Ecological Rucksack

The total quantity of resources needed to produce a finished product. This can be used to measure the eco-efficiency (called the Rucksack factor in this context) of the manufacturing and production process, as well as indicating the resources pressures exerted on the environment. It is calculated by determining the weight of the finished product and subtracting this from the total material inputs (most of which ends up as waste pollution) needed to create the product, being expressed as ER = MI ¯ PW (or net weight) [ER = Ecological Rucksack; MI = Material Inputs; PW = Product Weight].

An example might be given for the production of a mower weighing 100kg. The total material inputs would include extraction and processing of mineral ore, energy used during the process, water usage, product assembly, air pollution, transportation inputs, and might also, for example, equate to 5,000kg. The ecological rucksack is therefore 4,900kg for the mower, having a rucksack factor of 50:1, (i.e. 5,000kg of material inputs to produce 100kg of product).