, such as eco-labels, setting environmental regulations or policies, writing environmental statements, benchmarking, identifying areas for improvement and collecting environmental data. The use of LCA encourages preventative and proactive environmental management rather than reactive end-of-pipe approaches.

LCA can be a very involved and lengthy process. However, the basic steps in LCA are:

• Goal and scope definition - this step defines the purpose of the LCA, identifies assumptions and boundaries and defines the scope (that is, what processes, elements and activities associated with the product/process/activity will be assessed).
• Analysis - the impacts of energy, materials, emissions, etc are identified, classified and quantified. An inventory table listing all environmental impacts is one outcome of this process.
• Assessment - the environmental impacts of the product/process/activity are assessed.
• Interpretation/evaluation - the results are interpreted or evaluated. Opportunities for environmental improvement identified and value judgments made. Products/services/activities are compared.

Several other sustainability concepts have arisen from LCA. Life cycle costing (LCC) examines environmental costs and is applicable to environmental accounting and budgeting. Streamlined LCA is a leaner approach to LCA, cutting costs and time involved in conducting a LCA. Life cycle inventory (LCI) looks at the inventory stage of LCA. Life cycle management (LCM) integrates life cycle principles into business and management structures, rather than just conducting a once off LCA.

There is much debate about the validity and usefulness of LCA. However, used correctly, LCA provides meaningful results to aid decision-making.

C. Organizational Proponent

LCA is a descendent of energy modeling studies of the 1960s and 1970s. These studies were developed and expanded to become LCA in the 1990s.

D. Case Studies and Examples

1. Wind Farm Materials
Denmark conducted a LCA on the energy and emissions resulting from the manufacture, production and transport of different materials required for the construction of offshore and land-based wind farms. The study found that the energy payback time for offshore wind farms was 0.39 years. For land-based wind farms the energy payback time was 0.26 years. The study noted that 94% of materials used could be recycled. Carbon dioxide emissions were found to account for 68 - 93% of external costs for land-based wind farms and 99% for offshore wind farms.

E. Target Sectors / Stakeholders

The primary stakeholders of LCA are industry, standards bodies, research organisations, non- government organisations and governments. Suppliers, contractors, the community, and businesses may be affected by the outcomes of and LCA.

F. Scale of Operation

LCA is applicable world-wide but is best implemented at a process or activity level.

G. Links

• Global Development Research Centre - LCA for Cities
• Lifecycle Assessment Research Centre
• International Standards Organisation (ISO)
• Pre Consultants - Life Cycle Assessment
• USA EPA - Life Cycle Assessment
• Life Cycle Journals
• Ecocycle
• UNEP and SETAC Life Cycle Initiative
• L. Schleisner 2000 Life cycle assessment of a wind farm and related externalities Renewable Energy Volume 20, Issue 3