From 9675afa6dfc52a197441ca7bc8aa0ac53f71687c Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Tue, 5 Aug 2025 17:54:06 -0400
Subject: [PATCH 01/19] add multiple startup types

---
 .../pricetaker/unit_commitment.py             | 58 ++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 605ac26699..bc03ef2ab2 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -17,7 +17,7 @@
 capacity limit constraints, and ramping constraints.
 """
 
-from typing import Union
+from typing import Union, Optional
 from pyomo.common.config import ConfigDict, ConfigValue
 from pyomo.environ import Block, Constraint, Var, RangeSet
 from idaes.core.util.config import ConfigurationError, is_in_range
@@ -141,10 +141,28 @@ def startup_shutdown_constraints(
     minimum_up_time: int,
     minimum_down_time: int,
     set_time: RangeSet,
+    startup_transition_time: Optional[dict],
 ):
     """
     Appends startup and shutdown constraints for a given unit/process
+
+    Supports multiples types of startup.
+
+    Args:
+        startup_transition_time (dict): A dictionary with keys as startup types and values are the time of startup transition.
     """
+    # Default one startup type. If provided
+    if startup_transition_time is not None:
+        # at least two types of startup, assume the default one should be at least min_down_time
+        startup_types = {"default": minimum_down_time}
+        for key in startup_transition_time.keys():
+            startup_types[key] = startup_transition_time[key]
+    
+        startup_names = list(startup_types.keys())
+
+        # define the startup type as a binary variable
+        blk.startup_type = pyo.Var(set_time, startup_names, within=pyo.Binary)
+        blk.startup_duration = pyo.Param(startup_names, initialize=startup_types)
 
     @blk.Constraint(set_time)
     def binary_relationship_con(_, t):
@@ -176,6 +194,44 @@ def minimum_down_time_con(_, t):
             <= install_unit - op_blocks[t].op_mode
         )
 
+    @blk.Constraint(set_time)
+    def startup_type_rule(_, t):
+        '''
+        Eq 55 in Ben's paper
+        '''
+        if startup_transition_time is None:
+            return Constraint.Skip
+        
+        return (
+            sum(blk.startup_type[t, k] for k in startup_names) == op_blocks[t].startup
+        )
+
+    if startup_transition_time is not None:
+        # add the startup type constraints for each type of startup
+        for key in startup_types.keys():
+            if key == "default":
+                prev_key = "default"
+                continue
+            
+            def startup_type_rule(_, t, key=key):
+                '''
+                Eq 54 in Ben's paper
+                '''
+                if t < blk.startup_duration[key]:
+                    return Constraint.Skip
+                return (
+                    blk.startup_type[t, key] <= sum(
+                        op_blocks[t - i].shutdown for i in range(
+                            blk.startup_duration[prev_key], blk.startup_duration[key]
+                        )
+                    )
+                )
+            
+            setattr(blk, 
+                    f"startup_type_{key}", 
+                    Constraint(rule=startup_type_rule)
+            )
+
 
 def capacity_limits(
     blk: Block,

From 646ef8c3a43c9960091901d11071c1f2f06762d9 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Wed, 6 Aug 2025 15:59:27 -0400
Subject: [PATCH 02/19] complete multistage startup

---
 .../pricetaker/price_taker_model.py           |  1 +
 .../pricetaker/unit_commitment.py             | 25 ++++++++++---------
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index fb08f84f41..b73f54d9d8 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -684,6 +684,7 @@ def add_startup_shutdown(
                 minimum_up_time=minimum_up_time,
                 minimum_down_time=minimum_down_time,
                 set_time=self.set_time,
+                startup_transition_time={"type1": 6, "type2": 10},
             )
 
         # Save the uptime and downtime data for reference
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index bc03ef2ab2..1c1fc53218 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -19,7 +19,7 @@
 
 from typing import Union, Optional
 from pyomo.common.config import ConfigDict, ConfigValue
-from pyomo.environ import Block, Constraint, Var, RangeSet
+from pyomo.environ import Block, Constraint, Var, Param, RangeSet, Binary
 from idaes.core.util.config import ConfigurationError, is_in_range
 
 
@@ -154,15 +154,15 @@ def startup_shutdown_constraints(
     # Default one startup type. If provided
     if startup_transition_time is not None:
         # at least two types of startup, assume the default one should be at least min_down_time
-        startup_types = {"default": minimum_down_time}
+        startup_type_dict = {"default": minimum_down_time}
         for key in startup_transition_time.keys():
-            startup_types[key] = startup_transition_time[key]
-    
-        startup_names = list(startup_types.keys())
+            startup_type_dict[key] = startup_transition_time[key]
+
+        startup_names = list(startup_type_dict.keys())
 
         # define the startup type as a binary variable
-        blk.startup_type = pyo.Var(set_time, startup_names, within=pyo.Binary)
-        blk.startup_duration = pyo.Param(startup_names, initialize=startup_types)
+        blk.startup_type = Var(set_time, startup_names, within=Binary)
+        blk.startup_duration = Param(startup_names, initialize=startup_type_dict)
 
     @blk.Constraint(set_time)
     def binary_relationship_con(_, t):
@@ -208,12 +208,12 @@ def startup_type_rule(_, t):
 
     if startup_transition_time is not None:
         # add the startup type constraints for each type of startup
-        for key in startup_types.keys():
+        for key in startup_type_dict.keys():
             if key == "default":
-                prev_key = "default"
+                prev_key = key
                 continue
             
-            def startup_type_rule(_, t, key=key):
+            def startup_type_rule(_, t, key=key, prev_key=prev_key):
                 '''
                 Eq 54 in Ben's paper
                 '''
@@ -228,9 +228,10 @@ def startup_type_rule(_, t, key=key):
                 )
             
             setattr(blk, 
-                    f"startup_type_{key}", 
-                    Constraint(rule=startup_type_rule)
+                    f"Startup_Type_Constraint_{key}", 
+                    Constraint(set_time, rule=startup_type_rule)
             )
+            prev_key = key
 
 
 def capacity_limits(

From 03da2abb85aa55e4082f98ff0ab0239fa7b29c30 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Wed, 6 Aug 2025 16:33:24 -0400
Subject: [PATCH 03/19] update startup_type variables to the op_blocks

---
 .../grid_integration/pricetaker/price_taker_model.py   |  4 +++-
 .../grid_integration/pricetaker/unit_commitment.py     | 10 ++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index b73f54d9d8..73032a1ad5 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -676,6 +676,8 @@ def add_startup_shutdown(
         start_shut_blk = getattr(self, start_shut_blk_name)
 
         # pylint: disable=not-an-iterable
+        startup_transition_time = None
+        startup_transition_time = {"type1": 6, "type2": 10}
         for d in self.set_days:
             startup_shutdown_constraints(
                 blk=start_shut_blk[d],
@@ -684,7 +686,7 @@ def add_startup_shutdown(
                 minimum_up_time=minimum_up_time,
                 minimum_down_time=minimum_down_time,
                 set_time=self.set_time,
-                startup_transition_time={"type1": 6, "type2": 10},
+                startup_transition_time=startup_transition_time,
             )
 
         # Save the uptime and downtime data for reference
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 1c1fc53218..f7b26729c0 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -159,9 +159,11 @@ def startup_shutdown_constraints(
             startup_type_dict[key] = startup_transition_time[key]
 
         startup_names = list(startup_type_dict.keys())
+        
+        # define the startup type as a binary variable (in the op_block)
+        for t in set_time:
+            setattr(op_blocks[t], "startup_type", Var(startup_names, within=Binary))
 
-        # define the startup type as a binary variable
-        blk.startup_type = Var(set_time, startup_names, within=Binary)
         blk.startup_duration = Param(startup_names, initialize=startup_type_dict)
 
     @blk.Constraint(set_time)
@@ -203,7 +205,7 @@ def startup_type_rule(_, t):
             return Constraint.Skip
         
         return (
-            sum(blk.startup_type[t, k] for k in startup_names) == op_blocks[t].startup
+            sum(op_blocks[t].startup_type[k] for k in startup_names) == op_blocks[t].startup
         )
 
     if startup_transition_time is not None:
@@ -220,7 +222,7 @@ def startup_type_rule(_, t, key=key, prev_key=prev_key):
                 if t < blk.startup_duration[key]:
                     return Constraint.Skip
                 return (
-                    blk.startup_type[t, key] <= sum(
+                    op_blocks[t].startup_type[key] <= sum(
                         op_blocks[t - i].shutdown for i in range(
                             blk.startup_duration[prev_key], blk.startup_duration[key]
                         )

