Add lower bound for incoming transport flows

Author: gnawin

src/constraints/capacity.jl

@@ -356,7 +356,9 @@ function add_capacity_constraints!(connection, model, expressions, constraints,
     cons_name = Symbol("min_output_flows_limit_for_transport_flows_without_unit_commitment")
     table_name = :min_outgoing_flow_for_transport_flows_without_unit_commitment
 
-    # - Maximum input flows limit
+    # - Minmum output flows limit if any of the flows is transport flow
+    # - This allows negative flows but not all negative flows, so flows can pass through this asset
+    # - Holds for producers, conversion and storage assets
     attach_constraint!(
         model,
         constraints[table_name],
@@ -371,6 +373,26 @@ function add_capacity_constraints!(connection, model, expressions, constraints,
         ],
     )
 
+    # - Minmum input flows limit if any of the flows is transport flow
+    # - This allows negative flows but not all negative flows, so flows can pass through this asset
+    # - Holds for onversion and storage assets
+    cons_name = Symbol("min_input_flows_limit_for_transport_flows")
+    table_name = :min_incoming_flow_for_transport_flows
+
+    attach_constraint!(
+        model,
+        constraints[table_name],
+        cons_name,
+        [
+            @constraint(
+                model,
+                incoming_flow ≥ 0,
+                base_name = "$cons_name[$(row.asset),$(row.year),$(row.rep_period),$(row.time_block_start):$(row.time_block_end)]"
+            ) for (row, incoming_flow) in
+            zip(constraints[table_name].indices, constraints[table_name].expressions[:incoming])
+        ],
+    )
+
     return
 end
 

src/constraints/create.jl

@@ -17,6 +17,7 @@ function compute_constraints_indices(connection)
             :capacity_outgoing_simple_method_non_investable_storage_with_binary,
             :capacity_outgoing_simple_method_investable_storage_with_binary,
             :min_outgoing_flow_for_transport_flows_without_unit_commitment,
+            :min_incoming_flow_for_transport_flows,
             :limit_units_on_compact_method,
             :limit_units_on_simple_method,
             :min_output_flow_with_unit_commitment,

src/model-preparation.jl

@@ -532,6 +532,7 @@ function add_expressions_to_constraints!(connection, variables, constraints)
         :capacity_outgoing_simple_method_non_investable_storage_with_binary,
         :capacity_outgoing_simple_method_investable_storage_with_binary,
         :min_outgoing_flow_for_transport_flows_without_unit_commitment,
+        :min_incoming_flow_for_transport_flows,
     )
         @timeit to "add_expression_terms_rep_period_constraints! for $table_name" add_expression_terms_rep_period_constraints!(
             connection,

src/sql/create-constraints.sql

@@ -227,6 +227,37 @@ where
 drop sequence id
 ;
 
+create sequence id start 1
+;
+
+create table cons_min_incoming_flow_for_transport_flows as
+
+with transport_flow_info as (
+    select
+    asset.asset,
+    coalesce(
+        (select bool_or(flow.is_transport)
+         from flow
+         where flow.to_asset = asset.asset),
+         false
+    ) as incoming_flows_have_transport_flows,
+    from asset
+)
+select
+    nextval('id') as id,
+    t_high.*
+from
+    t_highest_out_flows as t_high
+    left join asset on t_high.asset = asset.asset
+    left join transport_flow_info on t_high.asset = transport_flow_info.asset
+where
+    asset.type in ('storage', 'conversion')
+    and transport_flow_info.incoming_flows_have_transport_flows
+;
+
+drop sequence id
+;
+
 create table cons_limit_units_on_compact_method as
 select
     *