Identifying all these environmental costs is difficult and time consuming. Raw materials mined or grown, land uses, noise generation, releases of pollutants to the air, water, or soil, and all other ecological costs are evaluated and compared. The analysis must include proportional life-cycle costs of products that go into the manufacture or use of each product, such as catalysts needed during the production of the plastic polymer. For plastic bottles, the assessment would include raw oil production, oil refining, proportional costs of recycled content, polymer production, bottle production, bottling, transport, and disposal or recycling. For aluminum, the assessment would include mining bauxite, production of aluminum (including proportional costs of recycled content), production of cans, filling the cans, transport, and disposal or recycling. For glass bottles, this would include mining of silica and other minerals, proportional costs of recycled content, bottle production, bottling, transport, and disposal or recycling. Cradle-to cradle assessments for all three options must be performed. To illustrate the life-cycle assessment process, consider a comparison of the environmental costs of beverage packaging made of glass, aluminum, and plastic. Unfortunately, only about half of the aluminum cans produced in the United States are recycled, so there's still some "grave" in aluminum can production.įigure 7-Building materials that are no longer needed for theirĪre recycled or reused in a cradle-to-cradle life cycle.
Manufacturing new cans from recycled cans cuts energy use by 95 percent, making aluminum cans a cradle-to-cradle product. Aluminum production is extremely energy intensive, but aluminum is fully recyclable no matter how many times it has already been recycled. An example of a cradle-to-cradle product is an aluminum beverage can. In these cases, the cycle is often referred to as "cradle-to-cradle" ( figure 7). Some products can be partly or completely reused or remanufactured into new products after they have served their original purpose. Materials are used once and then discarded. The sum of the cradle-to-grave environmental costs is the life-cycle environmental cost of the product.įigure 6-In a cradle-to-grave life cycle, building This is sometimes referred to as a "cradle-to-grave" ( figure 6) assessment. This starts with production of raw materials and includes manufacture, distribution, use, disposal, transportation, and the energy used by the product, process, structure, or activity. In this context, the term "life cycle" means the assessment considers everything that goes into or is produced as a result of the product or service. While a life-cycle cost analysis is a financial tool, a life-cycle assessment evaluates the environmental costs associated with a product, process, structure, or activity by identifying energy and materials used and wastes released to the environment.
Life-Cycle Cost Analysis for Buildings Is Easier Than You Thought Life-Cycle Assessments Can Help You Make Sustainable Choices