Various embodiments include apparatuses and related methods for determining the enthalpy of steam. In some embodiments, an apparatus includes: an extraction conduit fluidly connected with a steam turbine section, the extraction conduit for obtaining wet steam from the steam turbine section; a mixing chamber fluidly connected with the extraction conduit; an injector fluidly connected with the mixing chamber, the injector for providing dry steam to the mixing chamber for mixing with the wet steam from the steam turbine section to produce a sample mixture; and an enthalpy detection system fluidly connected with the mixing chamber, the enthalpy detection system configured to determine an enthalpy of the sample mixture.