Reformat source code

Implement plant storage
Implement plant expansion
18 changed files with 755 additions and 253 deletions
--- a/docs/src/format.md
+++ b/docs/src/format.md
@ -152,6 +152,7 @@ detail.
 | `disposal cost ($/tonne)`      | Dictionary mapping the name of each output product to the cost of disposing it at the plant.                                                 |
 | `disposal limit (tonne)`       | Dictionary mapping the name of each output product to the maximum amount allowed to be disposed of at the plant. May be `null` if unlimited. |
 | `capacities`                   | List describing what plant sizes are allowed, and their characteristics.                                                                     |
+| `initial capacity (tonne)`     | Capacity already available. If the plant has not been built yet, this should be `0`.                                                         |

 The entries in the `capacities` list should be dictionaries with the following
 keys:
@ -160,9 +161,8 @@ keys:
 | :---------------------------------- | :-------------------------------------------------------------------------------------------------- |
 | `size (tonne)`                      | The size of the plant.                                                                              |
 | `opening cost ($)`                  | The cost to open a plant of this size.                                                              |
-| `fixed operating cost ($)`          | The cost to keep the plant open, even if the plant doesn't process anything. Must be a time series. |
-| `variable operating cost ($/tonne)` | The cost that the plant incurs to process each tonne of input. Must be a time series.               |
-| `initial capacity (tonne)`          | Capacity already available. If the plant has not been built yet, this should be `0`.                |
+| `fixed operating cost ($)`          | The cost to keep the plant open, even if the plant doesn't process anything.                        |
+| `variable operating cost ($/tonne)` | The cost that the plant incurs to process each tonne of input. Must be the same for all capacities. |

 ```json
 {
--- a/docs/src/problem.md
+++ b/docs/src/problem.md
@ -5,7 +5,7 @@
 The mathematical model employed by RELOG is based on three main components:

 1. **Products and Materials:** Inputs and outputs for both manufacturing and
-   recycling plants. This include raw materials, whether virgin or recovered,
+   recycling plants. This includes raw materials, whether virgin or recovered,
   and final products, whether new or at their end-of-life. Each product has
   associated transportation parameters, such as costs, energy and emissions.

@ -49,28 +49,35 @@ The mathematical model employed by RELOG is based on three main components:

 ## Constants

-| Symbol                      | Description                                                                                                                                                                                                      | Unit           |
-| :-------------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------- |
-| $K^{\text{dist}}_{uv}$      | Distance between plants/centers $u$ and $v$                                                                                                                                                                      | km             |
-| $K^\text{cap}_{p}$          | Capacity of plant $p$, if the plant is open                                                                                                                                                                      | tonne          |
-| $K^\text{disp-limit}_{mt}$  | Maximum amount of material $m$ that can be disposed of (globally) at time $t$                                                                                                                                    | tonne          |
-| $K^\text{disp-limit}_{mut}$ | Maximum amount of material $m$ that can be disposed of at plant/center $u$ at time $t$                                                                                                                           | tonne          |
-| $K^\text{em-limit}_{gt}$    | Maximum amount of greenhouse gas $g$ allowed to be emitted (globally) at time $t$                                                                                                                                | tonne          |
-| $K^\text{em-plant}_{gpt}$   | Amount of greenhouse gas $g$ released by plant $p$ at time $t$ for each tonne of input material processed                                                                                                        | tonne/tonne    |
-| $K^\text{em-tr}_{gmt}$      | Amount of greenhouse gas $g$ released by transporting 1 tonne of material $m$ over one km at time $t$                                                                                                            | tonne/km-tonne |
-| $K^\text{mix}_{pmt}$        | If plant $p$ receives one tonne of input material at time $t$, then $K^\text{mix}_{pmt}$ is the amount of product $m$ in this mix. Must be between zero and one, and the sum of these amounts must equal to one. | tonne          |
-| $K^\text{out-fix}_{cmt}$    | Fixed amount of material $m$ collected at center $m$ at time $t$                                                                                                                                                 | \$/tonne       |
-| $K^\text{out-var-len}_{cm}$ | Length of the $K^\text{out-var}_{c,m,*}$ vector.                                                                                                                                                                 | --             |
-| $K^\text{out-var}_{c,m,i}$  | Factor used to calculate variable amount of material $m$ collected at center $m$. See `eq_z_collected` for more details.                                                                                         | --             |
-| $K^\text{output}_{pmt}$     | Amount of material $m$ produced by plant $p$ at time $t$ for each tonne of input material processed                                                                                                              | tonne          |
-| $R^\text{collect}_{cmt}$    | Cost of collecting material $m$ at center $c$ at time $t$                                                                                                                                                        | \$/tonne       |
-| $R^\text{disp}_{umt}$       | Cost to dispose of material at plant/center $u$ at time $t$                                                                                                                                                      | \$/tonne       |
-| $R^\text{em}_{gt}$          | Penalty cost per tonne of greenhouse gas $g$ emitted at time $t$                                                                                                                                                 | \$/tonne       |
-| $R^\text{fix}_{ut}$         | Fixed operating cost for plant/center $u$ at time $t$                                                                                                                                                            | \$             |
-| $R^\text{open}_{pt}$        | Cost to open plant $p$ at time $t$                                                                                                                                                                               | \$             |
-| $R^\text{rev}_{ct}$         | Revenue for selling the input product of center $c$ at this center at time $t$                                                                                                                                   | \$/tonne       |
-| $R^\text{tr}_{mt}$          | Cost to send material $m$ at time $t$                                                                                                                                                                            | \$/km-tonne    |
-| $R^\text{var}_{pt}$         | Cost to process one tonne of input material at plant $p$ at time $t$                                                                                                                                             | \$/tonne       |
+| Symbol                        | Description                                                                                                                                                                                                      | Unit           |
+| :---------------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------- |
+| $K^{\text{dist}}_{uv}$        | Distance between plants/centers $u$ and $v$                                                                                                                                                                      | km             |
+| $K^\text{cap-init}_p$         | Initial capacity of plant $p$                                                                                                                                                                                    | tonne          |
+| $K^\text{cap-max}_p$          | Maximum capacity of plant $p$                                                                                                                                                                                    | tonne          |
