Battery storage cost constant version 2

CHANGELOG.md

@@ -25,6 +25,11 @@ Classify the change according to the following categories:
     ### Deprecated
     ### Removed
 
+## Develop - 2024-11-03
+### Added
+- Add new **ElectricStorage** input fields **installed_cost_constant**, **replace_cost_constant** (both default to 0), and **cost_constant_replacement_year** (defaults to year 10).
+- Added new binary variable **binIncludeStorageCostConstant** which is indexed on `p.s.storage.types.elec`
+
 
 ## Develop
 ### Added
@@ -106,7 +111,7 @@ Classify the change according to the following categories:
 - Refactored various functions to ensure **ProcessHeatLoad** is processed correctly in line with other heating loads.
 - When the URDB response `energyratestructure` has a "unit" value that is not "kWh", throw an error instead of averaging rates in each energy tier.
 - Refactored heating flow constraints to be in ./src/constraints/thermal_tech_constraints.jl instead of its previous separate locations in the storage and turbine constraints.
-- Changed default Financial **owner_tax_rate_fraction** and **offtaker_tax_rate_fraction** from 0.257 to 0.26 to align with API and user manual defaults.
+- Changed default Financial **owner_tax_rate_fraction** and **offtaker_tax_rate_fraction** from 0.257 to 0.26 to align with API and user manual defaults. 
 ### Fixed
 - Updated the PV result **lifecycle_om_cost_after_tax** to account for the third-party factor for third-party ownership analyses.
 - Convert `max_electric_load_kw` to _Float64_ before passing to function `get_chp_defaults_prime_mover_size_class`

src/constraints/outage_constraints.jl

@@ -77,7 +77,8 @@ function add_outage_cost_constraints(m,p)
             m[:dvMGStorageUpgradeCost] >= p.s.financial.microgrid_upgrade_cost_fraction * m[:TotalStorageCapCosts] - (
                 p.s.financial.microgrid_upgrade_cost_fraction * p.third_party_factor * (
                     sum( p.s.storage.attr[b].net_present_cost_per_kw * p.s.storage.attr[b].max_kw for b in p.s.storage.types.elec) + 
-                    sum( p.s.storage.attr[b].net_present_cost_per_kwh * p.s.storage.attr[b].max_kwh for b in p.s.storage.types.all )
+                    sum( p.s.storage.attr[b].net_present_cost_per_kwh * p.s.storage.attr[b].max_kwh for b in p.s.storage.types.all ) +
+                    sum(p.storage.attr[b].net_present_cost_cost_constant for b in p.storage.types.elec)
                 ) * (1-m[:binMGStorageUsed])  # Big-M is capital cost of battery with max size kw and kwh
             )
         )

src/constraints/storage_constraints.jl

@@ -111,7 +111,7 @@ function add_elec_storage_dispatch_constraints(m, p, b; _n="")
         m[Symbol("dvStoragePower"*_n)][b] >= m[Symbol("dvDischargeFromStorage"*_n)][b,ts] + 
             sum(m[Symbol("dvProductionToStorage"*_n)][b, t, ts] for t in p.techs.elec)
     )
-					
+    	
     # Remove grid-to-storage as an option if option to grid charge is turned off
     if !(p.s.storage.attr[b].can_grid_charge)
         for ts in p.time_steps_with_grid
@@ -128,6 +128,16 @@ function add_elec_storage_dispatch_constraints(m, p, b; _n="")
     end
 end
 
+function add_elec_storage_cost_constant_constraints(m, p, b; _n="")
+    # Include the electric storage cost constants only if the installed_cost_constant or the replace_cost_constant is not zero
+    if p.s.storage.attr[b].installed_cost_constant != 0 || p.s.storage.attr[b].replace_cost_constant != 0
+        # If there is a battery, then the binIncludeStorageCostConstant binary must be 1
+        @constraint(m, m[Symbol("dvStorageEnergy"*_n)][b] <= p.s.storage.attr[b].max_kwh * m[Symbol("binIncludeStorageCostConstant"*_n)][b])		
+    else
+        m[Symbol("binIncludeStorageCostConstant"*_n)][b] == 0
+    end
+end 
+
 function add_hot_thermal_storage_dispatch_constraints(m, p, b; _n="")
 
