The aim of the article is to reach increased understanding of the potential obstacles and opportunities for industry/energy-company collaborations. This is achieved through exploring a pioneering collaboration regarding waste heat from a steelworks to a local district heating system in northern Sweden that was established in the 1970s. With a historical qualitative approach and focus on the long-term and dynamic explanatory factors behind the collaboration, the article complements previous studies typically focusing on barriers/drivers at the end of the process from idea to actual waste heat supplies (e.g., the allocation of costs among parties). From a long-term perspective, concerns over the actual waste heat supplies were found to be protracted and more critical. Hence, although the collaboration from start rested on firm beliefs of sufficient supplies, concerns over actual supplies remained critical throughout the 11-year long process. The article suggests that: a) market fluctuations and the industrial company's continuous strive for profit maximization tend to be underestimated in previous literature on obstacles to waste heat supplies; and b) targeted government subsidies could be an essential policy tool for promoting future waste heat collaborations, in turn resting on a mix of societal rationales (e.g., energy security, climate mitigation, regional development, etc.).