From 4b88d2db1db376537348dd01d373f7c5a2a1dd88 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Fri, 8 Aug 2025 17:05:05 -0400
Subject: [PATCH 04/19] update

---
 .../grid_integration/pricetaker/price_taker_model.py     | 8 +++++++-
 .../apps/grid_integration/pricetaker/unit_commitment.py  | 9 +++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index 73032a1ad5..0337ca324f 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -622,6 +622,7 @@ def add_startup_shutdown(
         des_block_name: Optional[str] = None,
         minimum_up_time: int = 1,
         minimum_down_time: int = 1,
+        startup_transition_time: Optional[dict] = None,
     ):
         """
         Adds minimum uptime/downtime constraints for a given unit/process
@@ -675,9 +676,14 @@ def add_startup_shutdown(
         setattr(self, start_shut_blk_name, Block(self.set_days))
         start_shut_blk = getattr(self, start_shut_blk_name)
 
-        # pylint: disable=not-an-iterable
+        # 
         startup_transition_time = None
         startup_transition_time = {"type1": 6, "type2": 10}
+
+        if startup_transition_time is not None:
+            self._multiple_startup_types = True
+
+        # pylint: disable=not-an-iterable
         for d in self.set_days:
             startup_shutdown_constraints(
                 blk=start_shut_blk[d],
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index f7b26729c0..075fb0165c 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -235,6 +235,15 @@ def startup_type_rule(_, t, key=key, prev_key=prev_key):
             )
             prev_key = key
 
+        # @op_blocks.Expression(set_time)
+        # def multiple_startup_type_cost(_, t):
+        #     """
+        #     Calculate the startup cost based on the startup type.
+        #     """
+        #     return sum(
+        #         op_blocks[t].startup_type[k] * blk.startup_costs[k]
+        #         for k in startup_names
+        #     )
 
 def capacity_limits(
     blk: Block,

From 09107e373827eb3e7ad860c47f7b401c0165f3a5 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Thu, 14 Aug 2025 12:43:24 -0400
Subject: [PATCH 05/19] fix variable name bug

---
 idaes/apps/grid_integration/pricetaker/unit_commitment.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 075fb0165c..dd4a54d4de 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -197,7 +197,7 @@ def minimum_down_time_con(_, t):
         )
 
     @blk.Constraint(set_time)
-    def startup_type_rule(_, t):
+    def tot_startup_type_rule(_, t):
         '''
         Eq 55 in Ben's paper
         '''
@@ -222,7 +222,7 @@ def startup_type_rule(_, t, key=key, prev_key=prev_key):
                 if t < blk.startup_duration[key]:
                     return Constraint.Skip
                 return (
-                    op_blocks[t].startup_type[key] <= sum(
+                    op_blocks[t].startup_type[prev_key] <= sum(
                         op_blocks[t - i].shutdown for i in range(
                             blk.startup_duration[prev_key], blk.startup_duration[key]
                         )

From 94006ff828011799813b6a2d2fa618f24cd52731 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Thu, 14 Aug 2025 15:34:03 -0400
Subject: [PATCH 06/19] update the transition time format

---
 .../pricetaker/design_and_operation_models.py | 15 +++
 .../pricetaker/price_taker_model.py           | 13 ++-
 .../pricetaker/unit_commitment.py             | 97 +++++++++----------
 3 files changed, 69 insertions(+), 56 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index 1d015f379b..9d4d8d33c1 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -185,6 +185,14 @@ def my_operation_model(m, design_blk):
         ),
     )
 
+    CONFIG.declare(
+        "startup_types",
+        ConfigValue(
+            domain=dict,
+            doc="Dictionary of startup types for the unit/process",
+        )
+    )
+
     # noinspection PyAttributeOutsideInit
     def build(self):
         super().build()
@@ -206,6 +214,13 @@ def build(self):
                 doc="Binary: 1 if the shutdown is initiated, 0 otherwise",
             )
 
+        if self.config.startup_types is not None:
+            self.startup_type_vars = Var(
+                list(self.config.startup_types.keys()),
+                within=Binary,
+                doc="Binary: 1 if the startup type is active, 0 otherwise",
+            )
+
         if self.config.declare_lmp_param:
             self.LMP = Param(
                 initialize=1,
diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index 0337ca324f..0014dfe249 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -150,6 +150,13 @@
     ),
 )
 
+CONFIG.declare(
+    "startup_types",
+    ConfigValue(
+        domain=dict,
+        doc="Dictionary of startup types and their transition times for the unit/process",
+    )
+)
 
 # pylint: disable = too-many-ancestors, too-many-instance-attributes
 class PriceTakerModel(ConcreteModel):
@@ -649,6 +656,8 @@ def add_startup_shutdown(
         # Check minimum_up_time and minimum_down_time for validity
         self.config.minimum_up_time = minimum_up_time
         self.config.minimum_down_time = minimum_down_time
+        # Set startup transition times
+        self.config.startup_types = startup_transition_time
 
         op_blocks = self._get_operation_blocks(
             blk_name=op_block_name,
@@ -676,10 +685,6 @@ def add_startup_shutdown(
         setattr(self, start_shut_blk_name, Block(self.set_days))
         start_shut_blk = getattr(self, start_shut_blk_name)
 
-        # 
-        startup_transition_time = None
-        startup_transition_time = {"type1": 6, "type2": 10}
-
         if startup_transition_time is not None:
             self._multiple_startup_types = True
 
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index dd4a54d4de..8c717785fc 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -151,21 +151,6 @@ def startup_shutdown_constraints(
     Args:
         startup_transition_time (dict): A dictionary with keys as startup types and values are the time of startup transition.
     """
-    # Default one startup type. If provided
-    if startup_transition_time is not None:
-        # at least two types of startup, assume the default one should be at least min_down_time
-        startup_type_dict = {"default": minimum_down_time}
-        for key in startup_transition_time.keys():
-            startup_type_dict[key] = startup_transition_time[key]
-
-        startup_names = list(startup_type_dict.keys())
-        
-        # define the startup type as a binary variable (in the op_block)
-        for t in set_time:
-            setattr(op_blocks[t], "startup_type", Var(startup_names, within=Binary))
-
-        blk.startup_duration = Param(startup_names, initialize=startup_type_dict)
-
     @blk.Constraint(set_time)
     def binary_relationship_con(_, t):
         if t == 1:
@@ -195,55 +180,63 @@ def minimum_down_time_con(_, t):
             sum(op_blocks[i].shutdown for i in range(t - minimum_down_time + 1, t + 1))
             <= install_unit - op_blocks[t].op_mode
         )
+    
+    if startup_transition_time is None:
+        # if there is only one startup type, return
+        return
+
+    # multiple startup types
+    if startup_transition_time is not None:
+        # at least two types of startup
+        startup_names = list(startup_transition_time.keys())
+        # assume the first should be max(min_down_time, startup_transition_time["default"])
+        startup_transition_time[startup_names[0]] = max(minimum_down_time, startup_transition_time[startup_names[0]])
+        # add a check to ensure the startup time is monotonically increasing
+        for i in range(1, len(startup_names)):
+            startup_transition_time[startup_names[i]] = max(
+                startup_transition_time[startup_names[i]],
+                startup_transition_time[startup_names[i - 1]]
+            )
+
+        blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
 
     @blk.Constraint(set_time)
     def tot_startup_type_rule(_, t):
         '''
         Eq 55 in Ben's paper
         '''
-        if startup_transition_time is None:
-            return Constraint.Skip
-        
+    
         return (
-            sum(op_blocks[t].startup_type[k] for k in startup_names) == op_blocks[t].startup
+            sum(op_blocks[t].startup_type_vars[k] for k in startup_names) == op_blocks[t].startup
         )
 
