diff --git a/include/cantera/thermo/HMWSoln.h b/include/cantera/thermo/HMWSoln.h
index 0768de34cb..62ba66723c 100644
--- a/include/cantera/thermo/HMWSoln.h
+++ b/include/cantera/thermo/HMWSoln.h
@@ -821,6 +821,7 @@ class HMWSoln : public MolalityVPSSTP
      */
     virtual double relative_molal_enthalpy() const;
 
+    double intEnergy_mole() const override;
     double cv_mole() const override;
 
     //! @}
diff --git a/include/cantera/thermo/IdealMolalSoln.h b/include/cantera/thermo/IdealMolalSoln.h
index 49445ba31a..7c069806cb 100644
--- a/include/cantera/thermo/IdealMolalSoln.h
+++ b/include/cantera/thermo/IdealMolalSoln.h
@@ -86,22 +86,6 @@ class IdealMolalSoln : public MolalityVPSSTP
         return true;
     }
 
-    //! @name  Molar Thermodynamic Properties of the Solution
-    //! @{
-
-    //! Molar internal energy of the solution: Units: J/kmol.
-    /*!
-     * Returns the amount of internal energy per mole of solution. For an ideal
-     * molal solution,
-     * @f[
-     * \bar{u}(T, P, X_k) = \sum_k X_k \bar{u}_k(T)
-     * @f]
-     * The formula is written in terms of the partial molar internal energy.
-     * @f$ \bar{u}_k(T, p, m_k) @f$.
-     */
-    double intEnergy_mole() const override;
-
-    //! @}
     //! @name Mechanical Equation of State Properties
     //!
     //! In this equation of state implementation, the density is a function only
diff --git a/include/cantera/thermo/IdealSolidSolnPhase.h b/include/cantera/thermo/IdealSolidSolnPhase.h
index c222c05ce7..770f96a75e 100644
--- a/include/cantera/thermo/IdealSolidSolnPhase.h
+++ b/include/cantera/thermo/IdealSolidSolnPhase.h
@@ -70,6 +70,8 @@ class IdealSolidSolnPhase : public ThermoPhase
     //! @name Molar Thermodynamic Properties of the Solution
     //! @{
 
+    double intEnergy_mole() const override;
+
     /**
      * Molar entropy of the solution. Units: J/kmol/K. For an ideal, constant
      * partial molar volume solution mixture with pure species phases which
diff --git a/include/cantera/thermo/LatticePhase.h b/include/cantera/thermo/LatticePhase.h
index 8b8733d381..17e1987cda 100644
--- a/include/cantera/thermo/LatticePhase.h
+++ b/include/cantera/thermo/LatticePhase.h
@@ -222,6 +222,8 @@ class LatticePhase : public ThermoPhase
      */
     double enthalpy_mole() const override;
 
+    double intEnergy_mole() const override;
+
     //! Molar entropy of the solution. Units: J/kmol/K
     /*!
      * For an ideal, constant partial molar volume solution mixture with
diff --git a/include/cantera/thermo/MargulesVPSSTP.h b/include/cantera/thermo/MargulesVPSSTP.h
index 195ef4483b..4d6c1dacea 100644
--- a/include/cantera/thermo/MargulesVPSSTP.h
+++ b/include/cantera/thermo/MargulesVPSSTP.h
@@ -230,6 +230,7 @@ class MargulesVPSSTP : public GibbsExcessVPSSTP
     //! @name  Molar Thermodynamic Properties
     //! @{
 
+    double intEnergy_mole() const override;
     double cv_mole() const override;
 
     //! @}
diff --git a/include/cantera/thermo/MixtureFugacityTP.h b/include/cantera/thermo/MixtureFugacityTP.h
index 76431d7d95..2d070602b3 100644
--- a/include/cantera/thermo/MixtureFugacityTP.h
+++ b/include/cantera/thermo/MixtureFugacityTP.h
@@ -111,6 +111,7 @@ class MixtureFugacityTP : public ThermoPhase
     //! @{
 
     double enthalpy_mole() const override;
+    double intEnergy_mole() const override;
     double entropy_mole() const override;
 
     //! @}
diff --git a/include/cantera/thermo/ThermoPhase.h b/include/cantera/thermo/ThermoPhase.h
index c89e7aa5b8..6a691a92a7 100644
--- a/include/cantera/thermo/ThermoPhase.h
+++ b/include/cantera/thermo/ThermoPhase.h
@@ -539,8 +539,19 @@ class ThermoPhase : public Phase
     }
 
