The USA Environmental Protection Agency is one of the biggest regulators of green engineering in the world. They have set definitions and principles on the matter:

Green engineering is the design, commercialization, and use of processes and products, which are feasible and economical while minimizing 1) generation of pollution at the source and 2) risk to human health and the environment. Green engineering embraces the concept that decisions to protect human health and the environment can have the greatest impact and cost effectiveness when applied early to the design and development phase of a process or product.

Principles of Green Engineering

• Engineer processes and products holistically, use systems analysis, and integrate environmental impact assessment tools.

• Conserve and improve natural ecosystems while protecting human health and well-being.

• Use life-cycle thinking in all engineering activities.

• Ensure that all material and energy inputs and outputs are as inherently safe and benign as possible.

• Minimize depletion of natural resources.

• Strive to prevent waste.

• Develop and apply engineering solutions, while being cognizant of local geography, aspirations, and cultures.

• Create engineering solutions beyond current or dominant technologies improve, innovate, and invent (technologies) to achieve sustainability.

• Actively engage communities and stakeholders in development of engineering solutions.