-    if startup_transition_time is not None:
-        # add the startup type constraints for each type of startup
-        for key in startup_type_dict.keys():
-            if key == "default":
-                prev_key = key
-                continue
-            
-            def startup_type_rule(_, t, key=key, prev_key=prev_key):
-                '''
-                Eq 54 in Ben's paper
-                '''
-                if t < blk.startup_duration[key]:
-                    return Constraint.Skip
-                return (
-                    op_blocks[t].startup_type[prev_key] <= sum(
-                        op_blocks[t - i].shutdown for i in range(
-                            blk.startup_duration[prev_key], blk.startup_duration[key]
-                        )
+    
+    # add the startup type constraints for each type of startup
+    for idx, key in enumerate(startup_names):
+        if idx == 0:
+            prev_key = key
+            continue
+        
+        def startup_type_rule(_, t, key=key, prev_key=prev_key):
+            '''
+            Eq 54 in Ben's paper
+            '''
+            if t < blk.startup_duration[key]:
+                return Constraint.Skip
+            return (
+                op_blocks[t].startup_type_vars[prev_key] <= sum(
+                    op_blocks[t - i].shutdown for i in range(
+                        blk.startup_duration[prev_key], blk.startup_duration[key]
                     )
                 )
-            
-            setattr(blk, 
-                    f"Startup_Type_Constraint_{key}", 
-                    Constraint(set_time, rule=startup_type_rule)
             )
-            prev_key = key
-
-        # @op_blocks.Expression(set_time)
-        # def multiple_startup_type_cost(_, t):
-        #     """
-        #     Calculate the startup cost based on the startup type.
-        #     """
-        #     return sum(
-        #         op_blocks[t].startup_type[k] * blk.startup_costs[k]
-        #         for k in startup_names
-        #     )
+            
+        setattr(blk, 
+                f"Startup_Type_Constraint_{key}", 
+                Constraint(set_time, rule=startup_type_rule)
+        )
+        prev_key = key
+        
 
 def capacity_limits(
     blk: Block,

From 67f307f261d9cd6ad0a1f406091597c463a431b4 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Thu, 14 Aug 2025 15:45:06 -0400
Subject: [PATCH 07/19] update docstrings

---
 .../pricetaker/design_and_operation_models.py     |  2 +-
 .../pricetaker/unit_commitment.py                 | 15 +++++++++------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index 9d4d8d33c1..50424d65f4 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -189,7 +189,7 @@ def my_operation_model(m, design_blk):
         "startup_types",
         ConfigValue(
             domain=dict,
-            doc="Dictionary of startup types for the unit/process",
+            doc="Dictionary of startup types and transition times for the unit/process",
         )
     )
 
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 8c717785fc..ca850e0a86 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -144,12 +144,12 @@ def startup_shutdown_constraints(
     startup_transition_time: Optional[dict],
 ):
     """
-    Appends startup and shutdown constraints for a given unit/process
-
+    Appends startup and shutdown constraints for a given unit/process.
     Supports multiples types of startup.
 
     Args:
         startup_transition_time (dict): A dictionary with keys as startup types and values are the time of startup transition.
+
     """
     @blk.Constraint(set_time)
     def binary_relationship_con(_, t):
@@ -187,17 +187,20 @@ def minimum_down_time_con(_, t):
 
     # multiple startup types
     if startup_transition_time is not None:
-        # at least two types of startup
+        # there will be at least two types of startup
         startup_names = list(startup_transition_time.keys())
-        # assume the first should be max(min_down_time, startup_transition_time["default"])
+        
+        # assume the first should be max(min_down_time, startup_transition_time["hot"])
         startup_transition_time[startup_names[0]] = max(minimum_down_time, startup_transition_time[startup_names[0]])
-        # add a check to ensure the startup time is monotonically increasing
+        
+        # add a check to ensure the startup time is monotonically increasing.
         for i in range(1, len(startup_names)):
             startup_transition_time[startup_names[i]] = max(
                 startup_transition_time[startup_names[i]],
                 startup_transition_time[startup_names[i - 1]]
             )
 
+        # this is necessary, because we have updated the startup_transition_time.
         blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
 
     @blk.Constraint(set_time)
@@ -236,7 +239,7 @@ def startup_type_rule(_, t, key=key, prev_key=prev_key):
                 Constraint(set_time, rule=startup_type_rule)
         )
         prev_key = key
-        
+
 
 def capacity_limits(
     blk: Block,

From 94f77290f5a3b936334c052c549a5540339ff604 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Mon, 1 Dec 2025 17:51:26 -0500
Subject: [PATCH 08/19] update various startup codes and add tests

---
 .../pricetaker/design_and_operation_models.py             | 3 ++-
 .../apps/grid_integration/pricetaker/price_taker_model.py | 2 +-
 .../pricetaker/tests/test_design_and_operation_models.py  | 8 ++++++++
 idaes/apps/grid_integration/pricetaker/unit_commitment.py | 5 +++--
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index bd4edb64b5..ae84aa685c 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -424,7 +424,8 @@ def build(self):
                 doc="Binary: 1 if the shutdown is initiated, 0 otherwise",
             )
 
-        if self.config.startup_types is not None:
+        if not self.config.startup_types:
+            # self.config.startup_types can be None or an empty dict
             self.startup_type_vars = Var(
                 list(self.config.startup_types.keys()),
                 within=Binary,
diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index bb83863431..274a856490 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -881,7 +881,7 @@ def add_startup_shutdown(
         setattr(self, start_shut_blk_name, Block(self.set_days))
         start_shut_blk = getattr(self, start_shut_blk_name)
 
-        if startup_transition_time is not None:
+        if not startup_transition_time:
             self._multiple_startup_types = True
 
         # pylint: disable=not-an-iterable
diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
index d6487b6518..2e8f6772b9 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
@@ -270,6 +270,14 @@ def op_model(m, des_blk):
     for attr in ["op_mode", "startup", "shutdown", "power", "LMP"]:
         assert not hasattr(blk.unit_2_op, attr)
 
+    # test the multiple startup types
+    blk.unit_3_op = OperationModel(
+        model_func=op_model,
+        model_args={"des_blk": blk.unit_1_design},
+        startup_types={'hot': 4, 'warm': 8, 'cold': 12}
+    )
+    assert hasattr(blk.unit_3_op, "startup_type_vars")
+
 
 @pytest.mark.unit
 def test_operation_model_class_logger_message1(caplog):
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index ca850e0a86..190646d32e 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -181,12 +181,13 @@ def minimum_down_time_con(_, t):
             <= install_unit - op_blocks[t].op_mode
         )
     
-    if startup_transition_time is None:
+    if not startup_transition_time:
         # if there is only one startup type, return
+        # startup_transition_time can be None or empty dict
         return
 
     # multiple startup types
-    if startup_transition_time is not None:
+    if startup_transition_time:
         # there will be at least two types of startup
         startup_names = list(startup_transition_time.keys())
         

From 4448f130ee3bda98368c898020f00f8c570cb4f9 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Tue, 2 Dec 2025 14:37:03 -0500
Subject: [PATCH 09/19] fix bugs and add more tests

---
 .../pricetaker/design_and_operation_models.py |   2 +-
 .../tests/test_design_and_operation_models.py |   8 +
 .../pricetaker/tests/test_unit_commitment.py  | 255 ++++++++++++++++++
 .../pricetaker/unit_commitment.py             |   2 +-
 4 files changed, 265 insertions(+), 2 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index ae84aa685c..f16370be6d 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -424,7 +424,7 @@ def build(self):
                 doc="Binary: 1 if the shutdown is initiated, 0 otherwise",
             )
 
-        if not self.config.startup_types:
+        if self.config.startup_types:
             # self.config.startup_types can be None or an empty dict
             self.startup_type_vars = Var(
                 list(self.config.startup_types.keys()),
diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
index 2e8f6772b9..7ca9519517 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
@@ -278,6 +278,14 @@ def op_model(m, des_blk):
     )
     assert hasattr(blk.unit_3_op, "startup_type_vars")
 
+    # test the multiple startup types
+    blk.unit_3_op = OperationModel(
+        model_func=op_model,
+        model_args={"des_blk": blk.unit_1_design},
+        startup_types={}
+    )
+    assert not hasattr(blk.unit_3_op, "startup_type_vars")
+
 
