A method for operating a combined cycle power plant (CCPP) and improving a part load operation of the CCPP is provided. The CCPP may include at least a gas turbine, a heat recovery steam generator (HRSG) located downstream of the gas turbine, a main steam turbine, and a supercritical steam turbine. The HRSG may include a low pressure steam system, an intermediate pressure steam system, and a high pressure steam system. To improve the part load efficiency of the CCPP, a base load operation of the CCPP may be initiated with supercritical pressure, via the supercritical steam turbine, such that the efficiency impact resulting from the part load operation is reduced.