Avoided burden is an approach used in Life Cycle Assessment

Life cycle assessment

A life-cycle assessment is a technique to assess environmental impacts associated with all the stages of a product's life from-cradle-to-grave A life-cycle assessment (LCA, also known as life-cycle analysis, ecobalance, and cradle-to-grave analysis) is a technique to assess environmental impacts...

 (LCA), especially in the context of allocating environmental burden in the presence of recycling

Recycling

Recycling is processing used materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution and water pollution by reducing the need for "conventional" waste disposal, and lower greenhouse...

 or reuse

Reuse

To reuse is to use an item more than once. This includes conventional reuse where the item is used again for the same function, and new-life reuse where it is used for a different function. In contrast, recycling is the breaking down of the used item into raw materials which are used to make new...

. When determining the overall environmental impact of a product, the product is given "credit" for the potential recycled material included. For instance, PET

Polyethylene terephthalate

Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...

 bottles may be given environmental credit for the PET they contain, as this material will eventually be recycled back into further PET products. This credit is termed "avoided burden" because it refers to the impact of virgin material production that is avoided by the use of recycled material.

Material Displacement

The extent to which recycled material displaces production of virgin material of a similar or different type is the subject of current research. In case studies, practitioners typically utilize heuristic

Heuristic

Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...

, arbitrary rules, such as assigning 100%, 50%, or 0% displacement of virgin material by recycled material. However, accurate information on the displacement rates of various materials is largely unknown. This information is important to LCA practitioners, as it can often tip the balance between two compared alternative products or materials.

Calculation

Although the calculation of avoided burden is not without some degree of subjectivity, it is usually calculated as follows:

Avoided Burden = (Material Recycling Rate) × (Functional Unit) × [(Impact of Virgin Production) − (Impact of Recycling)]