     # Constraint (4j)-1: Reconcile state-of-charge for (hot) thermal storage

src/core/energy_storage/electric_storage.jl

@@ -31,7 +31,10 @@ worth factor is used in the same manner irrespective of the `maintenance_strateg
     When modeling degradation the following ElectricStorage inputs are not used:
     - `replace_cost_per_kwh`
     - `battery_replacement_year`
-    The are replaced by the `maintenance_cost_per_kwh` vector.
+    - `installed_cost_constant`
+    - `replace_cost_constant`
+    - `cost_constant_replacement_year`
+    They are replaced by the `maintenance_cost_per_kwh` vector.
     Inverter replacement costs and inverter replacement year should still be used to model scheduled replacement of inverter.
 
 !!! note
@@ -140,6 +143,7 @@ The following shows how one would use the degradation model in REopt via the [Sc
 }
 ```
 Note that not all of the above inputs are necessary. When not providing `calendar_fade_coefficient` for example the default value will be used.
+
 """
 
 Base.@kwdef mutable struct Degradation
@@ -167,12 +171,15 @@ end
     soc_min_applies_during_outages::Bool = false
     soc_init_fraction::Float64 = off_grid_flag ? 1.0 : 0.5
     can_grid_charge::Bool = off_grid_flag ? false : true
-    installed_cost_per_kw::Real = 910.0
-    installed_cost_per_kwh::Real = 455.0
+    installed_cost_per_kw::Real = 910.0 # Cost of power components (e.g., inverter and BOS) 
+    installed_cost_per_kwh::Real = 455.0 # Cost of energy components (e.g., battery pack)
+    installed_cost_constant::Real = 0.0 # "+c" constant cost that is added to total ElectricStorage installed costs if a battery is included. Accounts for costs not expected to scale with power or energy capacity.
     replace_cost_per_kw::Real = 715.0
     replace_cost_per_kwh::Real = 318.0
+    replace_cost_constant::Real = 0.0
     inverter_replacement_year::Int = 10
     battery_replacement_year::Int = 10
+    cost_constant_replacement_year::Int = 10
     macrs_option_years::Int = 7
     macrs_bonus_fraction::Float64 = 0.6
     macrs_itc_reduction::Float64 = 0.5
@@ -204,10 +211,13 @@ Base.@kwdef struct ElectricStorageDefaults
     can_grid_charge::Bool = off_grid_flag ? false : true
     installed_cost_per_kw::Real = 910.0
     installed_cost_per_kwh::Real = 455.0
+    installed_cost_constant::Real = 0.0
     replace_cost_per_kw::Real = 715.0
     replace_cost_per_kwh::Real = 318.0
+    replace_cost_constant::Real = 0.0
     inverter_replacement_year::Int = 10
     battery_replacement_year::Int = 10
+    cost_constant_replacement_year::Int = 10
     macrs_option_years::Int = 7
     macrs_bonus_fraction::Float64 = 0.6
     macrs_itc_reduction::Float64 = 0.5
@@ -245,10 +255,13 @@ struct ElectricStorage <: AbstractElectricStorage
     can_grid_charge::Bool
     installed_cost_per_kw::Real
     installed_cost_per_kwh::Real
+    installed_cost_constant::Real
     replace_cost_per_kw::Real
     replace_cost_per_kwh::Real
+    replace_cost_constant::Real
     inverter_replacement_year::Int
     battery_replacement_year::Int
+    cost_constant_replacement_year::Int
     macrs_option_years::Int
     macrs_bonus_fraction::Float64
     macrs_itc_reduction::Float64
@@ -260,6 +273,7 @@ struct ElectricStorage <: AbstractElectricStorage
     grid_charge_efficiency::Float64
     net_present_cost_per_kw::Real
     net_present_cost_per_kwh::Real
+    net_present_cost_cost_constant::Real
     model_degradation::Bool
     degradation::Degradation
     minimum_avg_soc_fraction::Float64