+| $K^\text{cap-min}_p$          | Minimum capacity of plant $p$                                                                                                                                                                                    | tonne          |
+| $K^\text{disp-limit}_{mt}$    | Maximum amount of material $m$ that can be disposed of (globally) at time $t$                                                                                                                                    | tonne          |
+| $K^\text{disp-limit}_{mut}$   | Maximum amount of material $m$ that can be disposed of at plant/center $u$ at time $t$                                                                                                                           | tonne          |
+| $K^\text{em-limit}_{gt}$      | Maximum amount of greenhouse gas $g$ allowed to be emitted (globally) at time $t$                                                                                                                                | tonne          |
+| $K^\text{em-plant}_{gpt}$     | Amount of greenhouse gas $g$ released by plant $p$ at time $t$ for each tonne of input material processed                                                                                                        | tonne/tonne    |
+| $K^\text{em-tr}_{gmt}$        | Amount of greenhouse gas $g$ released by transporting 1 tonne of material $m$ over one km at time $t$                                                                                                            | tonne/km-tonne |
+| $K^\text{mix}_{pmt}$          | If plant $p$ receives one tonne of input material at time $t$, then $K^\text{mix}_{pmt}$ is the amount of product $m$ in this mix. Must be between zero and one, and the sum of these amounts must equal to one. | tonne          |
+| $K^\text{out-fix}_{cmt}$      | Fixed amount of material $m$ collected at center $c$ at time $t$                                                                                                                                                 | tonne          |
+| $K^\text{out-var-len}_{cm}$   | Length of the $K^\text{out-var}_{c,m,*}$ vector.                                                                                                                                                                 | --             |
+| $K^\text{out-var}_{cmi}$      | Factor used to calculate variable amount of material $m$ collected at center $c$. See `eq_z_collected` for more details.                                                                                         | --             |
+| $K^\text{output}_{pmt}$       | Amount of material $m$ produced by plant $p$ at time $t$ for each tonne of input material processed                                                                                                              | tonne          |
+| $K^\text{storage-limit}_{pm}$ | Maximum amount of material $m$ that can be stored at plant $p$ at any time                                                                                                                                       | tonne          |
+| $R^\text{collect}_{cmt}$      | Cost of collecting material $m$ at center $c$ at time $t$                                                                                                                                                        | \$/tonne       |
+| $R^\text{disp}_{umt}$         | Cost to dispose of material at plant/center $u$ at time $t$                                                                                                                                                      | \$/tonne       |
+| $R^\text{em}_{gt}$            | Penalty cost per tonne of greenhouse gas $g$ emitted at time $t$                                                                                                                                                 | \$/tonne       |
+| $R^\text{expand}_{pt}$        | Cost to increase capacity of plant $p$ at time $t$                                                                                                                                                               | \$/tonne       |
+| $R^\text{fix-exp}_{pt}$       | Increase in fixed operational cost for plant $p$ at time $t$ for every additional tonne of capacity                                                                                                              | \$/tonne       |
+| $R^\text{fix-min}_{pt}$       | Fixed operating cost for plant $p$ at time $t$ at minimum capacity                                                                                                                                               | \$             |
+| $R^\text{fix}_{ct}$           | Fixed operating cost for center $c$ at time $t$                                                                                                                                                                  | \$             |
+| $R^\text{open}_{pt}$          | Cost to open plant $p$ at time $t$, at minimum capacity                                                                                                                                                          | \$             |
+| $R^\text{rev}_{ct}$           | Revenue for selling the input product of center $c$ at this center at time $t$                                                                                                                                   | \$/tonne       |
+| $R^\text{storage}_{pmt}$      | Cost to store one tonne of material $m$ at plant $p$ at time $t$ for one year                                                                                                                                    | \$/tonne       |
+| $R^\text{tr}_{mt}$            | Cost to send material $m$ at time $t$                                                                                                                                                                            | \$/km-tonne    |
+| $R^\text{var}_{pt}$           | Cost to process one tonne of input material at plant $p$ at time $t$                                                                                                                                             | \$/tonne       |

 ## Decision variables

@ -78,16 +85,19 @@ The mathematical model employed by RELOG is based on three main components:
 | :--------------------------- | :------------------------------------------- | :------------------------------------------------------------------------------------------------------ | :----- |
 | $x_{pt}$                     | `x[p.name, t]`                               | One if plant $p$ is operational at time $t$                                                             | binary |
 | $y_{uvmt}$                   | `y[u.name, v.name, m.name, t]`               | Amount of product $m$ sent from plant/center $u$ to plant/center $v$ at time $t$                        | tonne  |
+| $z^{\text{exp}}_{pt}$        | `z_exp[p.name, t]`                           | Extra capacity installed at plant $p$ at time $t$ above the minimum capacity                            | tonne  |
 | $z^{\text{collected}}_{cmt}$ | `z_collected[c.name, m.name, t]`             | Amount of material $m$ collected by center $c$ at time $t$                                              | tonne  |
 | $z^{\text{disp}}_{umt}$      | `z_disp[u.name, m.name, t]`                  | Amount of product $m$ disposed of at plant/center $u$ at time $t$                                       | tonne  |
-| $z^{\text{input}}_{ut}$      | `z_input[u.name, t]`                         | Total plant/center input at time $t$                                                                    | tonne  |
-| $z^{\text{prod}}_{umt}$      | `z_prod[u.name, m.name, t]`                  | Amount of product $m$ produced by plant/center $u$ at time $t$                                          | tonne  |
-| $z^{\text{em-tr}}_{guvmt}$   | `z_em_tr[g.name, u.name, v.name, m.name, t]` | Amount of greenhouse gas $g$ released at time $t$ due to transportation of material $m$ from $u$ to $v$ | tonne  |
 | $z^{\text{em-plant}}_{gpt}$  | `z_em_plant[g.name, p.name, t]`              | Amount of greenhouse gas $g$ released by plant $p$ at time $t$                                          | tonne  |
+| $z^{\text{em-tr}}_{guvmt}$   | `z_em_tr[g.name, u.name, v.name, m.name, t]` | Amount of greenhouse gas $g$ released at time $t$ due to transportation of material $m$ from $u$ to $v$ | tonne  |
+| $z^{\text{input}}_{ut}$      | `z_input[u.name, t]`                         | Total amount received by plant/center $u$ at time $t$                                                   | tonne  |
+| $z^{\text{prod}}_{umt}$      | `z_prod[u.name, m.name, t]`                  | Amount of product $m$ produced by plant/center $u$ at time $t$                                          | tonne  |
+| $z^{\text{storage}}_{pmt}$   | `z_storage[p.name, m.name, t]`               | Amount of input material $m$ stored at plant $p$ at the end of time $t$                                 | tonne  |
+| $z^{\text{process}}_{pt}$    | `z_process[p.name, t]`                       | Total amount of input material processed by plant $p$ at time $t$                                       | tonne  |

 ## Objective function

-The goals is to minimize a linear objective function with the following terms:
