Abstract: A steam power plant (100) implementing an improved Rankine cycle (55) wherein steam is injected (82, 96) directly into the energy addition portion of the plant, and the resulting two-phase flow is pressurized by multiphase pumps (88, 98). By relying more heavily on pump pressurization than on a temperature difference for energy injection, plant efficiency is improved over prior art designs since energy injection by pump pressurization results in less irreversibility than energy injection by temperature difference. Direct steam injection and multiphase pumping may be used to bypass the condenser (20), to replace any one or all of the feedwater heaters (24, 32, 34), and/or to provide additional high-pressure energy addition.