The energy integration of industrial complexes and urban agglomerations has many benefits in terms of rational energy use and reduced environmental impact, especially during scenarios of supply chain uncertainty and volatile market prices. In fact, the diversification of the energy inputs along with the waste heat upgrading through the implementation of optimal energy integration systems become crucial for defining the new energy pathways towards a sustainable and robust energy security. The enhanced waste heat recovery and residues upgrading may also increase the revenues of the industrial energy systems, as they can be used to supply the energy demands of an urban agglomeration. However, the combinatorial explosion arising from the combination of a large number of energy technologies and the time-varying energy demands calls for the application of a systematic approach capable of identifying the operating conditions and arrangements that minimize the energy resources consumption without impairing the financial feasibility. Thus, in this work, a mixed integer linear problem is solved using OSMOSE platform in order to determine the most profitable arrangement that meets supply and demand profiles of the industrial and urban systems when different energy conversion technologies are considered. More precisely, this analysis sheds light on the relevance of relying on a combination of renewable (e.g. solar, anaerobic digestion, heat pumps) and nonrenewable (e.g. natural gas-based) solutions to supply the time-varying electricity and heating demands of a chemical complex that settles nearby a city, which also has variable energy demands. In this way, the optimal load distribution and the minimum number of components along the lifespan can be achieved. Modeled data of nitrogen fertilizer complexes and typical energy demands of central European zones are also presented. As a result, more stringent environmental and economic scenarios could be bearable in case of shortage of nonrenewable resources, thanks to a higher flexibility achieved using a set of renewable, carbon abatement and methanation technologies.