+The goal is to minimize a linear objective function with the following terms:

 - Transportation costs, which depend on transportation distance
  $K^{\text{dist}}_{uv}$ and product-specific factor $R^\text{tr}_{mt}$:
@ -131,7 +141,9 @@ The goals is to minimize a linear objective function with the following terms:
 \sum_{p \in P} \sum_{m \in M^+_p} \sum_{t \in T} R^\text{disp}_{pmt} z^\text{disp}_{pmt}
 ```

- Plant opening cost:
+- Plant opening cost, incurred when the plant goes from non-operational at time
+  $t-1$ to operational at time $t$. Never incurred if the plant is initially
+  open:

 ```math
 \sum_{p \in P} \sum_{t \in T} R^\text{open}_{pt} \left(
@ -140,10 +152,20 @@ The goals is to minimize a linear objective function with the following terms:
 ```

 - Plant fixed operating cost, incurred for every time period, regardless of
-  input or output amounts, as long as the plant is operational:
+  input or output amounts, as long as the plant is operational. Depends on the
+  size of the plant:

 ```math
-\sum_{p \in P} \sum_{t \in T} R^\text{fix}_{pt} x_{pt}
+\sum_{p \in P} \sum_{t \in T} \left(
+    R^\text{fix-min}_{pt} x_{pt} +
+    R^\text{fix-exp}_{pt} z^\text{exp}_{pt}
+\right)
+```
+
+- Plant expansion cost, incurred whenever plant capacity increases:
+
+```math
+\sum_{p \in P} \sum_{t \in T} R^\text{expand}_{pt} \left(z^\text{exp}_{pt} - z^\text{exp}_{p,t-1} \right)
 ```

 - Plant variable operating cost, incurred for each tonne of input material
@ -153,6 +175,12 @@ The goals is to minimize a linear objective function with the following terms:
 \sum_{p \in P} \sum_{(u,m) \in E^-(p)} \sum_{t \in T} R^\text{var}_{pt} y_{upmt}
 ```

+- Plant storage cost, incurred for each tonne of material stored at the plant:
+
+```math
+\sum_{p \in P} \sum_{m \in M^-_p} \sum_{t \in T} R^\text{storage}_{pmt} z^{\text{storage}}_{pmt}
+```
+
 - Emissions penalty cost, incurred for each tonne of greenhouse gas emitted:

 ```math
@ -160,6 +188,7 @@ The goals is to minimize a linear objective function with the following terms:
  \sum_{p \in P} z^{\text{em-plant}}_{gpt} + \sum_{(u,v,m) \in E} z^{\text{em-tr}}_{guvmt}
 \right)
 ```
+
 ## Constraints

 - Definition of plant input (`eq_z_input[p.name, t]`):
@ -171,13 +200,22 @@ The goals is to minimize a linear objective function with the following terms:
 \end{align*}
 ```

- Plant input mix must have correct proportion
-  (`eq_input_mix[p.name, m.name, t]`):
+- Definition of plant processing (`eq_z_process[p.name, t]`):
+
+```math
+\begin{align*}
+& z^{\text{process}}_{pt} = z^{\text{input}}_{pt} + \sum_{m \in M^-_p} \left(z^{\text{storage}}_{p,m,t-1} - z^{\text{storage}}_{pmt}\right)
+& \forall p \in P, t \in T
+\end{align*}
+```
+
+- Plant processing mix must have correct proportion
+  (`eq_process_mix[p.name, m.name, t]`):

 ```math
 \begin{align*}
-& \sum_{u : (u,m) \in E^-(p)} y_{upmt}
-= K^\text{mix}_{pmt} z^{\text{input}}_{pt}
+& \sum_{u : (u,m) \in E^-(p)} y_{upmt} + z^{\text{storage}}_{p,m,t-1} - z^{\text{storage}}_{pmt}
+= K^\text{mix}_{pmt} z^{\text{process}}_{pt}
 & \forall p \in P, m \in M^-_p, t \in T
 \end{align*}
 ```
@ -186,7 +224,7 @@ The goals is to minimize a linear objective function with the following terms:

 ```math
 \begin{align*}
-& z^\text{prod}_{pmt} = K^\text{output}_{pmt} z^\text{input}_{pt}
+& z^\text{prod}_{pmt} = K^\text{output}_{pmt} z^{\text{process}}_{pt}
 & \forall p \in P, m \in M^+_p, t \in T
 \end{align*}
 ```
@ -201,16 +239,56 @@ The goals is to minimize a linear objective function with the following terms:
 \end{align*}
 ```

- Plants have a maximum capacity; furthermore, if the plant is not open, its
-  capacity is zero (`eq_capacity[p.name,t]`)
+- Plant can only be expanded if the plant is open, and up to a certain amount
+  (`eq_exp_ub[p.name, t]`):

 ```math
 \begin{align*}
-& z^\text{input}_{pt} \leq K^\text{cap}_p x_{pt}
+& z^\text{exp}_{pt} \leq \left(K^\text{cap-max}_p - K^\text{cap-min}_p) x_{pt}
 & \forall p \in P, t \in T
 \end{align*}
 ```

+- Plant is initially open if initial capacity is positive:
+
+```math
+\begin{align*}
+& x_{p,0} = \begin{cases}
+    0 & \text{ if } K^\text{cap-init}_p = 0 \\
+    1 & \text{otherwise}
+\end{cases}
+& \forall p \in P
+\end{align*}
+```
+
+- Calculation of initial plant expansion:
+
+```math
+\begin{align*}
+& z^\text{exp}_{p,0} = K^\text{cap-init}_p - K^\text{cap-min}_p
+& \forall p \in P
+\end{align*}
+```
+
+- Plants cannot process more than their current capacity
+  (`eq_process_limit[p.name,t]`)
+
+```math
+\begin{align*}
+& z^\text{process}_{pt} \leq K^\text{cap-min}_p x_{pt} + z^\text{exp}_{pt}
+& \forall p \in P, t \in T
+\end{align*}
+```
+
+- Storage limit at the plants (`eq_storage_limit[p.name, m.name, t]`):
+
+```math
+\begin{align*}
+& z^{\text{storage}}_{pmt} \leq K^\text{storage-limit}_{pm}
+& \forall p \in P, m \in M^-_p, t \in T
+\end{align*}
+```
+
 - Disposal limit at the plants (`eq_disposal_limit[p.name, m.name, t]`):

 ```math
@ -280,7 +358,8 @@ The goals is to minimize a linear objective function with the following terms:
 \end{align*}
 ```

- Computation of transportation emissions (`eq_emission_tr[g.name, u.name, v.name, m.name, t`):
+- Computation of transportation emissions
+  (`eq_emission_tr[g.name, u.name, v.name, m.name, t]`):

 ```math
 \begin{align*}
@ -293,7 +372,7 @@ The goals is to minimize a linear objective function with the following terms:

 ```math
 \begin{align*}
-& z^{\text{em-plant}}_{gpt} = \sum_{(u,m) \in E^-(p)} K^\text{em-plant}_{gpt} y_{upmt}
+& z^{\text{em-plant}}_{gpt} = K^\text{em-plant}_{gpt} z^{\text{process}}_{pt}
 & \forall g \in G, p \in P, t \in T
 \end{align*}
 ```
@ -306,3 +385,22 @@ The goals is to minimize a linear objective function with the following terms:
 & \forall g \in G, t \in T
 \end{align*}
 ```
+
+- All stored materials must be processed by the end of the time horizon
+  (`eq_storage_final[p.name, m.name]`):
+
+```math
+\begin{align*}
+& z^{\text{storage}}_{p,m,t^{max}} = 0
+& \forall p \in P, m \in M^-_p
+\end{align*}
+```
+
+- Initial storage is zero (`eq_storage_initial[p.name, m.name]`):
+
+```math
+\begin{align*}
+& z^{\text{storage}}_{p,m,0} = 0
+& \forall p \in P, m \in M^-_p
+\end{align*}
+```
--- a/src/RELOG.jl
+++ b/src/RELOG.jl
@ -1,6 +1,12 @@
 module RELOG

-_round(x::Number) = round(x, digits = 5)
+function _round(x::Number)
+    if abs(x) < 1e-5
+        return 0
+    else
+        return round(x, digits = 5)
+    end
+end

 include("instance/structs.jl")
 include("instance/parse.jl")
--- a/src/instance/parse.jl
+++ b/src/instance/parse.jl
@ -110,6 +110,32 @@ function parse(json)::Instance
            )
        end

+        # Validate capacity count and duplicate if needed
+        if length(capacities) == 0
+            error("Plant '$name' must have at least one capacity defined")
+        elseif length(capacities) == 1
+            # Duplicate the single capacity
+            push!(capacities, capacities[1])
+        elseif length(capacities) > 2
+            error(
+                "Plant '$name' cannot have more than 2 capacities, got $(length(capacities))",
+            )
+        end
+
+        # Validate capacity sizes are non-decreasing
+        if capacities[1].size > capacities[2].size
+            error(
+                "Plant '$name' capacity sizes must be non-decreasing: $(capacities[1].size) > $(capacities[2].size)",
+            )
+        end
+
+        # Validate variable operating costs are the same
+        if capacities[1].var_operating_cost != capacities[2].var_operating_cost
+            error(
+                "Plant '$name' variable operating costs must be the same across all capacities",
+            )
+        end
+
        plant = Plant(;
            name,
            latitude,
--- a/src/model/build.jl
+++ b/src/model/build.jl
@ -1,5 +1,17 @@
+# RELOG: Reverse Logistics Optimization
+# Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
+# Released under the modified BSD license. See COPYING.md for more details.
+
 using JuMP

+R_expand(p::Plant, t::Int) =
+    (p.capacities[2].opening_cost[t] - p.capacities[1].opening_cost[t]) /
+    (p.capacities[2].size - p.capacities[1].size)
+
+R_fix_exp(p::Plant, t::Int) =
+    (p.capacities[2].fix_operating_cost[t] - p.capacities[1].fix_operating_cost[t]) /
+    (p.capacities[2].size - p.capacities[1].size)
+
 function build_model(instance::Instance; optimizer, variable_names::Bool = false)
    model = JuMP.Model(optimizer)
    centers = instance.centers
@ -8,6 +20,15 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
    T = 1:instance.time_horizon
    model.ext[:instance] = instance

+    # Constants
+    # -------------------------------------------------------------------------
+    K_cap_min = Dict(p => p.capacities[1].size for p in plants)
+    K_cap_max = Dict(p => p.capacities[2].size for p in plants)
+    R_open = Dict((p, t) => p.capacities[1].opening_cost[t] for p in plants for t in T)
+    R_fix_min =
+        Dict((p, t) => p.capacities[1].fix_operating_cost[t] for p in plants for t in T)
+
+
    # Transportation edges
    # -------------------------------------------------------------------------

@ -112,12 +133,38 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
        z_input[c.name, t] = @variable(model, lower_bound = 0)
    end

+    # Plant expansion
+    z_exp = _init(model, :z_exp)
+    for p in plants
+        z_exp[p.name, 0] = max(0, p.initial_capacity - K_cap_min[p])
+    end
+    for p in plants, t in T
+        z_exp[p.name, t] = @variable(model, lower_bound = 0)