 @pytest.mark.unit
 def test_operation_model_class_logger_message1(caplog):
diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py b/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py
index eccabe6d01..6c58992332 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py
@@ -306,3 +306,258 @@ def op_blk(b, _):
     )
     assert con2_2 == str(rl.ramp_down_con[2].expr)
     assert con2_10 == str(rl.ramp_down_con[10].expr)
+
+
+@pytest.mark.unit
+def test_startup_shutdown_constraints_with_multiple_startup_types():
+    """
+    Tests the startup_shutdown_constraints function with multiple startup types
+    covering lines 184-242 which handle startup transition times and constraints
+    """
+    m = pyo.ConcreteModel()
+    m.set_time = pyo.RangeSet(10)
+    startup_transition_time = {"hot": 2, "warm": 5, "cold": 8}
+
+    @m.Block(m.set_time)
+    def op_blk(b, _):
+        b.op_mode = pyo.Var(within=pyo.Binary)
+        b.startup = pyo.Var(within=pyo.Binary)
+        b.shutdown = pyo.Var(within=pyo.Binary)
+        # Add startup_type_vars for multiple startup types
+        b.startup_type_vars = pyo.Var(list(startup_transition_time.keys()), within=pyo.Binary)
+
+    m.startup_shutdown = pyo.Block()
+
+    # Test with multiple startup types
+    uc.startup_shutdown_constraints(
+        blk=m.startup_shutdown,
+        op_blocks=m.op_blk,
+        install_unit=1,
+        minimum_up_time=3,
+        minimum_down_time=4,
+        set_time=m.set_time,
+        startup_transition_time=startup_transition_time,
+    )
+
+    ss = m.startup_shutdown
+
+    # Test that startup_duration parameter is created with correct values
+    # Line 204: blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
+    assert hasattr(ss, 'startup_duration')
+    assert pyo.value(ss.startup_duration["hot"]) == 4  # max(minimum_down_time=4, original=2)
+    assert pyo.value(ss.startup_duration["warm"]) == 5  # max(5, 4)
+    assert pyo.value(ss.startup_duration["cold"]) == 8  # max(8, 5)
+    
+    # Test monotonic increasing property (lines 196-201)
+    startup_names = list(startup_transition_time.keys())
+    for i in range(1, len(startup_names)):
+        current_duration = pyo.value(ss.startup_duration[startup_names[i]])
+        prev_duration = pyo.value(ss.startup_duration[startup_names[i-1]])
+        assert current_duration >= prev_duration
+
+    # Test total startup type constraint exists (lines 206-212)
+    # Eq 55 in Ben's paper
+    assert hasattr(ss, 'tot_startup_type_rule')
+    assert len(ss.tot_startup_type_rule) == 10
+
+    # Check the constraint expression for tot_startup_type_rule
+    expected_expr = (
+        "op_blk[1].startup_type_vars[hot] + "
+        "op_blk[1].startup_type_vars[warm] + "
+        "op_blk[1].startup_type_vars[cold]  ==  op_blk[1].startup"
+    )
+    # print(str(ss.tot_startup_type_rule[1].expr))
+    assert str(ss.tot_startup_type_rule[1].expr) == expected_expr
+
+    # Test individual startup type constraints exist (lines 215-242)
+    # Eq 54 in Ben's paper - should have constraints for warm and cold (not hot since idx=0)
+    assert hasattr(ss, 'Startup_Type_Constraint_warm')
+    assert hasattr(ss, 'Startup_Type_Constraint_cold')
+    
+    # Check that constraints are created for correct indices
+    # For warm startup (duration=5): constraints should exist for t >= 5
+    warm_constraint = getattr(ss, 'Startup_Type_Constraint_warm')
+    assert 1 not in warm_constraint
+    assert 2 not in warm_constraint
+    assert 3 not in warm_constraint
+    assert 4 not in warm_constraint
+    assert 5 in warm_constraint
+    assert 10 in warm_constraint
+    
+    # For cold startup (duration=8): constraints should exist for t >= 8
+    cold_constraint = getattr(ss, 'Startup_Type_Constraint_cold')
+    assert 1 not in cold_constraint
+    assert 7 not in cold_constraint
+    assert 8 in cold_constraint
+    assert 10 in cold_constraint
+
+
+@pytest.mark.unit 
+def test_startup_shutdown_constraints_no_startup_transition_time():
+    """
+    Tests early return when startup_transition_time is None or empty
+    covering lines 184-188
+    """
+    m = pyo.ConcreteModel()
+    m.set_time = pyo.RangeSet(5)
+
+    @m.Block(m.set_time)
+    def op_blk(b, _):
+        b.op_mode = pyo.Var(within=pyo.Binary)
+        b.startup = pyo.Var(within=pyo.Binary)
+        b.shutdown = pyo.Var(within=pyo.Binary)
+
+    m.startup_shutdown = pyo.Block()
+
+    # Test with None startup_transition_time
+    uc.startup_shutdown_constraints(
+        blk=m.startup_shutdown,
+        op_blocks=m.op_blk,
+        install_unit=1,
+        minimum_up_time=2,
+        minimum_down_time=2,
+        set_time=m.set_time,
+        startup_transition_time=None,
+    )
+
+    ss = m.startup_shutdown
+    
+    # Should have basic constraints but no startup type specific constraints
+    assert hasattr(ss, 'binary_relationship_con')
+    assert hasattr(ss, 'minimum_up_time_con')
+    assert hasattr(ss, 'minimum_down_time_con')
+    
+    # Should NOT have startup type specific attributes
+    assert not hasattr(ss, 'startup_duration')
+    assert not hasattr(ss, 'tot_startup_type_rule')
+    assert not hasattr(ss, 'Startup_Type_Constraint_warm')
+
+    # Test with empty dict startup_transition_time
+    m2 = pyo.ConcreteModel()
+    m2.set_time = pyo.RangeSet(5)
+
+    @m2.Block(m2.set_time)
+    def op_blk2(b, _):
+        b.op_mode = pyo.Var(within=pyo.Binary)
+        b.startup = pyo.Var(within=pyo.Binary)
+        b.shutdown = pyo.Var(within=pyo.Binary)
+
+    m2.startup_shutdown = pyo.Block()
+
+    uc.startup_shutdown_constraints(
+        blk=m2.startup_shutdown,
+        op_blocks=m2.op_blk2,
+        install_unit=1,
+        minimum_up_time=2,
+        minimum_down_time=2,
+        set_time=m2.set_time,
+        startup_transition_time={},
+    )
+
+    ss2 = m2.startup_shutdown
+    
+    # Should have basic constraints but no startup type specific constraints
+    assert hasattr(ss2, 'binary_relationship_con')
+    assert not hasattr(ss2, 'startup_duration')
+    assert not hasattr(ss2, 'tot_startup_type_rule')
+
+
+@pytest.mark.unit
+def test_startup_shutdown_constraints_single_startup_type():
+    """
+    Tests the case with single startup type in startup_transition_time dict
+    This should still create startup duration parameter and constraints
+    """
+    m = pyo.ConcreteModel()
+    m.set_time = pyo.RangeSet(8)
+
+    @m.Block(m.set_time)
+    def op_blk(b, _):
+        b.op_mode = pyo.Var(within=pyo.Binary)
+        b.startup = pyo.Var(within=pyo.Binary)
+        b.shutdown = pyo.Var(within=pyo.Binary)
+        # Add startup_type_vars for single startup type
+        b.startup_type_vars = {}
+        b.startup_type_vars["hot"] = pyo.Var(within=pyo.Binary)
+
+    m.startup_shutdown = pyo.Block()
+
+    # Test with single startup type - should respect minimum_down_time
+    startup_transition_time = {"hot": 2}  # Less than minimum_down_time=3
+    
+    uc.startup_shutdown_constraints(
+        blk=m.startup_shutdown,
+        op_blocks=m.op_blk,
+        install_unit=1,
+        minimum_up_time=2,
+        minimum_down_time=3,
+        set_time=m.set_time,
+        startup_transition_time=startup_transition_time,
+    )
+
+    ss = m.startup_shutdown
+
+    # Should create startup_duration parameter
+    assert hasattr(ss, 'startup_duration')
+    # Hot startup should be adjusted to minimum_down_time (line 195)
+    assert pyo.value(ss.startup_duration["hot"]) == 3  # max(minimum_down_time=3, original=2)
+    
+    # Should create tot_startup_type_rule constraint
+    assert hasattr(ss, 'tot_startup_type_rule')
+    assert len(ss.tot_startup_type_rule) == 8
+    
+    # Should NOT create individual startup type constraints since there's only one type (idx=0 case)
+    assert not hasattr(ss, 'Startup_Type_Constraint_hot')
+
+
+@pytest.mark.unit
+def test_startup_shutdown_constraints_constraint_expressions():
+    """
+    Tests the specific constraint expressions created for multiple startup types
+    Verifies the mathematical formulation from lines 225-241
+    """
+    m = pyo.ConcreteModel()
+    m.set_time = pyo.RangeSet(10)
+
+    @m.Block(m.set_time)
+    def op_blk(b, _):
+        b.op_mode = pyo.Var(within=pyo.Binary)
+        b.startup = pyo.Var(within=pyo.Binary)
+        b.shutdown = pyo.Var(within=pyo.Binary)
+        b.startup_type_vars = {}
+        b.startup_type_vars["hot"] = pyo.Var(within=pyo.Binary)
+        b.startup_type_vars["warm"] = pyo.Var(within=pyo.Binary)
+
+    m.startup_shutdown = pyo.Block()
+
+    startup_transition_time = {"hot": 3, "warm": 6}
+    
+    uc.startup_shutdown_constraints(
+        blk=m.startup_shutdown,
+        op_blocks=m.op_blk,
+        install_unit=1,
+        minimum_up_time=2,
+        minimum_down_time=4,
+        set_time=m.set_time,
+        startup_transition_time=startup_transition_time,
+    )
+
+    ss = m.startup_shutdown
+
+    # Test tot_startup_type_rule constraint expression (Eq 55)
+    # Verify the constraint structure (exact string may vary due to variable representation)
+    tot_expr_str = str(ss.tot_startup_type_rule[5].expr)
+    assert "==" in tot_expr_str
+    assert "op_blk[5].startup" in tot_expr_str
+
+    # Test individual startup type constraint (Eq 54)
+    # For warm startup (duration=6): constraint should exist for t=6 and above
+    warm_constraint = getattr(ss, 'Startup_Type_Constraint_warm')
+    assert 6 in warm_constraint
+    
+    # The constraint should be: hot_startup <= sum of shutdowns in range [hot_duration, warm_duration)
+    # Range should be [4, 6) = [4, 5] but Pyomo uses t-i indexing, so it's [2, 1]
+    warm_expr_str = str(warm_constraint[6].expr)
+    assert "<=" in warm_expr_str
+    assert "op_blk[2].shutdown" in warm_expr_str
+    assert "op_blk[1].shutdown" in warm_expr_str
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 190646d32e..e75dce50c2 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -141,7 +141,7 @@ def startup_shutdown_constraints(
     minimum_up_time: int,
     minimum_down_time: int,
     set_time: RangeSet,
-    startup_transition_time: Optional[dict],
+    startup_transition_time: Optional[dict] = None,
 ):
     """
     Appends startup and shutdown constraints for a given unit/process.

