Southwest Research Institute (SwRI) is developing novel compression technology concepts to reduce carbon dioxide (CO2) compression power requirements by 10 percent compared to conventional compressor designs. The basic concept is a semi-isothermal compression process where the CO2 is continually cooled using an internal cooling jacket rather than using conventional interstage cooling. The project includes thermodynamic testing (Phase I), prototype testing (Phase II), and a full-scale demonstration of a multistage, internally cooled diaphragm pilot test (Phase III).