NOVELTY - The method involves providing a double-flow steam turbine including a steam turbine stage, and providing two sets of paired nozzle assemblies (22, 24)/blade assemblies for the turbine stage. A steam condition at a steam source i.e. geothermal well, is determined. The sets of paired nozzle/blade assemblies are selected with reference to the steam condition at the steam source. The selected nozzle assemblies are installed in a diaphragm gap, and the selected blade assemblies are installed on a rotor to effect an optimized operation of the steam turbine with reference to the steam condition.    USE - Method for providing a nozzle/blade configuration to accommodate different steam conditions from a steam source i.e. geothermal well, for supplying steam to a double-flow steam turbine.    ADVANTAGE - The selected nozzle assemblies are installed in the diaphragm gap, and the selected blade assemblies are installed on the rotor to effect optimized operation of the steam turbine with reference to the steam condition, thus improving thermodynamic efficiency of the turbine over the life of a geothermal power plant. The method permits greater flexibility in design of the turbine and shortens delivery cycle for new turbine installations. The method eliminates requirement of complete information on well conditions before proceeding to the design and manufacture of the turbine. The method maintains efficiency of the turbine with changing well conditions while avoiding changes to structurally large components such as rotor, thus minimizing or reducing cost of implementing configuration changes within the turbine.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a method for changing efficiency of a steam turbine    (2) a system for providing a nozzle/blade configuration to accommodate different steam conditions.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a portion of a diaphragm structure.    Nozzle assemblies (22, 24)    Nozzle passages (28, 30)    Outer block (50)    Outer groove (70)    Inner groove (72)