From 94e481081295ba67063b807cf3a51cf5dc13fb6f Mon Sep 17 00:00:00 2001
From: Jose Daniel Lara <jdlara@berkeley.edu>
Date: Tue, 5 Sep 2023 11:10:01 -0600
Subject: [PATCH] add FF slack to objective function

---
 src/feedforward/feedforward_arguments.jl | 5 +++++
 test/test_basic_model_structs.jl         | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/src/feedforward/feedforward_arguments.jl b/src/feedforward/feedforward_arguments.jl
index ea85b62627..520fc5f8fb 100644
--- a/src/feedforward/feedforward_arguments.jl
+++ b/src/feedforward/feedforward_arguments.jl
@@ -79,7 +79,12 @@ function _add_feedforward_slack_variables!(container::OptimizationContainer,
                 base_name = "$(T)_$(U)_{$(name), $(t)}",
                 lower_bound = 0.0
             )
+            add_to_objective_invariant_expression!(
+            container,
+            variable_container[name, t] * BALANCE_SLACK_COST,
+        )
         end
+
     end
     return
 end
diff --git a/test/test_basic_model_structs.jl b/test/test_basic_model_structs.jl
index 6928b5e196..e456761b9f 100644
--- a/test/test_basic_model_structs.jl
+++ b/test/test_basic_model_structs.jl
@@ -69,12 +69,14 @@ end
         component_type = RenewableDispatch,
         source = ActivePowerVariable,
         affected_values = [OnStatusParameter],
+        use_slacks = true,
     )
 
     @test_throws ErrorException LowerBoundFeedforward(
         component_type = RenewableDispatch,
         source = ActivePowerVariable,
         affected_values = [OnStatusParameter],
+        use_slacks = true,
     )
 
     @test_throws ErrorException SemiContinuousFeedforward(