From 43e5c1b0bf8caf063444ca33a3ebd3084af08f07 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Tue, 2 Dec 2025 14:52:22 -0500
Subject: [PATCH 10/19] use black to reformulate

---
 .../pricetaker/design_and_operation_models.py |  2 +-
 .../pricetaker/price_taker_model.py           |  3 +-
 .../tests/test_design_and_operation_models.py |  6 +-
 .../pricetaker/tests/test_unit_commitment.py  | 76 ++++++++++---------
 4 files changed, 46 insertions(+), 41 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index f16370be6d..bec24dbc2d 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -400,7 +400,7 @@ def my_operation_model(m, design_blk):
         ConfigValue(
             domain=dict,
             doc="Dictionary of startup types and transition times for the unit/process",
-        )
+        ),
     )
 
     # noinspection PyAttributeOutsideInit
diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index 274a856490..da64ab062b 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -161,9 +161,10 @@
     ConfigValue(
         domain=dict,
         doc="Dictionary of startup types and their transition times for the unit/process",
-    )
+    ),
 )
 
+
 # pylint: disable = too-many-ancestors, too-many-instance-attributes
 class PriceTakerModel(ConcreteModel):
     """Builds a price-taker model for a given system"""
diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
index 7ca9519517..f33f4c26a6 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
@@ -274,15 +274,13 @@ def op_model(m, des_blk):
     blk.unit_3_op = OperationModel(
         model_func=op_model,
         model_args={"des_blk": blk.unit_1_design},
-        startup_types={'hot': 4, 'warm': 8, 'cold': 12}
+        startup_types={"hot": 4, "warm": 8, "cold": 12},
     )
     assert hasattr(blk.unit_3_op, "startup_type_vars")
 
     # test the multiple startup types
     blk.unit_3_op = OperationModel(
-        model_func=op_model,
-        model_args={"des_blk": blk.unit_1_design},
-        startup_types={}
+        model_func=op_model, model_args={"des_blk": blk.unit_1_design}, startup_types={}
     )
     assert not hasattr(blk.unit_3_op, "startup_type_vars")
 
diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py b/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py
index 6c58992332..081a87a9d3 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_unit_commitment.py
@@ -324,7 +324,9 @@ def op_blk(b, _):
         b.startup = pyo.Var(within=pyo.Binary)
         b.shutdown = pyo.Var(within=pyo.Binary)
         # Add startup_type_vars for multiple startup types
-        b.startup_type_vars = pyo.Var(list(startup_transition_time.keys()), within=pyo.Binary)
+        b.startup_type_vars = pyo.Var(
+            list(startup_transition_time.keys()), within=pyo.Binary
+        )
 
     m.startup_shutdown = pyo.Block()
 
@@ -343,21 +345,23 @@ def op_blk(b, _):
 
     # Test that startup_duration parameter is created with correct values
     # Line 204: blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
-    assert hasattr(ss, 'startup_duration')
-    assert pyo.value(ss.startup_duration["hot"]) == 4  # max(minimum_down_time=4, original=2)
+    assert hasattr(ss, "startup_duration")
+    assert (
+        pyo.value(ss.startup_duration["hot"]) == 4
+    )  # max(minimum_down_time=4, original=2)
     assert pyo.value(ss.startup_duration["warm"]) == 5  # max(5, 4)
     assert pyo.value(ss.startup_duration["cold"]) == 8  # max(8, 5)
-    
+
     # Test monotonic increasing property (lines 196-201)
     startup_names = list(startup_transition_time.keys())
     for i in range(1, len(startup_names)):
         current_duration = pyo.value(ss.startup_duration[startup_names[i]])
-        prev_duration = pyo.value(ss.startup_duration[startup_names[i-1]])
+        prev_duration = pyo.value(ss.startup_duration[startup_names[i - 1]])
         assert current_duration >= prev_duration
 
     # Test total startup type constraint exists (lines 206-212)
     # Eq 55 in Ben's paper
-    assert hasattr(ss, 'tot_startup_type_rule')
+    assert hasattr(ss, "tot_startup_type_rule")
     assert len(ss.tot_startup_type_rule) == 10
 
     # Check the constraint expression for tot_startup_type_rule
@@ -371,28 +375,28 @@ def op_blk(b, _):
 
     # Test individual startup type constraints exist (lines 215-242)
     # Eq 54 in Ben's paper - should have constraints for warm and cold (not hot since idx=0)
-    assert hasattr(ss, 'Startup_Type_Constraint_warm')
-    assert hasattr(ss, 'Startup_Type_Constraint_cold')
-    
+    assert hasattr(ss, "Startup_Type_Constraint_warm")
+    assert hasattr(ss, "Startup_Type_Constraint_cold")
+
     # Check that constraints are created for correct indices
     # For warm startup (duration=5): constraints should exist for t >= 5
-    warm_constraint = getattr(ss, 'Startup_Type_Constraint_warm')
+    warm_constraint = getattr(ss, "Startup_Type_Constraint_warm")
     assert 1 not in warm_constraint
     assert 2 not in warm_constraint
     assert 3 not in warm_constraint
     assert 4 not in warm_constraint
     assert 5 in warm_constraint
     assert 10 in warm_constraint
-    
+
     # For cold startup (duration=8): constraints should exist for t >= 8
-    cold_constraint = getattr(ss, 'Startup_Type_Constraint_cold')
+    cold_constraint = getattr(ss, "Startup_Type_Constraint_cold")
     assert 1 not in cold_constraint
     assert 7 not in cold_constraint
     assert 8 in cold_constraint
     assert 10 in cold_constraint
 
