Total Footprints Including Dimensionality Reduction Applied to Regional Supply Networks and Regional Total Sites

Resources depletion and air, water and soil pollution cause series of footprints, such as carbon, water, nitrogen, energy, ecological and other. Those footprints originate from unsustainable humans lifestyles over recent decades. Sustainability, comprising of economic, environmental and social parts, and footprints evaluation are therefore becoming increasingly important, and will be even more important in the future due to human population and economic growth in several countries. Since the decisions should have multiple dimensions; economic part and considering several environmental (and social) footprints, which are hardly to combine, it leads to complex multi-objective optimisation problems.

Environmental footprints are usually defined within Life Cycle Assessment framework, and usually consider only direct burdening effects. However, when considering only burdening effects, all systems seem to be unsustainable, even if they provide benefit on the environment. Direct effects should be upgraded with indirect effects, thus providing total effects. Indirect effects measure any unburdening of the environment, due to substitution of harmful with benign products and utilisation of harmful raw materials rather than discarding them.

This contribution highlights the difference between direct and total environmental footprints. Since several environmental footprints should be considered, whose visualisation and interpretation is difficult, a novel method – a Representative Objectives Method – is applied in order to reduce the dimensionality of the problems. It enables the reduction of many-objective problem in multi-objective optimisation to a problem with minimum number of representative objectives. Direct and total environmental footprints including dimensionality reduction are illustrated during two demonstration case studies of: i) regional supply networks, and ii) Regional Total Sites.