Inclusion of potential for TransmissionMode emissions (#26)

* Include modeling of emissions based on initial proposal

* Changed the structure for inclusion of emissions

---------

Co-authored-by: Truls Flatberg <[email protected]>

NEWS.md

@@ -8,6 +8,12 @@
 * This approach required `EnergyModelsGeography` to include all functions and type declarations internally.
 * An extension was introduced to handle these problems.
 
+### Introduced potential for emissions of `TransmissionMode`s
+
+* As outlined in [Issue 9](https://github.com/EnergyModelsX/EnergyModelsGeography.jl/issues/9), there is a requirement for potential emissions from `TransmissionMode`s.
+* The clean approach was not achieved within a certain timeframe, hence, a limited approach is implemented based on the initial provided branches in both [`EMB`](https://github.com/EnergyModelsX/EnergyModelsBase.jl/tree/0.7/emissions) and [`EMG`](https://github.com/EnergyModelsX/EnergyModelsGeography.jl/tree/0.9/emissions).
+* The implementation is **not** tested!
+
 ## Version 0.9.1 (2024-05-24)
 
 ### Bugfix

src/constraint_functions.jl

@@ -234,3 +234,25 @@ function constraints_opex_var(m, tm::TransmissionMode, 𝒯ᴵⁿᵛ, modeltype:
         )
     end
 end
+
+"""
+    constraints_emission(m, tm::TransmissionMode, 𝒯, modeltype::EnergyModel)
+
+Function for creating the constraints on the emissions of a generic `TransmissionMode` `tm`.
+This function serves as fallback option if no other function is specified for a
+`TransmissionMode`.
+"""
+function constraints_emission(m, tm::TransmissionMode, 𝒯, modeltype::EnergyModel)
+
+    if is_bidirectional(tm)
+        @constraint(m, [t ∈ 𝒯, p_em ∈ emit_resources(tm)],
+            m[:emissions_trans][tm, t, p_em] ==
+                emission(tm, p_em, t) * (m[:trans_pos][tm, t] + m[:trans_neg][tm, t])
+        )
+    else
+        @constraint(m, [t ∈ 𝒯, p_em ∈ emit_resources(tm)],
+            m[:emissions_trans][tm, t, p_em] ==
+                emission(tm, p_em, t) * m[:trans_out][tm, t]
+        )
+    end
+end

src/model.jl

@@ -40,11 +40,15 @@ function create_model(case, modeltype::EnergyModel, m::JuMP.Model; check_timepro
     variables_trans_opex(m, 𝒯, ℳ, modeltype)
     variables_trans_capacity(m, 𝒯, ℳ, modeltype)
     variables_trans_modes(m, 𝒯, ℳ, modeltype)
+    variables_trans_emission(m, 𝒯, ℳ, 𝒫, modeltype)
 
     # Construction of constraints for areas and transmission corridors
     constraints_area(m, 𝒜, 𝒯, ℒᵗʳᵃⁿˢ, 𝒫, modeltype)
     constraints_transmission(m, 𝒯, ℳ, modeltype)
 
+    # Updates the global constraint on total emissions
+    update_total_emissions(m, 𝒯, ℳ, 𝒫, modeltype)
+
     # Updates the objective function
     update_objective(m, 𝒯, ℳ, modeltype)
 
@@ -173,6 +177,27 @@ function variables_trans_mode(m, 𝒯, ℳᴸᴾ::Vector{<:PipeLinepackSimple},
     @variable(m, linepack_stor_level[ℳᴸᴾ, 𝒯] >= 0)
 end
 
+"""
+    variables_trans_emission(m, 𝒯, ℳ, 𝒫, modeltype)
+
+Creates variables for the modeling of tranmission emissions. These variables
+are only created for transmission modes where emissions are included.
+All emission resources that are not included for a type are fixed to a value of 0.
+
+The emission variables are differentiated in:
+* `:emissions_node` - emissions of a transmission mode in an operational period,
+"""
+function variables_trans_emission(m, 𝒯, ℳ, 𝒫, modeltype)
+    ℳᵉᵐ = filter(m -> has_emissions(m), ℳ)
+    𝒫ᵉᵐ  = EMB.res_sub(𝒫, ResourceEmit)
+
+    @variable(m, emissions_trans[ℳᵉᵐ, 𝒯, 𝒫ᵉᵐ] >= 0)
+
+    # Fix of unused emission variables to avoid free variables
+    for tm ∈ ℳᵉᵐ, p_em ∈ setdiff(𝒫ᵉᵐ, emit_resources(tm)), t ∈ 𝒯
+        fix(m[:emissions_trans][tm, t, p_em], 0; force = true)
+    end
+end
 
