Life-cycle engineering

Life-cycle engineering (LCE) is a sustainability-oriented engineering methodology that takes into account the comprehensive technical, environmental, and economic impacts of decisions within the product life cycle. Alternatively it can be defined as “sustainability-oriented product development activities within the scope of one to several product life cycles.” LCE requires analysis to quantify sustainability, setting appropriate targets for environmental impact. The application of complementary methodologies and technologies enables engineers to apply LCE to fulfill environmental objectives.
LCE was first introduced in the 1980s as a bottom-up engineering approach, and widely adopted in the 1990s as a systematic ‘cradle-to-grave’ approach. The goal of LCE is to find the best possible compromise in product engineering to meet the needs of society while minimizing environmental impacts.  The methodology is closely related to, and overlaps with, life-cycle assessment (LCA) to assess environmental impacts; and life cycle costing (LCC) to assess economic impacts.
The product life cycle is formally defined by ISO 14040 as the “consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal.” Comprehensive life cycle analysis considers both upstream and downstream processes. Upstream processes include "the extraction and production of raw materials and manufacturing," and downstream processes include product disposal (such as recycling or sending waste to landfill). LCE aims to reduce the negative consequences of consumption and ensure a good quality standard of living for future generations, by reducing waste and making product development and engineering processes more efficient and sustainable.
Quantifying Environmental Sustainability.
The first step in completing LCA or LCE is determining the appropriate sustainability thresholds to use as environmental targets for the product system. The proposed Lyngby Framework for LCE is a combined top-down and bottom-up approach for LCE that uses targets based on planetary boundaries. Planetary boundaries can be used to establish limits for the earth’s carrying capacity, defining upper thresholds for the environmental system.
The IPAT equation [Impact = Population (or Volume) x Affluence (or Consumption) x Technology (or Consumption per Unit Produced)] is an accepted method for quantifying the impact of consumption. LCE can be leveraged to manage total environmental impact by addressing the technology effect (single product and product life cycle) and the volume effect (anticipated volume growth as consumption and population increase) of product engineering. Impacts are considered within the context of technical boundary conditions to verify the feasibility of proposed solutions.
Complementary Methodologies and Technologies.
Modern technology provides innovative new opportunities for LCE:
Key Themes in Life Cycle Engineering.
Key themes in LCE are economic, social, environmental and technological. These themes are interlinking and can be influenced by life cycle engineering.