The cost estimate for Absorber 1 was developed by AECOM. Vessel internals cost (labor and materials) were quoted by a supplier. The material costs for the vessel shell, foundation, and access platforms were based on bulk commodity pricing from a mix of budgetary quotes and historical cost data escalated using producer price indices as of August 2021. Costs for piping and instrumentation associated with the absorber were similarly estimated. The authors of the estimate note that it was developed during 2021, a period of rapidly escalating commodity prices . The "steel" category is primarily made up of labor and material cost for the absorber shell and external structure including access platforms. "Engineered procurements" is primarily the cost of column internals i.e., structured packing with supports, distributors, and collectors.