 """
     constraints_area(m, 𝒜, 𝒯, ℒᵗʳᵃⁿˢ, 𝒫, modeltype::EnergyModel)
@@ -277,6 +302,25 @@ function update_objective(m, 𝒯, ℳ, modeltype::EnergyModel)
     @objective(m, Max, obj)
 end
 
+"""
+    update_total_emissions(m, 𝒯, ℳ, 𝒫, modeltype::EnergyModel)
+
+Update the constraints aggregating total emissions in each time period
+with contributions from transmission emissions.
+"""
+function update_total_emissions(m, 𝒯, ℳ, 𝒫, modeltype::EnergyModel)
+    ℳᵉᵐ = filter(m -> has_emissions(m), ℳ)
+    𝒫ᵉᵐ  = EMB.res_sub(𝒫, EMB.ResourceEmit)
+
+    # Modify existing constraints on total emissions by adding contribution from
+    # transmission emissions. Note the coefficient is set to -1 since the total constraint
+    # has the variables on the RHS.
+    for tm ∈ ℳᵉᵐ, p ∈ 𝒫ᵉᵐ, t ∈ 𝒯
+        JuMP.set_normalized_coefficient(m[:con_em_tot][t, p], m[:emissions_trans][tm, t, p], -1.0)
+    end
+end
+
+
 
 """
     create_transmission_mode(m, tm::TransmissionMode, 𝒯, modeltype::EnergyModel)
@@ -299,6 +343,9 @@ function create_transmission_mode(m, tm::TransmissionMode, 𝒯, modeltype::Ener
     # Call of the function for limiting the capacity to the maximum installed capacity
     constraints_capacity(m, tm, 𝒯, modeltype)
 
+    # Call of the functions for transmission emissions
+    constraints_emission(m, tm, 𝒯, modeltype)
+
     # Call of the functions for both fixed and variable OPEX constraints introduction
     constraints_opex_fixed(m, tm, 𝒯ᴵⁿᵛ, modeltype)
     constraints_opex_var(m, tm, 𝒯ᴵⁿᵛ, modeltype)

src/structures/mode.jl

@@ -2,6 +2,7 @@
 abstract type TransmissionMode end
 Base.show(io::IO, t::TransmissionMode) = print(io, "$(t.id)")
 
+
 """ A reference dynamic `TransmissionMode`.
 
 Generic representation of dynamic transmission modes, using for example truck, ship or railway transport.
@@ -279,6 +280,36 @@ Returns the directions of transmission mode `tm`.
 """
 directions(tm::TransmissionMode) = tm.directions
 
+"""
+    has_emissions(tm::TransmissionMode)
+
+Returns whether there are emissions associated with transmission mode `tm`.
+Default behaviour is no emissions.
+"""
+has_emissions(tm::TransmissionMode) = false
+
+"""
+    emit_resources(m::TransmissionMode)
+
+Returns the types of emissions associated with transmission mode `tm`.
+"""
+emit_resources(tm::TransmissionMode) = EMB.ResourceEmit[]
+
+"""
+    emission(tm::TransmissionMode, p::EMB.ResourceEmit)
+
+Returns the emission of transmission mode `tm` of a specific resource `p` as `TimeProfile`
+"""
+emission(tm::TransmissionMode, p::EMB.ResourceEmit) = 0
+
+"""
+    emission(tm::TransmissionMode, p::EMB.ResourceEmit, t)
+
+Returns the emission of transmission mode `tm` of a specific resource `p` at time period `t`
+per unit transmitted.
+"""
+emission(tm::TransmissionMode, p::EMB.ResourceEmit, t) = 0
+
 """
     consumption_rate(tm::PipeMode)