+    end
+
    # Total amount collected by the center
    z_collected = _init(model, :z_collected)
    for c in centers, m in c.outputs, t in T
        z_collected[c.name, m.name, t] = @variable(model, lower_bound = 0)
    end

+    # Amount of input material stored at plant at end of time period
+    z_storage = _init(model, :z_storage)
+    for p in plants
+        for m in keys(p.input_mix)
+            z_storage[p.name, m.name, 0] = 0  # Initial storage is zero
+        end
+    end
+    for p in plants, m in keys(p.input_mix), t in T
+        z_storage[p.name, m.name, t] = @variable(model, lower_bound = 0)
+    end
+
+    # Total amount of input material processed by plant
+    z_process = _init(model, :z_process)
+    for p in plants, t in T
+        z_process[p.name, t] = @variable(model, lower_bound = 0)
+    end
+
    # Transportation emissions by greenhouse gas
    z_em_tr = _init(model, :z_em_tr)
    for (p1, p2, m) in E, t in T, g in keys(m.tr_emissions)
@ -171,16 +218,18 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false

    # Plants: Opening cost
    for p in plants, t in T
-        add_to_expression!(
-            obj,
-            p.capacities[1].opening_cost[t],
-            (x[p.name, t] - x[p.name, t-1]),
-        )
+        add_to_expression!(obj, R_open[p, t], (x[p.name, t] - x[p.name, t-1]))
    end

    # Plants: Fixed operating cost
    for p in plants, t in T
-        add_to_expression!(obj, p.capacities[1].fix_operating_cost[t], x[p.name, t])
+        add_to_expression!(obj, R_fix_min[p, t], x[p.name, t])
+        add_to_expression!(obj, R_fix_exp(p, t), z_exp[p.name, t])
+    end
+
+    # Plants: Expansion cost
+    for p in plants, t in T
+        add_to_expression!(obj, R_expand(p, t), z_exp[p.name, t] - z_exp[p.name, t-1])
    end

    # Plants: Variable operating cost
@ -192,6 +241,11 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
        )
    end

+    # Plants: Storage cost
+    for p in plants, m in keys(p.storage_cost), t in T
+        add_to_expression!(obj, p.storage_cost[m][t], z_storage[p.name, m.name, t])
+    end
+
    # Emissions penalty cost
    for emission in instance.emissions, t in T
        # Plant emissions penalty
@ -231,13 +285,27 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
        )
    end

-    # Plants: Must meet input mix
-    eq_input_mix = _init(model, :eq_input_mix)
+    # Plants: Definition of total processing amount
+    eq_z_process = _init(model, :eq_z_process)
+    for p in plants, t in T
+        eq_z_process[p.name, t] = @constraint(
+            model,
+            z_process[p.name, t] ==
+            z_input[p.name, t] + sum(
+                z_storage[p.name, m.name, t-1] - z_storage[p.name, m.name, t] for
+                m in keys(p.input_mix)
+            )
+        )
+    end
+
+    # Plants: Processing mix must have correct proportion
+    eq_process_mix = _init(model, :eq_process_mix)
    for p in plants, m in keys(p.input_mix), t in T
-        eq_input_mix[p.name, m.name, t] = @constraint(
+        eq_process_mix[p.name, m.name, t] = @constraint(
            model,
-            sum(y[src.name, p.name, m.name, t] for (src, m2) in E_in[p] if m == m2) ==
-            z_input[p.name, t] * p.input_mix[m][t]
+            sum(y[src.name, p.name, m.name, t] for (src, m2) in E_in[p] if m == m2) +
+            z_storage[p.name, m.name, t-1] - z_storage[p.name, m.name, t] ==
+            z_process[p.name, t] * p.input_mix[m][t]
        )
    end

@ -246,7 +314,7 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
    for p in plants, m in keys(p.output), t in T
        eq_z_prod[p.name, m.name, t] = @constraint(
            model,
-            z_prod[p.name, m.name, t] == z_input[p.name, t] * p.output[m][t]
+            z_prod[p.name, m.name, t] == z_process[p.name, t] * p.output[m][t]
        )
    end

@ -261,11 +329,22 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
        )
    end

-    # Plants: Capacity limit
-    eq_capacity = _init(model, :eq_capacity)
+    # Plants: Expansion upper bound
+    eq_exp_ub = _init(model, :eq_exp_ub)
+    for p in plants, t in T
+        eq_exp_ub[p.name, t] = @constraint(
+            model,
+            z_exp[p.name, t] <= (K_cap_max[p] - K_cap_min[p]) * x[p.name, t]
+        )
+    end
+
+    # Plants: Processing limit
+    eq_process_limit = _init(model, :eq_process_limit)
    for p in plants, t in T
-        eq_capacity[p.name, t] =
-            @constraint(model, z_input[p.name, t] <= p.capacities[1].size * x[p.name, t])
+        eq_process_limit[p.name, t] = @constraint(
+            model,
+            z_process[p.name, t] <= K_cap_min[p] * x[p.name, t] + z_exp[p.name, t]
+        )
    end

    # Plants: Disposal limit
@ -361,11 +440,26 @@ function build_model(instance::Instance; optimizer, variable_names::Bool = false
    for p in plants, t in T, g in keys(p.emissions)
        eq_emission_plant[g, p.name, t] = @constraint(
            model,
-            z_em_plant[g, p.name, t] ==
-            p.emissions[g][t] * sum(y[src.name, p.name, m.name, t] for (src, m) in E_in[p])
+            z_em_plant[g, p.name, t] == p.emissions[g][t] * z_process[p.name, t]
        )
    end

+    # Storage limit at plants
+    eq_storage_limit = _init(model, :eq_storage_limit)
+    for p in plants, m in keys(p.storage_limit), t in T
+        if isfinite(p.storage_limit[m][t])
+            eq_storage_limit[p.name, m.name, t] =
+                @constraint(model, z_storage[p.name, m.name, t] <= p.storage_limit[m][t])
+        end
+    end
+
+    # All stored materials must be processed by end of time horizon
+    eq_storage_final = _init(model, :eq_storage_final)
+    for p in plants, m in keys(p.input_mix)
+        eq_storage_final[p.name, m.name] =
+            @constraint(model, z_storage[p.name, m.name, instance.time_horizon] == 0)
+    end
+
    # Global emissions limit
    eq_emission_limit = _init(model, :eq_emission_limit)
    for emission in instance.emissions, t in T
--- a/src/reports/plants.jl
+++ b/src/reports/plants.jl
@ -15,9 +15,13 @@ function plants_report(model)::DataFrame
    df."year" = Int[]
    df."operational?" = Bool[]
    df."input amount (tonne)" = Float64[]
+    df."stored amount (tonne)" = Float64[]
+    df."processed amount (tonne)" = Float64[]
    df."opening cost (\$)" = Float64[]
    df."fixed operating cost (\$)" = Float64[]
    df."variable operating cost (\$)" = Float64[]
+    df."expansion cost (\$)" = Float64[]
+    df."storage cost (\$)" = Float64[]

    plants = model.ext[:instance].plants
    T = 1:model.ext[:instance].time_horizon
@ -25,21 +29,36 @@ function plants_report(model)::DataFrame
    for p in plants, t in T
        operational = JuMP.value(model[:x][p.name, t]) > 0.5
        input = value(model[:z_input][p.name, t])
+        processed = value(model[:z_process][p.name, t])

-        # Opening cost
+        # Calculate total stored amount across all input materials
+        stored = sum(value(model[:z_storage][p.name, m.name, t]) for m in keys(p.input_mix))
+
+        # Calculate total storage cost
+        storage_cost = sum(
+            p.storage_cost[m][t] * value(model[:z_storage][p.name, m.name, t]) for
+            m in keys(p.storage_cost)
+        )
+
+        var_operating_cost = input * p.capacities[1].var_operating_cost[t]
        opening_cost = 0
+        curr_capacity = 0
+        expansion_cost = 0
+        fix_operating_cost = 0
+
        if value(model[:x][p.name, t]) > 0.5 && value(model[:x][p.name, t-1]) < 0.5
            opening_cost = p.capacities[1].opening_cost[t]
        end

-        # Plant size
-        curr_capacity = 0
        if operational
-            curr_capacity = p.capacities[1].size
+            curr_expansion = JuMP.value(model[:z_exp][p.name, t])
+            prev_expansion = JuMP.value(model[:z_exp][p.name, t-1])
+            curr_capacity = p.capacities[1].size + curr_expansion
+            expansion_cost = R_expand(p, t) * (curr_expansion - prev_expansion)
+            fix_operating_cost =
+                p.capacities[1].fix_operating_cost[t] + R_fix_exp(p, t) * curr_expansion
        end

-        fix_operating_cost = (operational ? p.capacities[1].fix_operating_cost[t] : 0)
-        var_operating_cost = input * p.capacities[1].var_operating_cost[t]
        push!(
            df,
            Dict(
@ -51,9 +70,53 @@ function plants_report(model)::DataFrame
                "year" => t,
                "operational?" => operational,
                "input amount (tonne)" => _round(input),
+                "stored amount (tonne)" => _round(stored),
+                "processed amount (tonne)" => _round(processed),
                "opening cost (\$)" => _round(opening_cost),
                "fixed operating cost (\$)" => _round(fix_operating_cost),
                "variable operating cost (\$)" => _round(var_operating_cost),
+                "expansion cost (\$)" => _round(expansion_cost),
+                "storage cost (\$)" => _round(storage_cost),
+            ),
+        )
+    end
+    return df
+end
+
+function plant_inputs_report(model)::DataFrame
+    df = DataFrame()
+    df."plant" = String[]
+    df."latitude" = Float64[]
+    df."longitude" = Float64[]
+    df."input product" = String[]
+    df."year" = Int[]
+    df."amount received (tonne)" = Float64[]
+    df."current storage level (tonne)" = Float64[]
+    df."storage limit (tonne)" = Float64[]
+    df."storage cost (\$)" = Float64[]
+
