Industrial symbiosis, as part of the emerging field of industrial ecology, requires attention to the flow of materials and energy through local, regional and national economies.

It engages traditionally separate industries and other organisations in a collective approach to add competitive advantage involving physical exchange of materials, energy, water and/or by-products together with collaboration on the shared use of assets, logistics and expertise.

The keys to industrial symbiosis are collaboration, the synergistic possibilities offered by relative geographical proximity and a demand led approach.

Definition modified by Dr Marian Chertow (2000, Yale University)

Historically, it was considered that for industrial symbiosis to work effectively the companies involved must be linked by close geographic proximity. This is no longer the case; although low value/grade materials and heat are restricted by proximity constraints, higher value synergies have no such restrictions.

Another misconception is that industrial symbiosis creates synergies involving a simple bi-lateral movement of materials, water and energy. In reality, the process can be much more complex; by having a regionally delivered but linked national programme, business problems identified in one region can have solutions developed in a second and benefits delivered in a third.

What all synergies have in common, is that they generate cost reductions and new sales for the companies involved, as well as creating significant environmental benefits such as reduced landfill and greenhouse gases. The economic activity generated also has further social benefits with the creation of new businesses and jobs.