Sustainability Analysis is an assessment of the potential environmental impacts and life cycle costs associated with the development and use of DoD weapons systems, equipment, products, and platforms. Sustainability Analyses can be performed during any stage of the acquisition process to help decision makers better understand the environmental performance of technology alternatives. For more detailed guidance on performing a Sustainability Analysis, see the Sustainability Analysis Guidance: Integrating Sustainability into Acquisition Using Life Cycle Assessment report that is available for download in the Guidance Documents page of this toolkit. 

A Sustainability Analysis incorporates both life cycle assessment (LCA) and life cycle costing (LCC), and the methodology outlined in the Sustainability Analysis Guidance builds on existing LCC and LCA standards. The required input data for a Sustainability Analysis of a given product or system include physical “flow” values (e.g., masses of materials that are consumed and produced by the system under study) as well as system cost information. The outputs of a Sustainability Analysis include the potential environmental impacts of the system under investigation, as well as the total internal and external costs associated with these environmental impacts. 

Sustainability Analysis Steps

The five iterative steps of a Sustainability Analysis are outlined in the figure below. The LCA portion of the Sustainability Analysis is conducted in Steps 2 and 3. In these steps, the life cycle inventory (LCI) is developed for the given system, and the associated impacts are calculated in the Life Cycle Impact Assessment (LCIA). The life cycle costs are then calculated in Step 4 based on the values contained in the LCI. The following sections describe in brief the steps performed when conducting a Sustainability Analysis. For a comprehensive description of these steps with examples, PIs are encouraged to review the Sustainability Analysis Guidance.

Sustainability Analysis Framework

Step 1: Define the Scope

The first step in the analysis is to clearly define the objectives and scope of the study. This includes a definition of the system(s) to be studied, the required system performance, the boundaries of the system (e.g., what specific processes are included in the scope), and any system alternatives that will also be modeled if a comparison is being made. In addition, it is important to define a functional unit that will form the basis of comparison between systems. This basis of comparison includes the functions that a system provides and is the unit on which a system’s input and output values are quantified.

Step 2: Develop a Life Cycle Inventory (LCI)

The next step is to assemble an inventory that contains all of the inputs and outputs associated with any processes that fall within the system boundaries defined in Step 1 of the analysis. The table below lists examples of the types of inputs and outputs that are commonly encountered. 

Example components of a life cycle inventory. The amounts of these inputs and outputs can be reported in several ways, including on a mass or cost basis.

Step 3: Life Cycle Impact Assessment

Once the system’s LCI has been developed, the impacts associated with each input or output contained in the inventory can be calculated using life cycle impact assessment models. These life cycle impacts include values for issue areas such as climate change, aquatic ecotoxicity, and human health. The Defense Input-Output (DIO) database is an example of an impact assessment model and provides impact characterization factors for various products or activities. The DIO database is available for download in the Tools page within this toolkit. A description of several available LCA data sources and software tools can also be found in the Tools page.

Step 4: Life Cycle Cost Estimate

The various costs associated with the system are calculated in Step 4 of the Sustainability Analysis. While the LCA conducted in Steps 2 and 3 of the analysis determines the environmental and health impacts associated with the system under study, the life cycle cost portion assesses the costs of those impacts in a monetary value. External costs (also known as externalities) represent the costs that are borne by society and other non-DoD agencies. These potential financial liabilities are estimated using external cost factors that provide a monetary value per unit of environmental impact. External cost factors can be found in the DIO database along with the impact characterization factors. In addition, the DoD’s internal costs—including direct and indirect costs—are estimated in the Sustainability Analysis. It is also important to understand how future events could drive additional internal costs to the DoD. These costs are referred to as “contingent costs” and are also estimated during the Sustainability Analysis.

Step 5: Synthesize Results

In this final step, the practitioner analyzes and interprets the results of the Sustainability Analysis. This can include a comparison of the sustainability performance of alternative technologies (if applicable), in addition to identifying the life cycle activities that drive impacts and costs for a particular system. During this phase of the analysis the practitioner may conclude that the comparison needs further data or adjusted system boundaries, and the previous steps in the analysis are repeated to incorporate the new information.