Additionally, ORCs eliminate the need for full-time plant operators because they operate at lower pressures and do not need water chemistry maintenance. However, working fluid cost, decomposition, temperature limits are an organic Rankine cycle's primary disadvantages.

Current interest in the Rankine engine stems from its potential to have low emissions and its ability (because it is an external-combustion engine) to use a variety of fuels. The disadvantages of the engine are its complexity and low efficiency.

The efficiency of the Rankine cycle is limited by the high heat of vaporization of the working fluid. Unless the pressure and temperature reach supercritical levels in the boiler, the temperature range over which the cycle can operate is quite small.

ORC's can recover heat from waste streams at lower temperatures than is possible with conventional steam Rankine systems, and because ORCs operate at relatively low pressure, they can operate unattended and fully automated in most locations.