A direct field cost estimate was developed for each absorber design. These cost estimates are summarized in Table . Not every estimate explicitly listed costs for piping, instrumentation, and foundations associated with the respective absorbers. Therefore, these costs are excluded from the "cost of scope". The scope included in these costs is the absorber vessel itself including column internals and external structural steel and access platforms. All designs use stainless steel, mostly grades 304 or 304L.