By some of the experimental prototypes, it’s something like 2/3 of the CO2 absorption is just the power to run it and the remaining third is removing extant CO2. People here are overly skeptical about the capabilities as a reaction to liberal media’s over enthusiasm, which prevents finding the real dunks:

• current experimental CO2 capture uses quaternary ammonia, which smells like rotting fish and will prevent DAC systems from being installed in population centers (or at least near rich people)
• the proposed site for this is in Wyoming, where all of those industrial emissions definitely come from