+    plants = model.ext[:instance].plants
+    T = 1:model.ext[:instance].time_horizon
+
+    for p in plants, m in keys(p.input_mix), t in T
+        amount_received = sum(
+            value(model[:y][src.name, p.name, m.name, t]) for
+            (src, prod) in model.ext[:E_in][p] if prod == m
+        )
+        storage_level = value(model[:z_storage][p.name, m.name, t])
+        storage_cost = p.storage_cost[m][t] * storage_level
+        push!(
+            df,
+            Dict(
+                "plant" => p.name,
+                "latitude" => p.latitude,
+                "longitude" => p.longitude,
+                "input product" => m.name,
+                "year" => t,
+                "amount received (tonne)" => _round(amount_received),
+                "current storage level (tonne)" => _round(storage_level),
+                "storage limit (tonne)" => _round(p.storage_limit[m][t]),
+                "storage cost (\$)" => _round(storage_cost),
            ),
        )
    end
@ -104,7 +167,7 @@ function plant_emissions_report(model)::DataFrame
    df."longitude" = Float64[]
    df."emission" = String[]
    df."year" = Int[]
-    df."input amount (tonne)" = Float64[]
+    df."processed amount (tonne)" = Float64[]
    df."emission factor (tonne/tonne)" = Float64[]
    df."emissions amount (tonne)" = Float64[]

@ -112,9 +175,9 @@ function plant_emissions_report(model)::DataFrame
    T = 1:model.ext[:instance].time_horizon

    for p in plants, t in T, g in keys(p.emissions)
-        input_amount = JuMP.value(model[:z_input][p.name, t])
-        input_amount > 1e-3 || continue
-        emissions = JuMP.value(model[:z_plant_em][g, p.name, t])
+        processed_amount = JuMP.value(model[:z_process][p.name, t])
+        processed_amount > 1e-3 || continue
+        emissions = JuMP.value(model[:z_em_plant][g, p.name, t])
        emission_factor = p.emissions[g][t]
        push!(
            df,
@ -124,7 +187,7 @@ function plant_emissions_report(model)::DataFrame
                "longitude" => p.longitude,
                "emission" => g,
                "year" => t,
-                "input amount (tonne)" => _round(input_amount),
+                "processed amount (tonne)" => _round(processed_amount),
                "emission factor (tonne/tonne)" => _round(emission_factor),
                "emissions amount (tonne)" => _round(emissions),
            ),
@ -134,6 +197,8 @@ function plant_emissions_report(model)::DataFrame
 end

 write_plants_report(solution, filename) = CSV.write(filename, plants_report(solution))
+write_plant_inputs_report(solution, filename) =
+    CSV.write(filename, plant_inputs_report(solution))
 write_plant_outputs_report(solution, filename) =
    CSV.write(filename, plant_outputs_report(solution))
 write_plant_emissions_report(solution, filename) =
--- a/src/reports/transportation.jl
+++ b/src/reports/transportation.jl
@ -73,7 +73,7 @@ function transportation_emissions_report(model)::DataFrame
        amount > 1e-3 || continue
        distance = distances[p1, p2, m]
        emission_factor = m.tr_emissions[g][t]
-        emissions = value(model[:z_tr_em][g, p1.name, p2.name, m.name, t])
+        emissions = value(model[:z_em_tr][g, p1.name, p2.name, m.name, t])
        push!(
            df,
            Dict(
--- a/test/fixtures/boat_example.jl
+++ b/test/fixtures/boat_example.jl
@ -173,6 +173,7 @@ function run_boat_example()
    mkpath(fixture("boat_example"))
    write_to_file(model, fixture("boat_example/model.lp"))
    RELOG.write_plants_report(model, fixture("boat_example/plants.csv"))
+    RELOG.write_plant_inputs_report(model, fixture("boat_example/plant_inputs.csv"))
    RELOG.write_plant_outputs_report(model, fixture("boat_example/plant_outputs.csv"))
    RELOG.write_plant_emissions_report(model, fixture("boat_example/plant_emissions.csv"))
    RELOG.write_centers_report(model, fixture("boat_example/centers.csv"))
--- a/test/fixtures/boat_example/center_outputs.csv
+++ b/test/fixtures/boat_example/center_outputs.csv
@ -1,27 +1,27 @@
 center,latitude,longitude,output product,year,amount collected (tonne),amount disposed (tonne),disposal limit (tonne),collection cost ($),disposal cost ($)
-NailFactory (Chicago),41.881832,-87.623177,Nail,1,1.0,-0.0,Inf,1000.0,-0.0
+NailFactory (Chicago),41.881832,-87.623177,Nail,1,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Chicago),41.881832,-87.623177,Nail,2,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Chicago),41.881832,-87.623177,Nail,3,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Chicago),41.881832,-87.623177,Nail,4,1.0,0.0,Inf,1000.0,0.0
-NailFactory (Chicago),41.881832,-87.623177,Nail,5,1.0,-0.0,Inf,1000.0,-0.0
+NailFactory (Chicago),41.881832,-87.623177,Nail,5,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Phoenix),33.448376,-112.074036,Nail,1,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Phoenix),33.448376,-112.074036,Nail,2,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Phoenix),33.448376,-112.074036,Nail,3,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Phoenix),33.448376,-112.074036,Nail,4,1.0,0.0,Inf,1000.0,0.0
-NailFactory (Phoenix),33.448376,-112.074036,Nail,5,1.0,-0.0,Inf,1000.0,-0.0
+NailFactory (Phoenix),33.448376,-112.074036,Nail,5,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Dallas),32.776664,-96.796988,Nail,1,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Dallas),32.776664,-96.796988,Nail,2,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Dallas),32.776664,-96.796988,Nail,3,1.0,0.0,Inf,1000.0,0.0
 NailFactory (Dallas),32.776664,-96.796988,Nail,4,1.0,0.0,Inf,1000.0,0.0
-NailFactory (Dallas),32.776664,-96.796988,Nail,5,1.0,-0.0,Inf,1000.0,-0.0
+NailFactory (Dallas),32.776664,-96.796988,Nail,5,1.0,0.0,Inf,1000.0,0.0
 Forest (Chicago),41.881832,-87.623177,Wood,1,100.0,100.0,Inf,0.0,0.0
-Forest (Chicago),41.881832,-87.623177,Wood,2,100.0,100.0,Inf,-0.0,0.0
-Forest (Chicago),41.881832,-87.623177,Wood,3,100.0,100.0,Inf,-0.0,0.0
-Forest (Chicago),41.881832,-87.623177,Wood,4,100.0,100.0,Inf,-0.0,0.0
+Forest (Chicago),41.881832,-87.623177,Wood,2,100.0,100.0,Inf,0.0,0.0
+Forest (Chicago),41.881832,-87.623177,Wood,3,100.0,100.0,Inf,0.0,0.0
+Forest (Chicago),41.881832,-87.623177,Wood,4,100.0,100.0,Inf,0.0,0.0
 Forest (Chicago),41.881832,-87.623177,Wood,5,100.0,100.0,Inf,0.0,0.0
 Forest (Phoenix),33.448376,-112.074036,Wood,1,100.0,100.0,Inf,0.0,0.0
-Forest (Phoenix),33.448376,-112.074036,Wood,2,100.0,100.0,Inf,-0.0,0.0
-Forest (Phoenix),33.448376,-112.074036,Wood,3,100.0,100.0,Inf,-0.0,0.0
+Forest (Phoenix),33.448376,-112.074036,Wood,2,100.0,100.0,Inf,0.0,0.0
+Forest (Phoenix),33.448376,-112.074036,Wood,3,100.0,100.0,Inf,0.0,0.0
 Forest (Phoenix),33.448376,-112.074036,Wood,4,100.0,100.0,Inf,0.0,0.0
 Forest (Phoenix),33.448376,-112.074036,Wood,5,100.0,100.0,Inf,0.0,0.0
 Forest (Dallas),32.776664,-96.796988,Wood,1,100.0,43.0,Inf,14250.0,0.0
@ -33,7 +33,7 @@ Retail (Chicago),41.881832,-87.623177,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
 Retail (Chicago),41.881832,-87.623177,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
 Retail (Chicago),41.881832,-87.623177,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
 Retail (Chicago),41.881832,-87.623177,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
-Retail (Chicago),41.881832,-87.623177,UsedBoat,5,0.0,0.0,0.0,-0.0,0.0
+Retail (Chicago),41.881832,-87.623177,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
 Retail (New York City),40.712776,-74.005974,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
 Retail (New York City),40.712776,-74.005974,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
 Retail (New York City),40.712776,-74.005974,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
@ -44,31 +44,31 @@ Retail (Los Angeles),34.052235,-118.243683,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
 Retail (Los Angeles),34.052235,-118.243683,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
 Retail (Los Angeles),34.052235,-118.243683,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
 Retail (Los Angeles),34.052235,-118.243683,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
-Retail (Houston),29.760427,-95.369804,UsedBoat,1,-0.0,0.0,0.0,0.0,0.0
-Retail (Houston),29.760427,-95.369804,UsedBoat,2,-0.0,0.0,0.0,-0.0,0.0
-Retail (Houston),29.760427,-95.369804,UsedBoat,3,-0.0,0.0,0.0,-0.0,0.0
+Retail (Houston),29.760427,-95.369804,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
+Retail (Houston),29.760427,-95.369804,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
+Retail (Houston),29.760427,-95.369804,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
 Retail (Houston),29.760427,-95.369804,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
 Retail (Houston),29.760427,-95.369804,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
 Retail (Phoenix),33.448376,-112.074036,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
-Retail (Phoenix),33.448376,-112.074036,UsedBoat,2,-0.0,0.0,0.0,-0.0,0.0
-Retail (Phoenix),33.448376,-112.074036,UsedBoat,3,-0.0,0.0,0.0,-0.0,0.0
-Retail (Phoenix),33.448376,-112.074036,UsedBoat,4,-0.0,0.0,0.0,-0.0,0.0
+Retail (Phoenix),33.448376,-112.074036,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
+Retail (Phoenix),33.448376,-112.074036,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
+Retail (Phoenix),33.448376,-112.074036,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
 Retail (Phoenix),33.448376,-112.074036,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
