As seen from Figure for the lower capacities, the implemented compressor equipment cost model matches OEM data for integrally geared compressors quite well. From 1.5 to 12 MMtonnes/year, the over-prediction of the model increases somewhat, suggesting that the economy of scale built into the model is possibly slightly pessimistic. For the higher flows of 6 and 12 MMtonnes/year, Figure . Calculated equipment cost compared to OEM data for compression of CO 2 using integrally geared compressors. OEM data is sourced from ref. . All cost are on a year 2010 basis (CEPCI=550.8). Stainless steel has been assumed for compressor casing material.