     //! Molar internal energy. Units: J/kmol.
+    /*!
+     * Returns the amount of internal energy per mole of solution. For an ideal
+     * molal solution,
+     * @f[
+     * \bar{u}(T, P, X_k) = \sum_k X_k \bar{u}_k(T)
+     * @f]
+     * The formula is written in terms of the partial molar internal energy.
+     * @f$ \bar{u}_k(T, p, m_k) @f$.
+     * @relates getPartialMolarIntEnergies
+     */
     virtual double intEnergy_mole() const {
-        return enthalpy_mole() - pressure()* molarVolume();
+        getPartialMolarIntEnergies(m_tmpV.data());
+        return mean_X(m_tmpV);
     }
 
     //! Molar entropy. Units: J/kmol/K.
diff --git a/src/thermo/HMWSoln.cpp b/src/thermo/HMWSoln.cpp
index d37c6efc68..7e1885663c 100644
--- a/src/thermo/HMWSoln.cpp
+++ b/src/thermo/HMWSoln.cpp
@@ -103,6 +103,11 @@ double HMWSoln::relative_molal_enthalpy() const
     return L / xuse;
 }
 
+double HMWSoln::intEnergy_mole() const
+{
+    return enthalpy_mole() - pressure() * molarVolume();
+}
+
 double HMWSoln::cv_mole() const
 {
     double kappa_t = isothermalCompressibility();
diff --git a/src/thermo/IdealMolalSoln.cpp b/src/thermo/IdealMolalSoln.cpp
index 59623f930a..00c5963424 100644
--- a/src/thermo/IdealMolalSoln.cpp
+++ b/src/thermo/IdealMolalSoln.cpp
@@ -45,12 +45,6 @@ IdealMolalSoln::IdealMolalSoln(const string& inputFile, const string& id_) :
     initThermoFile(inputFile, id_);
 }
 
-double IdealMolalSoln::intEnergy_mole() const
-{
-    getPartialMolarIntEnergies(m_tmpV.data());
-    return mean_X(m_tmpV);
-}
-
 // ------- Mechanical Equation of State Properties ------------------------
 
 double IdealMolalSoln::isothermalCompressibility() const
diff --git a/src/thermo/IdealSolidSolnPhase.cpp b/src/thermo/IdealSolidSolnPhase.cpp
index d4240f32c7..276757263a 100644
--- a/src/thermo/IdealSolidSolnPhase.cpp
+++ b/src/thermo/IdealSolidSolnPhase.cpp
@@ -24,6 +24,11 @@ IdealSolidSolnPhase::IdealSolidSolnPhase(const string& inputFile, const string&
 
 // Molar Thermodynamic Properties of the Solution
 
+double IdealSolidSolnPhase::intEnergy_mole() const
+{
+    return enthalpy_mole() - pressure() * molarVolume();
+}
+
 double IdealSolidSolnPhase::entropy_mole() const
 {
     return GasConstant * (mean_X(entropy_R_ref()) - sum_xlogx());
diff --git a/src/thermo/LatticePhase.cpp b/src/thermo/LatticePhase.cpp
index 4061291d88..c88778d4bb 100644
--- a/src/thermo/LatticePhase.cpp
+++ b/src/thermo/LatticePhase.cpp
@@ -34,6 +34,11 @@ double LatticePhase::entropy_mole() const
     return GasConstant * (mean_X(entropy_R_ref()) - sum_xlogx());
 }
 
+double LatticePhase::intEnergy_mole() const
+{
+    return enthalpy_mole() - pressure() * molarVolume();
+}
+
 double LatticePhase::gibbs_mole() const {
     return enthalpy_mole() - temperature() * entropy_mole();
 }
diff --git a/src/thermo/MargulesVPSSTP.cpp b/src/thermo/MargulesVPSSTP.cpp
index c9bfa73728..b22ff3d965 100644
--- a/src/thermo/MargulesVPSSTP.cpp
+++ b/src/thermo/MargulesVPSSTP.cpp
@@ -49,6 +49,11 @@ void MargulesVPSSTP::getChemPotentials(double* mu) const
     }
 }
 
+double MargulesVPSSTP::intEnergy_mole() const
+{
+    return enthalpy_mole() - pressure() * molarVolume();
+}
+
 double MargulesVPSSTP::cv_mole() const
 {
     return cp_mole() - GasConstant;
diff --git a/src/thermo/MixtureFugacityTP.cpp b/src/thermo/MixtureFugacityTP.cpp
index 39c1697d95..1f486cfb0b 100644
--- a/src/thermo/MixtureFugacityTP.cpp
+++ b/src/thermo/MixtureFugacityTP.cpp
@@ -47,6 +47,12 @@ double MixtureFugacityTP::enthalpy_mole() const
 }
 
 
+double MixtureFugacityTP::intEnergy_mole() const
+{
+    return enthalpy_mole() - pressure() * molarVolume();
+}
+
+
 double MixtureFugacityTP::entropy_mole() const
 {
     double s_ideal = GasConstant * (mean_X(m_s0_R) - sum_xlogx()