 Retail (Philadelphia),39.952583,-75.165222,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
 Retail (Philadelphia),39.952583,-75.165222,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
 Retail (Philadelphia),39.952583,-75.165222,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
 Retail (Philadelphia),39.952583,-75.165222,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
 Retail (Philadelphia),39.952583,-75.165222,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
-Retail (San Antonio),29.424122,-98.493629,UsedBoat,1,-0.0,0.0,0.0,-0.0,0.0
-Retail (San Antonio),29.424122,-98.493629,UsedBoat,2,-0.0,0.0,0.0,-0.0,0.0
+Retail (San Antonio),29.424122,-98.493629,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
+Retail (San Antonio),29.424122,-98.493629,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
 Retail (San Antonio),29.424122,-98.493629,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
 Retail (San Antonio),29.424122,-98.493629,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
-Retail (San Antonio),29.424122,-98.493629,UsedBoat,5,-0.0,0.0,0.0,-0.0,0.0
+Retail (San Antonio),29.424122,-98.493629,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
 Retail (San Diego),32.715736,-117.161087,UsedBoat,1,0.0,0.0,0.0,0.0,0.0
 Retail (San Diego),32.715736,-117.161087,UsedBoat,2,0.0,0.0,0.0,0.0,0.0
 Retail (San Diego),32.715736,-117.161087,UsedBoat,3,0.0,0.0,0.0,0.0,0.0
 Retail (San Diego),32.715736,-117.161087,UsedBoat,4,0.0,0.0,0.0,0.0,0.0
-Retail (San Diego),32.715736,-117.161087,UsedBoat,5,-0.0,0.0,0.0,-0.0,0.0
+Retail (San Diego),32.715736,-117.161087,UsedBoat,5,0.0,0.0,0.0,0.0,0.0
 Retail (Dallas),32.776664,-96.796988,UsedBoat,1,6.31579,0.0,0.0,631.57895,0.0
 Retail (Dallas),32.776664,-96.796988,UsedBoat,2,22.93629,0.0,0.0,2293.62881,0.0
 Retail (Dallas),32.776664,-96.796988,UsedBoat,3,31.7714,0.0,0.0,3177.13952,0.0
--- a/test/fixtures/boat_example/centers.csv
+++ b/test/fixtures/boat_example/centers.csv
@ -29,53 +29,53 @@ Forest (Dallas),32.776664,-96.796988,2,,0.0,0.0,0.0
 Forest (Dallas),32.776664,-96.796988,3,,0.0,0.0,0.0
 Forest (Dallas),32.776664,-96.796988,4,,0.0,0.0,0.0
 Forest (Dallas),32.776664,-96.796988,5,,0.0,0.0,0.0
-Retail (Chicago),41.881832,-87.623177,1,NewBoat,-0.0,0.0,125000.0
-Retail (Chicago),41.881832,-87.623177,2,NewBoat,-0.0,0.0,125000.0
+Retail (Chicago),41.881832,-87.623177,1,NewBoat,0.0,0.0,125000.0
+Retail (Chicago),41.881832,-87.623177,2,NewBoat,0.0,0.0,125000.0
 Retail (Chicago),41.881832,-87.623177,3,NewBoat,0.0,0.0,125000.0
 Retail (Chicago),41.881832,-87.623177,4,NewBoat,0.0,0.0,125000.0
 Retail (Chicago),41.881832,-87.623177,5,NewBoat,0.0,0.0,125000.0
-Retail (New York City),40.712776,-74.005974,1,NewBoat,-0.0,0.0,125000.0
-Retail (New York City),40.712776,-74.005974,2,NewBoat,-0.0,0.0,125000.0
-Retail (New York City),40.712776,-74.005974,3,NewBoat,-0.0,0.0,125000.0
+Retail (New York City),40.712776,-74.005974,1,NewBoat,0.0,0.0,125000.0
+Retail (New York City),40.712776,-74.005974,2,NewBoat,0.0,0.0,125000.0
+Retail (New York City),40.712776,-74.005974,3,NewBoat,0.0,0.0,125000.0
 Retail (New York City),40.712776,-74.005974,4,NewBoat,0.0,0.0,125000.0
 Retail (New York City),40.712776,-74.005974,5,NewBoat,0.0,0.0,125000.0
-Retail (Los Angeles),34.052235,-118.243683,1,NewBoat,-0.0,0.0,125000.0
-Retail (Los Angeles),34.052235,-118.243683,2,NewBoat,-0.0,0.0,125000.0
-Retail (Los Angeles),34.052235,-118.243683,3,NewBoat,-0.0,0.0,125000.0
+Retail (Los Angeles),34.052235,-118.243683,1,NewBoat,0.0,0.0,125000.0
+Retail (Los Angeles),34.052235,-118.243683,2,NewBoat,0.0,0.0,125000.0
+Retail (Los Angeles),34.052235,-118.243683,3,NewBoat,0.0,0.0,125000.0
 Retail (Los Angeles),34.052235,-118.243683,4,NewBoat,0.0,0.0,125000.0
 Retail (Los Angeles),34.052235,-118.243683,5,NewBoat,0.0,0.0,125000.0
-Retail (Houston),29.760427,-95.369804,1,NewBoat,-0.0,-0.0,125000.0
-Retail (Houston),29.760427,-95.369804,2,NewBoat,-0.0,0.0,125000.0
-Retail (Houston),29.760427,-95.369804,3,NewBoat,-0.0,0.0,125000.0
+Retail (Houston),29.760427,-95.369804,1,NewBoat,0.0,0.0,125000.0
+Retail (Houston),29.760427,-95.369804,2,NewBoat,0.0,0.0,125000.0
+Retail (Houston),29.760427,-95.369804,3,NewBoat,0.0,0.0,125000.0
 Retail (Houston),29.760427,-95.369804,4,NewBoat,0.0,0.0,125000.0
 Retail (Houston),29.760427,-95.369804,5,NewBoat,0.0,0.0,125000.0
-Retail (Phoenix),33.448376,-112.074036,1,NewBoat,-0.0,0.0,125000.0
-Retail (Phoenix),33.448376,-112.074036,2,NewBoat,-0.0,-0.0,125000.0
-Retail (Phoenix),33.448376,-112.074036,3,NewBoat,-0.0,0.0,125000.0
+Retail (Phoenix),33.448376,-112.074036,1,NewBoat,0.0,0.0,125000.0
+Retail (Phoenix),33.448376,-112.074036,2,NewBoat,0.0,0.0,125000.0
+Retail (Phoenix),33.448376,-112.074036,3,NewBoat,0.0,0.0,125000.0
 Retail (Phoenix),33.448376,-112.074036,4,NewBoat,0.0,0.0,125000.0
 Retail (Phoenix),33.448376,-112.074036,5,NewBoat,0.0,0.0,125000.0
-Retail (Philadelphia),39.952583,-75.165222,1,NewBoat,-0.0,0.0,125000.0
-Retail (Philadelphia),39.952583,-75.165222,2,NewBoat,-0.0,0.0,125000.0
-Retail (Philadelphia),39.952583,-75.165222,3,NewBoat,-0.0,0.0,125000.0
+Retail (Philadelphia),39.952583,-75.165222,1,NewBoat,0.0,0.0,125000.0
+Retail (Philadelphia),39.952583,-75.165222,2,NewBoat,0.0,0.0,125000.0
+Retail (Philadelphia),39.952583,-75.165222,3,NewBoat,0.0,0.0,125000.0
 Retail (Philadelphia),39.952583,-75.165222,4,NewBoat,0.0,0.0,125000.0
 Retail (Philadelphia),39.952583,-75.165222,5,NewBoat,0.0,0.0,125000.0
-Retail (San Antonio),29.424122,-98.493629,1,NewBoat,-0.0,-0.0,125000.0
-Retail (San Antonio),29.424122,-98.493629,2,NewBoat,-0.0,0.0,125000.0
+Retail (San Antonio),29.424122,-98.493629,1,NewBoat,0.0,0.0,125000.0
+Retail (San Antonio),29.424122,-98.493629,2,NewBoat,0.0,0.0,125000.0
 Retail (San Antonio),29.424122,-98.493629,3,NewBoat,0.0,0.0,125000.0
 Retail (San Antonio),29.424122,-98.493629,4,NewBoat,0.0,0.0,125000.0
-Retail (San Antonio),29.424122,-98.493629,5,NewBoat,-0.0,0.0,125000.0
-Retail (San Diego),32.715736,-117.161087,1,NewBoat,-0.0,0.0,125000.0
-Retail (San Diego),32.715736,-117.161087,2,NewBoat,-0.0,0.0,125000.0
-Retail (San Diego),32.715736,-117.161087,3,NewBoat,-0.0,0.0,125000.0
+Retail (San Antonio),29.424122,-98.493629,5,NewBoat,0.0,0.0,125000.0
+Retail (San Diego),32.715736,-117.161087,1,NewBoat,0.0,0.0,125000.0
+Retail (San Diego),32.715736,-117.161087,2,NewBoat,0.0,0.0,125000.0
+Retail (San Diego),32.715736,-117.161087,3,NewBoat,0.0,0.0,125000.0
 Retail (San Diego),32.715736,-117.161087,4,NewBoat,0.0,0.0,125000.0
-Retail (San Diego),32.715736,-117.161087,5,NewBoat,-0.0,0.0,125000.0
+Retail (San Diego),32.715736,-117.161087,5,NewBoat,0.0,0.0,125000.0
 Retail (Dallas),32.776664,-96.796988,1,NewBoat,63.15789,757894.73684,125000.0
 Retail (Dallas),32.776664,-96.796988,2,NewBoat,71.46814,857617.72853,125000.0
 Retail (Dallas),32.776664,-96.796988,3,NewBoat,75.8857,910628.37148,125000.0
 Retail (Dallas),32.776664,-96.796988,4,NewBoat,76.90434,922852.03459,125000.0
 Retail (Dallas),32.776664,-96.796988,5,NewBoat,77.27087,927250.44516,125000.0
-Retail (San Jose),37.338208,-121.886329,1,NewBoat,-0.0,0.0,125000.0
-Retail (San Jose),37.338208,-121.886329,2,NewBoat,-0.0,0.0,125000.0
-Retail (San Jose),37.338208,-121.886329,3,NewBoat,-0.0,0.0,125000.0
+Retail (San Jose),37.338208,-121.886329,1,NewBoat,0.0,0.0,125000.0
+Retail (San Jose),37.338208,-121.886329,2,NewBoat,0.0,0.0,125000.0
+Retail (San Jose),37.338208,-121.886329,3,NewBoat,0.0,0.0,125000.0
 Retail (San Jose),37.338208,-121.886329,4,NewBoat,0.0,0.0,125000.0
 Retail (San Jose),37.338208,-121.886329,5,NewBoat,0.0,0.0,125000.0
--- a/test/fixtures/boat_example/plant_emissions.csv
+++ b/test/fixtures/boat_example/plant_emissions.csv
@ -1,4 +1,4 @@
-plant,latitude,longitude,emission,year,input amount (tonne),emission factor (tonne/tonne),emissions amount (tonne)
+plant,latitude,longitude,emission,year,processed amount (tonne),emission factor (tonne/tonne),emissions amount (tonne)
 BoatFactory (Dallas),32.776664,-96.796988,CO2,1,63.15789,5.0,315.78947
 BoatFactory (Dallas),32.776664,-96.796988,CO2,2,71.46814,5.0,357.34072
 BoatFactory (Dallas),32.776664,-96.796988,CO2,3,75.8857,5.0,379.42849
--- a/test/fixtures/boat_example/plant_inputs.csv
+++ b/test/fixtures/boat_example/plant_inputs.csv
@ -0,0 +1,151 @@
+plant,latitude,longitude,input product,year,amount received (tonne),current storage level (tonne),storage limit (tonne),storage cost ($)