@@ -318,11 +332,39 @@ struct ElectricStorage <: AbstractElectricStorage
 
         net_present_cost_per_kwh -= s.total_rebate_per_kwh
 
+        net_present_cost_cost_constant = effective_cost(;
+            itc_basis = s.installed_cost_constant,
+            replacement_cost = s.cost_constant_replacement_year >= f.analysis_years ? 0.0 : s.replace_cost_constant,
+            replacement_year = s.cost_constant_replacement_year,
+            discount_rate = f.owner_discount_rate_fraction,
+            tax_rate = f.owner_tax_rate_fraction,
+            itc = s.total_itc_fraction,
+            macrs_schedule = s.macrs_option_years == 7 ? f.macrs_seven_year : f.macrs_five_year,
+            macrs_bonus_fraction = s.macrs_bonus_fraction,
+            macrs_itc_reduction = s.macrs_itc_reduction
+
+        )
+
         if haskey(d, :degradation)
             degr = Degradation(;dictkeys_tosymbols(d[:degradation])...)
         else
             degr = Degradation()
         end
+
+        # copy the replace_costs in case we need to change them
+        replace_cost_per_kw = s.replace_cost_per_kw 
+        replace_cost_per_kwh = s.replace_cost_per_kwh
+        replace_cost_constant = s.replace_cost_constant
+        if s.model_degradation
+            if haskey(d, :replace_cost_per_kw) && d[:replace_cost_per_kw] != 0.0 || 
+                haskey(d, :replace_cost_per_kwh) && d[:replace_cost_per_kwh] != 0.0 ||
+                haskey(d, :replace_cost_constant) && d[:replace_cost_constant] != 0.0
+                @warn "Setting ElectricStorage replacement costs to zero. Using degradation.maintenance_cost_per_kwh instead."
+            end
+            replace_cost_per_kw = 0.0
+            replace_cost_per_kwh = 0.0
+            replace_cost_constant = 0.0
+        end
 
         return new(
             s.min_kw,
@@ -338,10 +380,13 @@ struct ElectricStorage <: AbstractElectricStorage
             s.can_grid_charge,
             s.installed_cost_per_kw,
             s.installed_cost_per_kwh,
+            s.installed_cost_constant,
             replace_cost_per_kw,
             replace_cost_per_kwh,
+            replace_cost_constant,
             s.inverter_replacement_year,
             s.battery_replacement_year,
+            s.cost_constant_replacement_year,
             s.macrs_option_years,
             s.macrs_bonus_fraction,
             s.macrs_itc_reduction,
@@ -353,6 +398,7 @@ struct ElectricStorage <: AbstractElectricStorage
             s.grid_charge_efficiency,
             net_present_cost_per_kw,
             net_present_cost_per_kwh,
+            net_present_cost_cost_constant,
             s.model_degradation,
             degr,
             s.minimum_avg_soc_fraction,

src/core/reopt.jl

@@ -209,6 +209,7 @@ function build_reopt!(m::JuMP.AbstractModel, p::REoptInputs)
 			@constraint(m, m[:dvStorageEnergy][b] == 0)
 			@constraint(m, [ts in p.time_steps], m[:dvDischargeFromStorage][b, ts] == 0)
 			if b in p.s.storage.types.elec
+				@constraint(m, m[:binIncludeStorageCostConstant][b] == 0)
 				@constraint(m, m[:dvStoragePower][b] == 0)
 				@constraint(m, [ts in p.time_steps], m[:dvGridToStorage][b, ts] == 0)
 				@constraint(m, [t in p.techs.elec, ts in p.time_steps_with_grid],
@@ -236,6 +237,7 @@ function build_reopt!(m::JuMP.AbstractModel, p::REoptInputs)
 			add_general_storage_dispatch_constraints(m, p, b)
 			if b in p.s.storage.types.elec
 				add_elec_storage_dispatch_constraints(m, p, b)
+				add_elec_storage_cost_constant_constraints(m, p, b)
 			elseif b in p.s.storage.types.hot
