Remove unnecessary expression and move lower bound of flow variable f…

…rom src/constraints/capacity.jl (#976)

src/constraints/capacity.jl

@@ -9,18 +9,14 @@ Adds the capacity constraints for all asset types to the model
 function add_capacity_constraints!(model, variables, constraints, graph, sets)
     ## unpack from sets
     Acv = sets[:Acv]
-    Ai = sets[:Ai]
     Ap = sets[:Ap]
     As = sets[:As]
-    Asb = sets[:Asb]
     V_all = sets[:V_all]
-    Y = sets[:Y]
     accumulated_set_using_compact_method = sets[:accumulated_set_using_compact_method]
     accumulated_set_using_compact_method_lookup = sets[:accumulated_set_using_compact_method_lookup]
     accumulated_units_lookup = sets[:accumulated_units_lookup]
     decommissionable_assets_using_compact_method =
         sets[:decommissionable_assets_using_compact_method]
-    decommissionable_assets_using_simple_method = sets[:decommissionable_assets_using_simple_method]
 
     ## unpack from model
     accumulated_initial_units = model[:accumulated_initial_units]
@@ -81,13 +77,6 @@ function add_capacity_constraints!(model, variables, constraints, graph, sets)
         )
     end
 
-    # - Create accumulated investment limit for the use of binary storage method with investments
-    accumulated_investment_limit = @expression(
-        model,
-        accumulated_investment_limit[y in Y, a in Ai[y]∩Asb],
-        graph[a].investment_limit[y]
-    )
-
     # - Create capacity limit for outgoing flows with binary is_charging for storage assets
     let table_name = :capacity_outgoing_non_investable_storage_with_binary,
         cons = constraints[table_name]
@@ -160,7 +149,7 @@ function add_capacity_constraints!(model, variables, constraints, graph, sets)
                     ) *
                     (
                         graph[row.asset].capacity * accumulated_initial_units[row.asset, row.year] +
-                        accumulated_investment_limit[row.year, row.asset]
+                        graph[row.asset].investment_limit[row.year]
                     ) *
                     (1 - is_charging)
                 ) for
@@ -265,7 +254,7 @@ function add_capacity_constraints!(model, variables, constraints, graph, sets)
                     ) *
                     (
                         graph[row.asset].capacity * accumulated_initial_units[row.asset, row.year] +
-                        accumulated_investment_limit[row.year, row.asset]
+                        graph[row.asset].investment_limit[row.year]
                     ) *
                     is_charging
                 ) for
@@ -369,15 +358,4 @@ function add_capacity_constraints!(model, variables, constraints, graph, sets)
             ],
         )
     end
-
-    # - Lower limit for flows associated with assets
-    assets_with_non_negative_flows_indices = DataFrames.subset(
-        flows_indices,
-        [:from, :to] => DataFrames.ByRow(
-            (from, to) -> from in Ap || from in Acv || from in As || to in Acv || to in As,
-        ),
-    )
-    for row in eachrow(assets_with_non_negative_flows_indices)
-        JuMP.set_lower_bound(flow[row.index], 0.0)
-    end
 end

src/create-model.jl

@@ -68,7 +68,7 @@ function create_model(
     JuMP.set_string_names_on_creation(model, enable_names)
 
     ## Variables
-    @timeit to "add_flow_variables!" add_flow_variables!(model, variables)
+    @timeit to "add_flow_variables!" add_flow_variables!(connection, model, variables)
     @timeit to "add_investment_variables!" add_investment_variables!(model, graph, sets, variables)
     @timeit to "add_unit_commitment_variables!" add_unit_commitment_variables!(
         model,

src/variables/flows.jl

@@ -7,16 +7,43 @@ Adds flow variables to the optimization `model` based on data from the `variable
 The flow variables are created using the `@variable` macro for each row in the `:flows` dataframe.
 
 """
-function add_flow_variables!(model, variables)
+function add_flow_variables!(connection, model, variables)
     # Unpacking the variable indices
     flows_indices = variables[:flow].indices
+    indices = _create_flow_table(connection)
+
+    lower_bound(row) =
+        if row.from_asset_type in ("producer", "conversion", "storage") ||
+           row.to_asset_type in ("conversion", "storage")
+            0.0
+        else
+            -Inf
+        end
 
     variables[:flow].container = [
         @variable(
             model,
+            lower_bound = lower_bound(row),
             base_name = "flow[($(row.from), $(row.to)), $(row.year), $(row.rep_period), $(row.time_block_start):$(row.time_block_end)]"
-        ) for row in eachrow(flows_indices)
+        ) for row in indices
     ]
 
     return
 end
+
+function _create_flow_table(connection)
+    return DuckDB.query(
+        connection,
+        "SELECT
+            var_flow.*,
+            from_asset.type AS from_asset_type,
+            to_asset.type AS to_asset_type,
+        FROM var_flow
+        LEFT JOIN asset AS from_asset
+            ON var_flow.from = from_asset.asset
+        LEFT JOIN asset AS to_asset
+            ON var_flow.to = to_asset.asset
+        ORDER BY var_flow.index
+        ",
+    )
+end