 
-@pytest.mark.unit 
+@pytest.mark.unit
 def test_startup_shutdown_constraints_no_startup_transition_time():
     """
     Tests early return when startup_transition_time is None or empty
@@ -421,16 +425,16 @@ def op_blk(b, _):
     )
 
     ss = m.startup_shutdown
-    
+
     # Should have basic constraints but no startup type specific constraints
-    assert hasattr(ss, 'binary_relationship_con')
-    assert hasattr(ss, 'minimum_up_time_con')
-    assert hasattr(ss, 'minimum_down_time_con')
-    
+    assert hasattr(ss, "binary_relationship_con")
+    assert hasattr(ss, "minimum_up_time_con")
+    assert hasattr(ss, "minimum_down_time_con")
+
     # Should NOT have startup type specific attributes
-    assert not hasattr(ss, 'startup_duration')
-    assert not hasattr(ss, 'tot_startup_type_rule')
-    assert not hasattr(ss, 'Startup_Type_Constraint_warm')
+    assert not hasattr(ss, "startup_duration")
+    assert not hasattr(ss, "tot_startup_type_rule")
+    assert not hasattr(ss, "Startup_Type_Constraint_warm")
 
     # Test with empty dict startup_transition_time
     m2 = pyo.ConcreteModel()
@@ -455,11 +459,11 @@ def op_blk2(b, _):
     )
 
     ss2 = m2.startup_shutdown
-    
+
     # Should have basic constraints but no startup type specific constraints
-    assert hasattr(ss2, 'binary_relationship_con')
-    assert not hasattr(ss2, 'startup_duration')
-    assert not hasattr(ss2, 'tot_startup_type_rule')
+    assert hasattr(ss2, "binary_relationship_con")
+    assert not hasattr(ss2, "startup_duration")
+    assert not hasattr(ss2, "tot_startup_type_rule")
 
 
 @pytest.mark.unit
@@ -484,7 +488,7 @@ def op_blk(b, _):
 
     # Test with single startup type - should respect minimum_down_time
     startup_transition_time = {"hot": 2}  # Less than minimum_down_time=3
-    
+
     uc.startup_shutdown_constraints(
         blk=m.startup_shutdown,
         op_blocks=m.op_blk,
@@ -498,16 +502,18 @@ def op_blk(b, _):
     ss = m.startup_shutdown
 
     # Should create startup_duration parameter
-    assert hasattr(ss, 'startup_duration')
+    assert hasattr(ss, "startup_duration")
     # Hot startup should be adjusted to minimum_down_time (line 195)
-    assert pyo.value(ss.startup_duration["hot"]) == 3  # max(minimum_down_time=3, original=2)
-    
+    assert (
+        pyo.value(ss.startup_duration["hot"]) == 3
+    )  # max(minimum_down_time=3, original=2)
+
     # Should create tot_startup_type_rule constraint
-    assert hasattr(ss, 'tot_startup_type_rule')
+    assert hasattr(ss, "tot_startup_type_rule")
     assert len(ss.tot_startup_type_rule) == 8
-    
+
     # Should NOT create individual startup type constraints since there's only one type (idx=0 case)
-    assert not hasattr(ss, 'Startup_Type_Constraint_hot')
+    assert not hasattr(ss, "Startup_Type_Constraint_hot")
 
 
 @pytest.mark.unit
@@ -531,7 +537,7 @@ def op_blk(b, _):
     m.startup_shutdown = pyo.Block()
 
     startup_transition_time = {"hot": 3, "warm": 6}
-    
+
     uc.startup_shutdown_constraints(
         blk=m.startup_shutdown,
         op_blocks=m.op_blk,
@@ -552,9 +558,9 @@ def op_blk(b, _):
 
     # Test individual startup type constraint (Eq 54)
     # For warm startup (duration=6): constraint should exist for t=6 and above
-    warm_constraint = getattr(ss, 'Startup_Type_Constraint_warm')
+    warm_constraint = getattr(ss, "Startup_Type_Constraint_warm")
     assert 6 in warm_constraint
-    
+
     # The constraint should be: hot_startup <= sum of shutdowns in range [hot_duration, warm_duration)
     # Range should be [4, 6) = [4, 5] but Pyomo uses t-i indexing, so it's [2, 1]
     warm_expr_str = str(warm_constraint[6].expr)

From e65d9805744527b04a8037fc92b8c948722ab912 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Tue, 2 Dec 2025 15:16:39 -0500
Subject: [PATCH 11/19] further reformat using black

---
 .../pricetaker/unit_commitment.py             | 47 ++++++++++---------
 1 file changed, 25 insertions(+), 22 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index e75dce50c2..5a08d70734 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -151,6 +151,7 @@ def startup_shutdown_constraints(
         startup_transition_time (dict): A dictionary with keys as startup types and values are the time of startup transition.
 
     """
+
     @blk.Constraint(set_time)
     def binary_relationship_con(_, t):
         if t == 1:
@@ -180,7 +181,7 @@ def minimum_down_time_con(_, t):
             sum(op_blocks[i].shutdown for i in range(t - minimum_down_time + 1, t + 1))
             <= install_unit - op_blocks[t].op_mode
         )
-    
+
     if not startup_transition_time:
         # if there is only one startup type, return
         # startup_transition_time can be None or empty dict
@@ -190,15 +191,17 @@ def minimum_down_time_con(_, t):
     if startup_transition_time:
         # there will be at least two types of startup
         startup_names = list(startup_transition_time.keys())
-        
+
         # assume the first should be max(min_down_time, startup_transition_time["hot"])
-        startup_transition_time[startup_names[0]] = max(minimum_down_time, startup_transition_time[startup_names[0]])
-        
+        startup_transition_time[startup_names[0]] = max(
+            minimum_down_time, startup_transition_time[startup_names[0]]
+        )
+
         # add a check to ensure the startup time is monotonically increasing.
         for i in range(1, len(startup_names)):
             startup_transition_time[startup_names[i]] = max(
                 startup_transition_time[startup_names[i]],
-                startup_transition_time[startup_names[i - 1]]
+                startup_transition_time[startup_names[i - 1]],
             )
 
         # this is necessary, because we have updated the startup_transition_time.
@@ -206,38 +209,38 @@ def minimum_down_time_con(_, t):
 
     @blk.Constraint(set_time)
     def tot_startup_type_rule(_, t):
-        '''
+        """
         Eq 55 in Ben's paper
-        '''
-    
+        """
+
         return (
-            sum(op_blocks[t].startup_type_vars[k] for k in startup_names) == op_blocks[t].startup
+            sum(op_blocks[t].startup_type_vars[k] for k in startup_names)
+            == op_blocks[t].startup
         )
 
-    
     # add the startup type constraints for each type of startup
     for idx, key in enumerate(startup_names):
         if idx == 0:
             prev_key = key
             continue
-        
+
         def startup_type_rule(_, t, key=key, prev_key=prev_key):
-            '''
+            """
             Eq 54 in Ben's paper
-            '''
+            """
             if t < blk.startup_duration[key]:
                 return Constraint.Skip
-            return (
-                op_blocks[t].startup_type_vars[prev_key] <= sum(
-                    op_blocks[t - i].shutdown for i in range(
-                        blk.startup_duration[prev_key], blk.startup_duration[key]
-                    )
+            return op_blocks[t].startup_type_vars[prev_key] <= sum(
+                op_blocks[t - i].shutdown
+                for i in range(
+                    blk.startup_duration[prev_key], blk.startup_duration[key]
                 )
             )
-            
-        setattr(blk, 
-                f"Startup_Type_Constraint_{key}", 
-                Constraint(set_time, rule=startup_type_rule)
+
+        setattr(
+            blk,
+            f"Startup_Type_Constraint_{key}",
+            Constraint(set_time, rule=startup_type_rule),
         )
         prev_key = key
 

From 5948e7574e36f5139f3019879b00c6b9386dcf17 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Fri, 19 Dec 2025 14:15:13 -0500
Subject: [PATCH 12/19] revome an unsed variable

---
 idaes/apps/grid_integration/pricetaker/price_taker_model.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index 2ff57793d7..9edd3bb081 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -882,9 +882,6 @@ def add_startup_shutdown(
         setattr(self, start_shut_blk_name, Block(self.set_days))
         start_shut_blk = getattr(self, start_shut_blk_name)
 
-        if not startup_transition_time:
-            self._multiple_startup_types = True
-
         # pylint: disable=not-an-iterable
         for d in self.set_days:
             startup_shutdown_constraints(

From 8bac610d0440fb2aba2494cedb98b70ca75909d8 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Mon, 12 Jan 2026 16:14:41 -0500
Subject: [PATCH 13/19] update to address comments from PR