 				add_hot_thermal_storage_dispatch_constraints(m, p, b)
 			elseif b in p.s.storage.types.cold
@@ -407,7 +409,8 @@ function build_reopt!(m::JuMP.AbstractModel, p::REoptInputs)
 
 	@expression(m, TotalStorageCapCosts, p.third_party_factor * (
 		sum( p.s.storage.attr[b].net_present_cost_per_kw * m[:dvStoragePower][b] for b in p.s.storage.types.elec) + 
-		sum( p.s.storage.attr[b].net_present_cost_per_kwh * m[:dvStorageEnergy][b] for b in p.s.storage.types.all )
+		sum( p.s.storage.attr[b].net_present_cost_per_kwh * m[:dvStorageEnergy][b] for b in p.s.storage.types.all ) +
+		sum( p.s.storage.attr[b].net_present_cost_cost_constant * m[:binIncludeStorageCostConstant][b] for b in p.s.storage.types.elec)
 	))
 
 	@expression(m, TotalPerUnitSizeOMCosts, p.third_party_factor * p.pwf_om *
@@ -623,6 +626,7 @@ function add_variables!(m::JuMP.AbstractModel, p::REoptInputs)
 		dvPeakDemandMonth[p.months, 1:p.s.electric_tariff.n_monthly_demand_tiers] >= 0  # Peak electrical power demand during month m [kW]
 		MinChargeAdder >= 0
         binGHP[p.ghp_options], Bin  # Can be <= 1 if require_ghp_purchase=0, and is ==1 if require_ghp_purchase=1
+		binIncludeStorageCostConstant[p.s.storage.types.elec], Bin # 0 if no battery is included, 1 if battery is included
 	end
 
 	if !isempty(p.techs.gen)  # Problem becomes a MILP

src/core/reopt_multinode.jl

@@ -14,6 +14,7 @@ function add_variables!(m::JuMP.AbstractModel, ps::AbstractVector{REoptInputs{T}
 	dvs_idx_on_storagetypes = String[
 		"dvStoragePower",
 		"dvStorageEnergy",
+		"binIncludeStorageCostConstant"
 	]
 	dvs_idx_on_storagetypes_time_steps = String[
 		"dvDischargeFromStorage"
@@ -75,6 +76,7 @@ function add_variables!(m::JuMP.AbstractModel, ps::AbstractVector{REoptInputs{T}
 		m[Symbol(ex_name)] = @expression(m, p.third_party_factor * 
 			sum(p.s.storage.attr[b].net_present_cost_per_kw * m[Symbol("dvStoragePower"*_n)][b] for b in p.s.storage.types.elec)
 			+ sum(p.s.storage.attr[b].net_present_cost_per_kwh * m[Symbol("dvStorageEnergy"*_n)][b] for b in p.s.storage.types.all)
+			+ sum(p.s.storage.attr[b].net_present_cost_cost_constant * m[Symbol("binIncludeStorageCostConstant"*_n)][b] for b in p.s.storage.types.elec)
 		)
 
 		ex_name = "TotalPerUnitSizeOMCosts"*_n
@@ -120,11 +122,15 @@ function build_reopt!(m::JuMP.AbstractModel, ps::AbstractVector{REoptInputs{T}})
                             m[Symbol("dvProductionToStorage"*_n)][b, t, ts] == 0)
                 @constraint(m, [ts in p.time_steps], m[Symbol("dvDischargeFromStorage"*_n)][b, ts] == 0)
                 @constraint(m, [ts in p.time_steps], m[Symbol("dvGridToStorage"*_n)][b, ts] == 0)
+				if b in p.s.storage.types.elec
+					@constraint(m, m[Symbol("binIncludeStorageCostConstant"*_n)][b] == 0)
+				end
             else
                 add_storage_size_constraints(m, p, b; _n=_n)
                 add_general_storage_dispatch_constraints(m, p, b; _n=_n)
 				if b in p.s.storage.types.elec
 					add_elec_storage_dispatch_constraints(m, p, b; _n=_n)
+					add_elec_storage_cost_constant_constraints(m, p, b; _n=_n)
 				elseif b in p.s.storage.types.hot
 					add_hot_thermal_storage_dispatch_constraints(m, p, b; _n=_n)
 				elseif b in p.s.storage.types.cold

src/results/electric_storage.jl

@@ -32,7 +32,8 @@ function add_electric_storage_results(m::JuMP.AbstractModel, p::REoptInputs, d::
         r["storage_to_load_series_kw"] = round.(value.(discharge), digits=3)
 
         r["initial_capital_cost"] = r["size_kwh"] * p.s.storage.attr[b].installed_cost_per_kwh +