+BoatFactory (Chicago),41.881832,-87.623177,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,Nail,5,0.0,0.0,1.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Wood,1,60.0,0.0,5.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Wood,2,67.89474,0.0,5.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Wood,3,72.09141,0.0,5.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Wood,4,73.05912,0.0,5.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Wood,5,73.40733,0.0,5.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Nail,1,3.15789,0.0,1.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Nail,2,3.57341,0.0,1.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Nail,3,3.79428,0.0,1.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Nail,4,3.84522,0.0,1.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,Nail,5,3.86354,0.0,1.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Wood,1,0.0,0.0,5.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Wood,2,0.0,0.0,5.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Wood,3,0.0,0.0,5.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Wood,4,0.0,0.0,5.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Wood,5,0.0,0.0,5.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Nail,1,0.0,0.0,1.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Nail,2,0.0,0.0,1.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Nail,3,0.0,0.0,1.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Nail,4,0.0,0.0,1.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,Nail,5,0.0,0.0,1.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,UsedBoat,5,0.0,0.0,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,UsedBoat,1,6.31579,0.0,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,UsedBoat,2,22.93629,0.0,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,UsedBoat,3,31.7714,0.0,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,UsedBoat,4,33.80867,0.0,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,UsedBoat,5,34.54174,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,UsedBoat,1,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,UsedBoat,2,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,UsedBoat,3,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,UsedBoat,4,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,UsedBoat,5,0.0,0.0,0.0,0.0
--- a/test/fixtures/boat_example/plant_outputs.csv
+++ b/test/fixtures/boat_example/plant_outputs.csv
@ -20,7 +20,7 @@ BoatFactory (Houston),29.760427,-95.369804,NewBoat,3,0.0,0.0,0.0,0.0
 BoatFactory (Houston),29.760427,-95.369804,NewBoat,4,0.0,0.0,0.0,0.0
 BoatFactory (Houston),29.760427,-95.369804,NewBoat,5,0.0,0.0,0.0,0.0
 BoatFactory (Phoenix),33.448376,-112.074036,NewBoat,1,0.0,0.0,0.0,0.0
-BoatFactory (Phoenix),33.448376,-112.074036,NewBoat,2,-0.0,0.0,0.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,NewBoat,2,0.0,0.0,0.0,0.0
 BoatFactory (Phoenix),33.448376,-112.074036,NewBoat,3,0.0,0.0,0.0,0.0
 BoatFactory (Phoenix),33.448376,-112.074036,NewBoat,4,0.0,0.0,0.0,0.0
 BoatFactory (Phoenix),33.448376,-112.074036,NewBoat,5,0.0,0.0,0.0,0.0
@ -60,15 +60,15 @@ RecyclingPlant (Chicago),41.881832,-87.623177,Wood,3,0.0,0.0,0.0,0.0
 RecyclingPlant (Chicago),41.881832,-87.623177,Wood,4,0.0,0.0,0.0,0.0
 RecyclingPlant (Chicago),41.881832,-87.623177,Wood,5,0.0,0.0,0.0,0.0
 RecyclingPlant (New York City),40.712776,-74.005974,Nail,1,0.0,0.0,0.0,0.0
-RecyclingPlant (New York City),40.712776,-74.005974,Nail,2,-0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,Nail,2,0.0,0.0,0.0,0.0
 RecyclingPlant (New York City),40.712776,-74.005974,Nail,3,0.0,0.0,0.0,0.0
-RecyclingPlant (New York City),40.712776,-74.005974,Nail,4,-0.0,0.0,0.0,0.0
-RecyclingPlant (New York City),40.712776,-74.005974,Nail,5,-0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,Nail,4,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,Nail,5,0.0,0.0,0.0,0.0
 RecyclingPlant (New York City),40.712776,-74.005974,Wood,1,0.0,0.0,0.0,0.0
-RecyclingPlant (New York City),40.712776,-74.005974,Wood,2,-0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,Wood,2,0.0,0.0,0.0,0.0
 RecyclingPlant (New York City),40.712776,-74.005974,Wood,3,0.0,0.0,0.0,0.0
-RecyclingPlant (New York City),40.712776,-74.005974,Wood,4,-0.0,0.0,0.0,0.0
-RecyclingPlant (New York City),40.712776,-74.005974,Wood,5,-0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,Wood,4,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,Wood,5,0.0,0.0,0.0,0.0
 RecyclingPlant (Los Angeles),34.052235,-118.243683,Nail,1,0.0,0.0,0.0,0.0
 RecyclingPlant (Los Angeles),34.052235,-118.243683,Nail,2,0.0,0.0,0.0,0.0
 RecyclingPlant (Los Angeles),34.052235,-118.243683,Nail,3,0.0,0.0,0.0,0.0
@ -90,14 +90,14 @@ RecyclingPlant (Houston),29.760427,-95.369804,Wood,3,0.0,0.0,0.0,0.0
 RecyclingPlant (Houston),29.760427,-95.369804,Wood,4,0.0,0.0,0.0,0.0
 RecyclingPlant (Houston),29.760427,-95.369804,Wood,5,0.0,0.0,0.0,0.0
 RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,1,0.0,0.0,0.0,0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,2,-0.0,0.0,0.0,0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,3,-0.0,0.0,0.0,0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,4,-0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,4,0.0,0.0,0.0,0.0
 RecyclingPlant (Phoenix),33.448376,-112.074036,Nail,5,0.0,0.0,0.0,0.0
 RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,1,0.0,0.0,0.0,0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,2,-0.0,0.0,0.0,0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,3,-0.0,0.0,0.0,0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,4,-0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,2,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,3,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,4,0.0,0.0,0.0,0.0
 RecyclingPlant (Phoenix),33.448376,-112.074036,Wood,5,0.0,0.0,0.0,0.0
 RecyclingPlant (Philadelphia),39.952583,-75.165222,Nail,1,0.0,0.0,0.0,0.0
 RecyclingPlant (Philadelphia),39.952583,-75.165222,Nail,2,0.0,0.0,0.0,0.0
@ -109,12 +109,12 @@ RecyclingPlant (Philadelphia),39.952583,-75.165222,Wood,2,0.0,0.0,0.0,0.0
 RecyclingPlant (Philadelphia),39.952583,-75.165222,Wood,3,0.0,0.0,0.0,0.0
 RecyclingPlant (Philadelphia),39.952583,-75.165222,Wood,4,0.0,0.0,0.0,0.0
 RecyclingPlant (Philadelphia),39.952583,-75.165222,Wood,5,0.0,0.0,0.0,0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,Nail,1,-0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,Nail,1,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Nail,2,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Nail,3,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Nail,4,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Nail,5,0.0,0.0,0.0,0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,Wood,1,-0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,Wood,1,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Wood,2,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Wood,3,0.0,0.0,0.0,0.0
 RecyclingPlant (San Antonio),29.424122,-98.493629,Wood,4,0.0,0.0,0.0,0.0
--- a/test/fixtures/boat_example/plants.csv
+++ b/test/fixtures/boat_example/plants.csv
@ -1,101 +1,101 @@
-plant,latitude,longitude,initial capacity,current capacity,year,operational?,input amount (tonne),opening cost ($),fixed operating cost ($),variable operating cost ($)
-BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,3,false,0.0,0.0,0.0,0.0
-BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,3,false,0.0,0.0,0.0,0.0
-BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,5,false,0.0,0.0,0.0,0.0
-BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,3,false,0.0,0.0,0.0,0.0
-BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,1,true,63.15789,100000.0,250000.0,315.78947
-BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,2,true,71.46814,0.0,250000.0,357.34072
-BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,3,true,75.8857,0.0,250000.0,379.42849
-BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,4,true,76.90434,0.0,250000.0,384.52168
-BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,5,true,77.27087,0.0,250000.0,386.35435
-BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,2,false,0.0,0.0,0.0,0.0
-RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,3,false,0.0,0.0,0.0,0.0
-RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,4,false,0.0,0.0,0.0,0.0
-RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,2,false,0.0,0.0,0.0,0.0
-RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,4,false,0.0,0.0,0.0,0.0
-RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,5,false,0.0,0.0,0.0,0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,2,false,0.0,0.0,0.0,0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,3,false,0.0,0.0,0.0,0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,4,false,0.0,0.0,0.0,0.0
-RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,5,false,0.0,0.0,0.0,0.0
-RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,1,true,6.31579,500000.0,125000.0,15.78947
-RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,2,true,22.93629,0.0,125000.0,57.34072
-RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,3,true,31.7714,0.0,125000.0,79.42849
-RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,4,true,33.80867,0.0,125000.0,84.52168
-RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,5,true,34.54174,0.0,125000.0,86.35435
-RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,1,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,2,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,3,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,4,false,-0.0,0.0,0.0,-0.0
-RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,5,false,-0.0,0.0,0.0,-0.0
+plant,latitude,longitude,initial capacity,current capacity,year,operational?,input amount (tonne),stored amount (tonne),processed amount (tonne),opening cost ($),fixed operating cost ($),variable operating cost ($),expansion cost ($),storage cost ($)
+BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Chicago),41.881832,-87.623177,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (New York City),40.712776,-74.005974,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Los Angeles),34.052235,-118.243683,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Houston),29.760427,-95.369804,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Phoenix),33.448376,-112.074036,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Philadelphia),39.952583,-75.165222,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Antonio),29.424122,-98.493629,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Diego),32.715736,-117.161087,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,1,true,63.15789,0.0,63.15789,100000.0,250000.0,315.78947,0.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,2,true,71.46814,0.0,71.46814,0.0,250000.0,357.34072,0.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,3,true,75.8857,0.0,75.8857,0.0,250000.0,379.42849,0.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,4,true,76.90434,0.0,76.90434,0.0,250000.0,384.52168,0.0,0.0
