[Fix] eELOSSByZone expr: access before initialization

CHANGELOG.md

@@ -32,6 +32,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   Previously there was a typo in this in the multistage code that led to a silent bug, which affects outputs,
   for anyone running non-myopic multistage GenX with asymmetric storage.
 - Fix computation of cumulative minimum capacity retirements in multistage GenX (#514)
+- Fix access of eELOSSByZone expr before initialization (#541)
 
 ### Changed
 - Use add_to_expression! instead of the += and -= operators for memory performance improvements (#498).

src/model/generate_model.jl

@@ -95,6 +95,9 @@ function generate_model(setup::Dict,inputs::Dict,OPTIMIZER::MOI.OptimizerWithAtt
 
 	create_empty_expression!(EP, :eGenerationByZone, (Z, T))
 
+	# Energy losses related to technologies
+	create_empty_expression!(EP, :eELOSSByZone, Z)
+
 	# Initialize Capacity Reserve Margin Expression
 	if setup["CapacityReserveMargin"] > 0
 		create_empty_expression!(EP, :eCapResMarBalance, (inputs["NCapacityReserveMargin"], T))
@@ -128,7 +131,6 @@ function generate_model(setup::Dict,inputs::Dict,OPTIMIZER::MOI.OptimizerWithAtt
 
 	co2!(EP, inputs) 
 
-
 	if setup["Reserves"] > 0
 		reserves!(EP, inputs, setup)
 	end

src/model/resources/storage/storage_all.jl

@@ -128,10 +128,9 @@ function storage_all!(EP::Model, inputs::Dict, setup::Dict)
 		end
 	end
 
-	#From CO2 Policy module
-	@expression(EP, eELOSSByZone[z=1:Z],
-		sum(EP[:eELOSS][y] for y in intersect(STOR_ALL, dfGen[dfGen[!,:Zone].==z,:R_ID]))
-	)
+	# From CO2 Policy module
+	expr = @expression(EP, [z=1:Z], sum(EP[:eELOSS][y] for y in intersect(STOR_ALL, dfGen[dfGen[!,:Zone].==z,:R_ID])))
+	add_similar_to_expression!(EP[:eELOSSByZone], expr)
 
 	# Capacity Reserve Margin policy
 	if CapacityReserveMargin > 0

src/model/resources/vre_stor/vre_stor.jl

@@ -1166,11 +1166,7 @@ function stor_vre_stor!(EP::Model, inputs::Dict, setup::Dict)
     # From CO2 Policy module
 	@expression(EP, eELOSSByZone_VRE_STOR[z=1:Z],
         sum(EP[:eELOSS_VRE_STOR][y] for y in intersect(dfVRE_STOR[(dfVRE_STOR[!,:Zone].==z),:R_ID],STOR)))
-    if !isempty(inputs["STOR_ALL"])
-        EP[:eELOSSByZone] += eELOSSByZone_VRE_STOR
-    else
-        @expression(EP, eELOSSByZone[z=1:Z], eELOSSByZone_VRE_STOR[z])
-    end
+    add_similar_to_expression!(EP[:eELOSSByZone], eELOSSByZone_VRE_STOR)
 
     ### CONSTRAINTS ###