-            r["size_kw"] * p.s.storage.attr[b].installed_cost_per_kw
+            r["size_kw"] * p.s.storage.attr[b].installed_cost_per_kw +
+            p.s.storage.attr[b].installed_cost_constant
 
         if p.s.storage.attr[b].model_degradation
             r["state_of_health"] = value.(m[:SOH]).data / value.(m[:dvStorageEnergy])["ElectricStorage"];

src/results/financial.jl

@@ -146,7 +146,8 @@ function initial_capex(m::JuMP.AbstractModel, p::REoptInputs; _n="")
     for b in p.s.storage.types.elec
         if p.s.storage.attr[b].max_kw > 0
             initial_capex += p.s.storage.attr[b].installed_cost_per_kw * value.(m[Symbol("dvStoragePower"*_n)])[b] + 
-                p.s.storage.attr[b].installed_cost_per_kwh * value.(m[Symbol("dvStorageEnergy"*_n)])[b]
+                p.s.storage.attr[b].installed_cost_per_kwh * value.(m[Symbol("dvStorageEnergy"*_n)])[b] +
+                (p.s.storage.attr[b].installed_cost_constant * value.(m[Symbol("binIncludeStorageCostConstant"*_n)])[b])
         end
     end
 
@@ -233,12 +234,20 @@ function replacement_costs_future_and_present(m::JuMP.AbstractModel, p::REoptInp
         else
             future_cost_storage = p.s.storage.attr[b].replace_cost_per_kwh * value.(m[Symbol("dvStorageEnergy"*_n)])[b]
         end
-        future_cost += future_cost_inverter + future_cost_storage
+        if p.s.storage.attr[b].cost_constant_replacement_year >= p.s.financial.analysis_years
+            future_cost_cost_constant = 0
+        else
+            future_cost_cost_constant = p.s.storage.attr[b].replace_cost_constant * value.(m[Symbol("binIncludeStorageCostConstant"*_n)])[b]
+        end
+
+        future_cost += future_cost_inverter + future_cost_storage + future_cost_cost_constant
 
         present_cost += future_cost_inverter * (1 - p.s.financial.owner_tax_rate_fraction) / 
             ((1 + p.s.financial.owner_discount_rate_fraction)^p.s.storage.attr[b].inverter_replacement_year)
         present_cost += future_cost_storage * (1 - p.s.financial.owner_tax_rate_fraction) / 
             ((1 + p.s.financial.owner_discount_rate_fraction)^p.s.storage.attr[b].battery_replacement_year)
+        present_cost += future_cost_cost_constant * (1 - p.s.financial.owner_tax_rate_fraction) / 
+            ((1 + p.s.financial.owner_discount_rate_fraction)^p.s.storage.attr[b].cost_constant_replacement_year)  
     end
 
     if !isempty(p.techs.gen) # Generator replacement 

src/results/proforma.jl

@@ -74,10 +74,11 @@ function proforma_results(p::REoptInputs, d::Dict)
         storage = p.s.storage.attr["ElectricStorage"]
         total_kw = d["ElectricStorage"]["size_kw"]
         total_kwh = d["ElectricStorage"]["size_kwh"]
-        capital_cost = total_kw * storage.installed_cost_per_kw + total_kwh * storage.installed_cost_per_kwh
+        capital_cost = total_kw * storage.installed_cost_per_kw + total_kwh * storage.installed_cost_per_kwh + storage.installed_cost_constant
         battery_replacement_year = storage.battery_replacement_year
-        battery_replacement_cost = -1 * ((total_kw * storage.replace_cost_per_kw) + (
-                    total_kwh * storage.replace_cost_per_kwh))
+        battery_replacement_cost = -1 * ((total_kw * storage.replace_cost_per_kw) + 
+                    (total_kwh * storage.replace_cost_per_kwh) + 
+                    storage.replace_cost_constant)
         m.om_series += [yr != battery_replacement_year ? 0 : battery_replacement_cost for yr in 1:years]
 
         # storage only has cbi in the API