The ever-increasing volume of generated waste and its associated environmental impact underlines the pressing need for sustainable and cost-effective utilization solutions such as waste-to-energy coupled with carbon capture. Here chemical-looping combustion (CLC), a potentially highly efficient combustion process with intrinsic CO2 capture, stands out as a promising option. However, to enable the industrial application of CLC, comprehensive large-scale pilot evaluations are necessary. This study aims to address this need by providing novel insights into the practical application of CLC technology utilizing waste as fuel under realistic operational conditions across two large CLC pilot units at SINTEF Energy and TU Darmstadt. During more than 24 hours of operation employing waste as feedstock at 150 kWth scale, typically employed key performance indicators have been evaluated. These metrics include oxygen demand, measured at approximately 30%, and carbon capture efficiency exceeding 90%. Hereby, special emphasis is placed on analyzing their interaction with crucial operational parameters such as reactor temperatures, inventories, and oxygen carrier circulation rate. Preliminary assessments indicate the anticipated positive impact of elevated temperatures and inventories within the fuel reactor. On the other hand, the observed impact of oxygen carrier circulation on overall performance is inconclusive, potentially due to the continuously high oxygen-carrier-to-fuel-ratio throughout operation. Building upon these encouraging results, aligned tests at 1 MWth scale are conducted in Darmstadt using the same waste fuel and similar boundary conditions as in the 150 kWth unit. A comparative analysis of these tests yields valuable insights into the influence of reactor size on process performance.