This report describes a project case example in which the ENERGY CLOUDTM Service, MHI's comprehensive energy solution service using its own AI&IoT technologies, was applied for the improvement of operational efficiency at a Waste to Energy plant. As an approach to solving problems, the optimization was performed through an understanding of the current state from the aspects of both the operator and plant and based on the setting of goals with experts from various fields being involved. As a result, the calorific value of the waste to be incinerated in the future was predicted with an accuracy of 95% or greater, and the operational guidance into which the expertise of experienced operators was incorporated was presented, thereby realizing support for operational decision-making that is quicker and independent of individual skill.