For historical reasons, many large industrial sites have their own power generation units, either because the site was isolated when it was built or because the local network was not reliable enough to ensure regular production. This can apply to energy-intensive industries like refineries or LNG plants in the Oil & Gas sector, but also to mining plants, metal industries and chemical plants. These generation assets are usually operated in a suboptimal way, the only concern being the safety of the process. The focus of this work is to determine how industrial plant operators can make optimal use of these assets, considering interactions with the electricity markets. Based on the mathematical description of this optimization problem, a model achieving a double target is introduced. First, to develop a standard architecture that can be easily translated from one case to another. Then, to assess the maximum expected savings and the induced strategy. This model is applied to a refinery case study, where expected earnings are as much as epsilon 8 M per year and account for 1% of turnover. The figures obtained show that this is a relevant business concept. Following this trend, the potential to implement Waste Heat Recovery in energy-intensive cement plants is considered. (C) 2016 Elsevier Ltd. All rights reserved.