Recently, energy need is exponentially increasing in the world while energy sources are decreasing rapidly. Therefore, this issue requires energy sources to be used more efficiently and urges professionals to utilize energy from low temperature energy sources such as waste heat and low temperature renewable sources. In this study, energy and exergy analyses of several clean working fluids are comparatively studied in several organic Rankine cycle configurations. CO2, N2O, and SF6 fluids are compared with the conventional R23 in three ORC configurations, namely the basic ORC cycle, regenerative ORC cycle, and reheat and regenerative ORC cycle, respectively. Effects of various selected system and environmental parameters on the system performances are comprehensively investigated. Even though R23 shows the best energy and exergy performances than those of other investigated working fluids at low-temperature applications, N2O and CO2 provide a clean solution to high GWP (global warming potential) R23 with similar performance characteristics at low and high temperature power generation applications.