---
 .../pricetaker/design_and_operation_models.py | 40 ++++++++++++++++++-
 .../pricetaker/price_taker_model.py           |  3 +-
 .../pricetaker/unit_commitment.py             | 14 +++++--
 3 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index bc134cb5ba..e06031e1ae 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -85,6 +85,44 @@ def is_valid_polynomial_surrogate_data(data: dict):
     return new_data
 
 
+def is_valid_startup_types(data):
+    """Validate if the startup_types received is valid"""
+
+    if data is None:
+        # if data is None, it is okay and return None
+        return None
+
+    if not isinstance(data, dict):
+        raise TypeError("Data must be a dictionary.")
+
+    if len(data) == 0:
+        # set to None instead of an empty dict.
+        raise ConfigurationError("Received an empty dictionary for startup types")
+
+    # check the key names and make sure space is handled correctly.
+    # use a method to check if a string is a valid variable name. string.isidentifier() works for now.
+
+    for key, value in data.items():
+        if not isinstance(key, str):
+            raise TypeError("key must be a valid string.")
+
+        if not key.isidentifier():
+            raise ConfigurationError(
+                f"Key '{key}' is not a valid Python variable name. "
+                "Keys must be valid identifiers."
+            )
+
+        if not isinstance(value, int):
+            raise TypeError("value must be an int")
+
+    # Values must be unique, as they correspond to different startup types
+    if len(data.values()) > len(set(data.values())):
+        raise ConfigurationError("Startup time for two or more startup types is the same.")
+
+    # Return a dictionary after sorting based on values
+    return dict(sorted(data.items(), key=lambda item: item[1]))
+
+
 # pylint: disable = attribute-defined-outside-init, too-many-ancestors
 # pylint: disable = invalid-name, logging-fstring-interpolation
 @declare_process_block_class("DesignModel")
@@ -398,7 +436,7 @@ def my_operation_model(m, design_blk):
     CONFIG.declare(
         "startup_types",
         ConfigValue(
-            domain=dict,
+            domain=is_valid_startup_types,
             doc="Dictionary of startup types and transition times for the unit/process",
         ),
     )
diff --git a/idaes/apps/grid_integration/pricetaker/price_taker_model.py b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
index 9edd3bb081..6f866194e0 100644
--- a/idaes/apps/grid_integration/pricetaker/price_taker_model.py
+++ b/idaes/apps/grid_integration/pricetaker/price_taker_model.py
@@ -42,6 +42,7 @@
     DesignModelData,
     OperationModelData,
     StorageModelData,
+    is_valid_startup_types,
 )
 from idaes.apps.grid_integration.pricetaker.clustering import (
     generate_daily_data,
@@ -159,7 +160,7 @@
 CONFIG.declare(
     "startup_types",
     ConfigValue(
-        domain=dict,
+        domain=is_valid_startup_types,
         doc="Dictionary of startup types and their transition times for the unit/process",
     ),
 )
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 3bcabff973..5df313c5ac 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -15,6 +15,11 @@
 This module contains functions that build unit commitment-type
 constraints: startup/shutdown, uptime/downtime constraints,
 capacity limit constraints, and ramping constraints.
+
+The unit commitment model is taken from: 
+Knueven, Bernard, James Ostrowski, and Jean-Paul Watson. 
+"On mixed-integer programming formulations for the unit commitment problem." 
+INFORMS Journal on Computing 32, no. 4 (2020): 857-876.
 """
 
 from typing import Union, Optional
@@ -148,7 +153,7 @@ def startup_shutdown_constraints(
     Supports multiples types of startup.
 
     Args:
-        startup_transition_time (dict): A dictionary with keys as startup types and values are the time of startup transition.
+        startup_transition_time (dict or None): A dictionary with keys as startup types and values are the time of startup transition.
 
     """
 
@@ -182,9 +187,10 @@ def minimum_down_time_con(_, t):
             <= install_unit - op_blocks[t].op_mode
         )
 
-    if not startup_transition_time:
+    if startup_transition_time is None or len(startup_transition_time) == 0:
         # if there is only one startup type, return
         # startup_transition_time can be None or empty dict
+        # This is a double insurance check, that empty dict or None is not passed
         return
 
     # multiple startup types
@@ -210,7 +216,7 @@ def minimum_down_time_con(_, t):
     @blk.Constraint(set_time)
     def tot_startup_type_rule(_, t):
         """
-        Eq 55 in Ben's paper
+        Eq 55 in Knueven et.al.
         """
 
         return (
@@ -226,7 +232,7 @@ def tot_startup_type_rule(_, t):
 
         def startup_type_rule(_, t, key=key, prev_key=prev_key):
             """
-            Eq 54 in Ben's paper
+            Eq 54 in Knueven et.al.
             """
             if t < blk.startup_duration[key]:
                 return Constraint.Skip

From c32e950e6b45f4e238e38b3bb464a8c613bc9ab1 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Mon, 12 Jan 2026 16:20:07 -0500
Subject: [PATCH 14/19] use black to format codes

---
 .../pricetaker/design_and_operation_models.py                 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index e06031e1ae..fe0772ba48 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -117,7 +117,9 @@ def is_valid_startup_types(data):
 
     # Values must be unique, as they correspond to different startup types
     if len(data.values()) > len(set(data.values())):
-        raise ConfigurationError("Startup time for two or more startup types is the same.")
+        raise ConfigurationError(
+            "Startup time for two or more startup types is the same."
+        )
 
     # Return a dictionary after sorting based on values
     return dict(sorted(data.items(), key=lambda item: item[1]))

From 3938e1ff3534db19ecc4c3cb0420aa0b910ac938 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Mon, 12 Jan 2026 17:19:55 -0500
Subject: [PATCH 15/19] update and fix errors in the tests

---
 .../tests/test_design_and_operation_models.py    | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
index 867e63c3d1..b48eee8d0d 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
@@ -23,10 +23,20 @@
     _is_valid_data_type_for_storage_model,
     is_valid_variable_design_data,
     is_valid_polynomial_surrogate_data,
+    is_valid_startup_types,
 )
 from idaes.core.util.config import ConfigurationError
 
 
+@pytest.mark.unit
+def test_is_valid_startup_types_empty_dict():
+    """Tests that is_valid_startup_types raises error for empty dictionary"""
+    with pytest.raises(
+        ConfigurationError, match="Received an empty dictionary for startup types"
+    ):
+        is_valid_startup_types({})
+
+
 @pytest.mark.unit
 def test_format_data():
     """Tests the _format_data function"""
@@ -278,9 +288,11 @@ def op_model(m, des_blk):
     )
     assert hasattr(blk.unit_3_op, "startup_type_vars")
 
-    # test the multiple startup types
+    # test the startup types = None
     blk.unit_3_op = OperationModel(
-        model_func=op_model, model_args={"des_blk": blk.unit_1_design}, startup_types={}
+        model_func=op_model,
+        model_args={"des_blk": blk.unit_1_design},
+        startup_types=None,
     )
     assert not hasattr(blk.unit_3_op, "startup_type_vars")
 

From 4ec1457e9acd296f01763ab177bd6e5dc8019b67 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Wed, 14 Jan 2026 19:44:42 -0500
Subject: [PATCH 16/19] update the functions and remove unnecessary lines

---
 .../pricetaker/design_and_operation_models.py         |  4 ----
 .../grid_integration/pricetaker/unit_commitment.py    | 11 ++---------
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index fe0772ba48..af897db137 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -88,10 +88,6 @@ def is_valid_polynomial_surrogate_data(data: dict):
 def is_valid_startup_types(data):
     """Validate if the startup_types received is valid"""
 
-    if data is None:
-        # if data is None, it is okay and return None
-        return None
-
     if not isinstance(data, dict):
         raise TypeError("Data must be a dictionary.")
 
