Industrial Ecology(IE) is a relatively new field that is based on the ideology of nature. IE uses nature as a “reference” to study resource productivity and environmental burdens of industrial and consumer products and their production and consumption systems.

   Industrial Symbiosis (IS) is a subset of Industrial Ecology with a particular focus on cyclical flows of resources through networks of businesses. One definition is that IS “engages traditionally separate businesses in a collective approach to competitive advantage involving physical exchange of materials, energy, water and/or byproducts. “The keys to IS are collaboration and the synergistic possibilities offered by geographic proximity” [1].

   This paper presents a methodology that aims at developing a method for uncovering IS in the Swedish energy sector. The method is exemplified by district heating and consists of data collection of the occurring resource and energy flows to and from district heating plants in three different Swedish regions. The results show that the method presented in this article can be used in future and more comprehensive "uncovering" studies. The material from a broader, nationwide study is expected to make it possible to develop tools to facilitate the conditions for IS to be developed.