ION Engineering’s (ION) advanced solvent is one of the leading second-generation solvent systems currently under development for post-combustion carbon dioxide (CO2) capture. This paper discusses the results obtained at CO2 Technology Centre Mongstad (TCM) in Mongstad, Norway between September 2016 and April 2017, where ION captured over 14,800 tonnes of CO2 throughout the 2,775-hour testing campaign. The testing was done on flue gases from a natural gas-fired combined cycle heat and power facility (CHP) and a residue fluid catalytic cracker (RFCC) from the adjacent Statoil refinery at a scale comparable to 12 MWe. The CO2 concentrations in both flue gas types could be varied using recycle from the stripper or dilution by air. In this work, CO2 concentration settings of between 3.6% and 15.0% were tested. In the TCM plant, which is not optimized for ION’s solvent system, ION achieved a specific reboiler duty (SRD) as low as 3.2 MJ/kg CO2 during the testing at TCM while demonstrating 90% capture efficiency with low emissions and low corrosion. Furthermore, testing showed capturing 98% of the CO2 with ION’s solvent results in only a 10% increase in energy consumption. The results from ION’s campaign at TCM were then used to validate the ION process model in ProTreat® to high accuracy. Subsequent process design optimization shows ION’s solvent is capable of an SRD of less than 2.5 MJ/kg CO2 when incorporating ION’s key process operations. Throughout pilot testing, ION has confirmed its understanding of process improvements and analytics that will enable successful operation of its solvent system at significantly lower L/G circulation rates, packing heights, and regeneration energies than baseline mono-ethanolamine. ION anticipates that the recently completed demonstration at TCM, along with future projects, will facilitate further advancements in the field of CO2 capture and deployment of ION’s technology.