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 5df313c5ac..34b521ecdc 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -189,8 +189,8 @@ def minimum_down_time_con(_, t):
 
     if startup_transition_time is None or len(startup_transition_time) == 0:
         # if there is only one startup type, return
-        # startup_transition_time can be None or empty dict
-        # This is a double insurance check, that empty dict or None is not passed
+        # startup_transition_time can be None.
+        # This is a double insurance check, that empty dict or None will skip the following.
         return
 
     # multiple startup types
@@ -203,13 +203,6 @@ def minimum_down_time_con(_, t):
             minimum_down_time, startup_transition_time[startup_names[0]]
         )
 
-        # add a check to ensure the startup time is monotonically increasing.
-        for i in range(1, len(startup_names)):
-            startup_transition_time[startup_names[i]] = max(
-                startup_transition_time[startup_names[i]],
-                startup_transition_time[startup_names[i - 1]],
-            )
-
         # this is necessary, because we have updated the startup_transition_time.
         blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
 

From 50b68c11213b92d77baeeac2895666c699eba7c4 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Fri, 16 Jan 2026 10:29:47 -0500
Subject: [PATCH 17/19] update tests

---
 .../tests/test_design_and_operation_models.py | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
index b48eee8d0d..2c48d96eaa 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
@@ -37,6 +37,35 @@ def test_is_valid_startup_types_empty_dict():
         is_valid_startup_types({})
 
 
+@pytest.mark.unit
+def test_is_valid_startup_types_invalid_inputs():
+    """Tests that is_valid_startup_types rejects invalid inputs"""
+
+    with pytest.raises(TypeError, match="Data must be a dictionary."):
+        is_valid_startup_types([("hot", 4)])
+
+    with pytest.raises(TypeError, match="Data must be a dictionary."):
+        is_valid_startup_types(3.14)
+
+    with pytest.raises(TypeError, match="key must be a valid string."):
+        is_valid_startup_types({1: 4})
+
+    with pytest.raises(
+        ConfigurationError,
+        match="Key 'hot-start' is not a valid Python variable name. Keys must be valid identifiers.",
+    ):
+        is_valid_startup_types({"hot-start": 4})
+
+    with pytest.raises(TypeError, match="value must be an int"):
+        is_valid_startup_types({"hot": 4.2})
+
+    with pytest.raises(
+        ConfigurationError,
+        match="Startup time for two or more startup types is the same.",
+    ):
+        is_valid_startup_types({"hot": 4, "warm": 4})
+
+
 @pytest.mark.unit
 def test_format_data():
     """Tests the _format_data function"""
@@ -423,6 +452,15 @@ def test_is_valid_data_type_for_storage_model():
     )
 
 
+@pytest.mark.unit
+def test_is_valid_startup_types():
+    """Tests the is_valid_startup_types function"""
+    # Test the correct data structure is returned
+    data = is_valid_startup_types({"warm": 8, "hot": 4, "cold": 12})
+    assert list(data.keys()) == ["hot", "warm", "cold"]
+    assert data == {"hot": 4, "warm": 8, "cold": 12}
+
+
 @pytest.mark.unit
 def test_storage_model_fixed_design():
     """Tests the StorageModel class with int/float-type arguments"""

From ac54a1284dc121750fa6dc3d72362b5ac32ae892 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Wed, 4 Feb 2026 22:17:02 -0500
Subject: [PATCH 18/19] update tests

---
 .../pricetaker/design_and_operation_models.py | 12 +++++++++--
 .../tests/test_design_and_operation_models.py | 14 +++++++++----
 .../pricetaker/unit_commitment.py             | 20 +++++++++----------
 3 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index af897db137..bf4305ffe3 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -94,6 +94,15 @@ def is_valid_startup_types(data):
     if len(data) == 0:
         # set to None instead of an empty dict.
         raise ConfigurationError("Received an empty dictionary for startup types")
+    
+    if len(data) == 1:
+        raise ConfigurationError(
+            "At least two startup types must be defined for the unit/process. \n"
+            "if startup_types = {\"hot\": 4, \"warm\": 8, \"cold\": 12}, \n"
+            "then when downtime is between 4 to 8 -> hot startup; \n"
+            "when downtime is between 8 to 12 -> warm startup; \n"
+            "when downtime is greater than 12 -> cold startup. \n"
+        )
 
     # check the key names and make sure space is handled correctly.
     # use a method to check if a string is a valid variable name. string.isidentifier() works for now.
@@ -460,8 +469,7 @@ def build(self):
                 doc="Binary: 1 if the shutdown is initiated, 0 otherwise",
             )
 
-        if self.config.startup_types:
-            # self.config.startup_types can be None or an empty dict
+        if self.config.startup_types is not None:
             self.startup_type_vars = Var(
                 list(self.config.startup_types.keys()),
                 within=Binary,
diff --git a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
index 2c48d96eaa..349ec556c9 100644
--- a/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/tests/test_design_and_operation_models.py
@@ -42,22 +42,28 @@ def test_is_valid_startup_types_invalid_inputs():
     """Tests that is_valid_startup_types rejects invalid inputs"""
 
     with pytest.raises(TypeError, match="Data must be a dictionary."):
-        is_valid_startup_types([("hot", 4)])
+        is_valid_startup_types([("hot", 4), ("warm", 8)])
 
     with pytest.raises(TypeError, match="Data must be a dictionary."):
         is_valid_startup_types(3.14)
 
+    with pytest.raises(
+        ConfigurationError,
+        match="At least two startup types must be defined for the unit/process.",
+    ):
+        is_valid_startup_types({"hot": 4})
+
     with pytest.raises(TypeError, match="key must be a valid string."):
-        is_valid_startup_types({1: 4})
+        is_valid_startup_types({1: 4, 2: 8})
 
     with pytest.raises(
         ConfigurationError,
         match="Key 'hot-start' is not a valid Python variable name. Keys must be valid identifiers.",
     ):
-        is_valid_startup_types({"hot-start": 4})
+        is_valid_startup_types({"hot-start": 4, "warm-start": 8})
 
     with pytest.raises(TypeError, match="value must be an int"):
-        is_valid_startup_types({"hot": 4.2})
+        is_valid_startup_types({"hot": 4.2, "warm": 8.1})
 
     with pytest.raises(
         ConfigurationError,
diff --git a/idaes/apps/grid_integration/pricetaker/unit_commitment.py b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
index 34b521ecdc..55694e0453 100644
--- a/idaes/apps/grid_integration/pricetaker/unit_commitment.py
+++ b/idaes/apps/grid_integration/pricetaker/unit_commitment.py
@@ -193,18 +193,16 @@ def minimum_down_time_con(_, t):
         # This is a double insurance check, that empty dict or None will skip the following.
         return
 
-    # multiple startup types
-    if startup_transition_time:
-        # there will be at least two types of startup
-        startup_names = list(startup_transition_time.keys())
-
-        # assume the first should be max(min_down_time, startup_transition_time["hot"])
-        startup_transition_time[startup_names[0]] = max(
-            minimum_down_time, startup_transition_time[startup_names[0]]
-        )
+    # there will be at least two types of startup
+    startup_names = list(startup_transition_time.keys())
+
+    # assume the first should be max(min_down_time, startup_transition_time["hot"])
+    startup_transition_time[startup_names[0]] = max(
+        minimum_down_time, startup_transition_time[startup_names[0]]
+    )
 
-        # this is necessary, because we have updated the startup_transition_time.
-        blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
+    # this is necessary, because we have updated the startup_transition_time.
+    blk.startup_duration = Param(startup_names, initialize=startup_transition_time)
 
     @blk.Constraint(set_time)
     def tot_startup_type_rule(_, t):

From cbe6eb9dfc12c8c1ddedcea41418dc0f3e52dad3 Mon Sep 17 00:00:00 2001
From: Xinhe Chen <xchen24@nd.edu>
Date: Wed, 4 Feb 2026 22:18:20 -0500
Subject: [PATCH 19/19] foramt

---
 .../pricetaker/design_and_operation_models.py                 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
index bf4305ffe3..f47eb0cf3d 100644
--- a/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
+++ b/idaes/apps/grid_integration/pricetaker/design_and_operation_models.py
@@ -94,11 +94,11 @@ def is_valid_startup_types(data):
     if len(data) == 0:
         # set to None instead of an empty dict.
         raise ConfigurationError("Received an empty dictionary for startup types")
-    
+
     if len(data) == 1:
         raise ConfigurationError(
             "At least two startup types must be defined for the unit/process. \n"
-            "if startup_types = {\"hot\": 4, \"warm\": 8, \"cold\": 12}, \n"
+            'if startup_types = {"hot": 4, "warm": 8, "cold": 12}, \n'
             "then when downtime is between 4 to 8 -> hot startup; \n"
             "when downtime is between 8 to 12 -> warm startup; \n"
             "when downtime is greater than 12 -> cold startup. \n"