+BoatFactory (Dallas),32.776664,-96.796988,0.0,500.0,5,true,77.27087,0.0,77.27087,0.0,250000.0,386.35435,0.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+BoatFactory (San Jose),37.338208,-121.886329,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Chicago),41.881832,-87.623177,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (New York City),40.712776,-74.005974,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Los Angeles),34.052235,-118.243683,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Houston),29.760427,-95.369804,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Phoenix),33.448376,-112.074036,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Philadelphia),39.952583,-75.165222,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Antonio),29.424122,-98.493629,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Diego),32.715736,-117.161087,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,1,true,6.31579,0.0,6.31579,500000.0,125000.0,15.78947,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,2,true,22.93629,0.0,22.93629,0.0,125000.0,57.34072,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,3,true,31.7714,0.0,31.7714,0.0,125000.0,79.42849,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,4,true,33.80867,0.0,33.80867,0.0,125000.0,84.52168,0.0,0.0
+RecyclingPlant (Dallas),32.776664,-96.796988,0.0,500.0,5,true,34.54174,0.0,34.54174,0.0,125000.0,86.35435,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,1,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,2,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,3,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,4,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
+RecyclingPlant (San Jose),37.338208,-121.886329,0.0,0.0,5,false,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0
--- a/test/fixtures/simple.json
+++ b/test/fixtures/simple.json
@ -153,7 +153,7 @@
          "variable operating cost ($/tonne)": 5.0
        }
      ],
-      "initial capacity (tonne)": 0
+      "initial capacity (tonne)": 250
    }
  },
  "emissions": {
--- a/test/src/instance/parse_test.jl
+++ b/test/src/instance/parse_test.jl
@ -56,7 +56,7 @@ function instance_parse_test_1()
    @test l1.disposal_cost == Dict(p3 => [0, 0, 0, 0], p4 => [0.86, 0.86, 0.86, 0.86])
    @test l1.disposal_limit ==
          Dict(p3 => [Inf, Inf, Inf, Inf], p4 => [1000.0, 1000.0, 1000.0, 1000.0])
-    @test l1.initial_capacity == 0
+    @test l1.initial_capacity == 250
    @test length(l1.capacities) == 2
    c1 = l1.capacities[1]
    @test c1.size == 100
--- a/test/src/model/build_test.jl
+++ b/test/src/model/build_test.jl
@ -9,8 +9,11 @@ function model_build_test()
    y = model[:y]
    z_disp = model[:z_disp]
    z_input = model[:z_input]
+    z_process = model[:z_process]
+    z_storage = model[:z_storage]
    z_em_tr = model[:z_em_tr]
    z_em_plant = model[:z_em_plant]
+    z_exp = model[:z_exp]
    x = model[:x]
    obj = objective_function(model)
    # print(model)
@ -27,6 +30,8 @@ function model_build_test()
    @test obj.terms[z_disp["C1", "P2", 1]] == 0.23
    @test obj.constant == (
        150 * 4 * 3 # center operating cost
+        - 300 # initial opening cost
+        - 150 * 1.75 # initial expansion
    )
    @test obj.terms[z_disp["L1", "P4", 2]] == 0.86
    @test obj.terms[x["L1", 1]] == (
@ -46,6 +51,27 @@ function model_build_test()
        300 # fixed operating cost
    )

+    # Test expansion variables exist and have correct initial values
+    @test z_exp["L1", 0] == 150.0  # initial_capacity (250) - min_capacity (100)
+    @test haskey(z_exp, ("L1", 1))
+    @test haskey(z_exp, ("L1", 2))
+    @test haskey(z_exp, ("L1", 3))
+    @test haskey(z_exp, ("L1", 4))
+
+    # Test expansion costs in objective function
+    # R_expand[1] = (1000 - 300) / (500 - 100) = 1.75
+    # R_expand[2] = (1000 - 400) / (500 - 100) = 1.5
+    # R_fix_exp[1] = (400 - 300) / (500 - 100) = 0.25
+    @test obj.terms[z_exp["L1", 1]] == (
+        +1.75  # expansion cost[1]
+        - 1.5  # expansion cost[2]
+        + 0.25   # fixed operating cost[1]
+    )
+
+    # Test storage cost in objective function
+    @test obj.terms[z_storage["L1", "P1", 1]] == 0.1  # P1 storage cost
+    @test obj.terms[z_storage["L1", "P2", 1]] == 0.1  # P2 storage cost
+
    # Variables: Transportation emissions
    @test haskey(z_em_tr, ("CO2", "L1", "C3", "P4", 1))
    @test haskey(z_em_tr, ("CH4", "L1", "C3", "P4", 1))
@ -62,17 +88,21 @@ function model_build_test()
    @test repr(model[:eq_z_input]["L1", 1]) ==
          "eq_z_input[L1,1] : -y[C2,L1,P1,1] - y[C1,L1,P2,1] + z_input[L1,1] = 0"

-    # Plants: Must meet input mix
-    @test repr(model[:eq_input_mix]["L1", "P1", 1]) ==
-          "eq_input_mix[L1,P1,1] : y[C2,L1,P1,1] - 0.953 z_input[L1,1] = 0"
-    @test repr(model[:eq_input_mix]["L1", "P2", 1]) ==
-          "eq_input_mix[L1,P2,1] : y[C1,L1,P2,1] - 0.047 z_input[L1,1] = 0"
+    # Plants: Definition of total processing amount
+    @test repr(model[:eq_z_process]["L1", 1]) ==
+          "eq_z_process[L1,1] : -z_input[L1,1] + z_storage[L1,P1,1] + z_storage[L1,P2,1] + z_process[L1,1] = 0"
+
+    # Plants: Processing mix must have correct proportion
+    @test repr(model[:eq_process_mix]["L1", "P1", 1]) ==
+          "eq_process_mix[L1,P1,1] : y[C2,L1,P1,1] - z_storage[L1,P1,1] - 0.953 z_process[L1,1] = 0"
+    @test repr(model[:eq_process_mix]["L1", "P2", 1]) ==
+          "eq_process_mix[L1,P2,1] : y[C1,L1,P2,1] - z_storage[L1,P2,1] - 0.047 z_process[L1,1] = 0"

    # Plants: Calculate amount produced
    @test repr(model[:eq_z_prod]["L1", "P3", 1]) ==
-          "eq_z_prod[L1,P3,1] : z_prod[L1,P3,1] - 0.25 z_input[L1,1] = 0"
+          "eq_z_prod[L1,P3,1] : z_prod[L1,P3,1] - 0.25 z_process[L1,1] = 0"
    @test repr(model[:eq_z_prod]["L1", "P4", 1]) ==
-          "eq_z_prod[L1,P4,1] : z_prod[L1,P4,1] - 0.12 z_input[L1,1] = 0"
+          "eq_z_prod[L1,P4,1] : z_prod[L1,P4,1] - 0.12 z_process[L1,1] = 0"

    # Plants: Produced material must be sent or disposed
    @test repr(model[:eq_balance]["L1", "P3", 1]) ==
@ -80,9 +110,13 @@ function model_build_test()
    @test repr(model[:eq_balance]["L1", "P4", 1]) ==
          "eq_balance[L1,P4,1] : -y[L1,C3,P4,1] + z_prod[L1,P4,1] - z_disp[L1,P4,1] = 0"

-    # Plants: Capacity limit
-    @test repr(model[:eq_capacity]["L1", 1]) ==
-          "eq_capacity[L1,1] : -100 x[L1,1] + z_input[L1,1] ≤ 0"
+    # Plants: Processing limit (capacity constraint)
+    @test repr(model[:eq_process_limit]["L1", 1]) ==
+          "eq_process_limit[L1,1] : -100 x[L1,1] - z_exp[L1,1] + z_process[L1,1] ≤ 0"
+
+    # Plants: Expansion upper bound
+    @test repr(model[:eq_exp_ub]["L1", 1]) ==
+          "eq_exp_ub[L1,1] : -400 x[L1,1] + z_exp[L1,1] ≤ 0"

    # Plants: Disposal limit
    @test repr(model[:eq_disposal_limit]["L1", "P4", 1]) ==
@ -92,7 +126,7 @@ function model_build_test()
    # Plants: Plant remains open
    @test repr(model[:eq_keep_open]["L1", 4]) ==
          "eq_keep_open[L1,4] : -x[L1,3] + x[L1,4] ≥ 0"
-    @test repr(model[:eq_keep_open]["L1", 1]) == "eq_keep_open[L1,1] : x[L1,1] ≥ 0"
+    @test repr(model[:eq_keep_open]["L1", 1]) == "eq_keep_open[L1,1] : x[L1,1] ≥ 1"

    # Plants: Building period
    @test ("L1", 1) ∉ keys(model[:eq_building_period])
@ -137,9 +171,9 @@ function model_build_test()
    @test repr(model[:eq_emission_tr]["CH4", "L1", "C3", "P4", 1]) ==
          "eq_emission_tr[CH4,L1,C3,P4,1] : -0.333354 y[L1,C3,P4,1] + z_em_tr[CH4,L1,C3,P4,1] = 0"

-    # Plants: Plant emissions
+    # Plants: Plant emissions (updated to use z_process)
    @test repr(model[:eq_emission_plant]["CO2", "L1", 1]) ==
-          "eq_emission_plant[CO2,L1,1] : -0.1 y[C2,L1,P1,1] - 0.1 y[C1,L1,P2,1] + z_em_plant[CO2,L1,1] = 0"
+          "eq_emission_plant[CO2,L1,1] : -0.1 z_process[L1,1] + z_em_plant[CO2,L1,1] = 0"

    # Objective function: Emissions penalty costs
    @test obj.terms[z_em_plant["CO2", "L1", 1]] == 50.0  # CO2 penalty at time 1
@ -153,4 +187,30 @@ function model_build_test()
    @test repr(model[:eq_emission_limit]["CO2", 1]) ==
          "eq_emission_limit[CO2,1] : z_em_tr[CO2,C2,L1,P1,1] + z_em_tr[CO2,C2,C1,P1,1] + z_em_tr[CO2,C1,L1,P2,1] + z_em_tr[CO2,L1,C3,P4,1] + z_em_plant[CO2,L1,1] ≤ 1000"
    @test ("CH4", 1) ∉ keys(model[:eq_emission_limit])
+
+    # Test storage variables exist
+    @test haskey(z_storage, ("L1", "P1", 1))
+    @test haskey(z_storage, ("L1", "P2", 1))
+    @test haskey(z_process, ("L1", 1))
+    @test haskey(z_process, ("L1", 2))
+    @test haskey(z_process, ("L1", 3))
+    @test haskey(z_process, ("L1", 4))
+
+    # Test initial storage values
+    @test z_storage["L1", "P1", 0] == 0
+    @test z_storage["L1", "P2", 0] == 0
+
+    # Test storage limit constraints (P1 has limit of 100, P2 has no limit)
+    @test haskey(model[:eq_storage_limit], ("L1", "P1", 1))
+    @test repr(model[:eq_storage_limit]["L1", "P1", 1]) ==
+          "eq_storage_limit[L1,P1,1] : z_storage[L1,P1,1] ≤ 100"
+    @test ("L1", "P2", 1) ∉ keys(model[:eq_storage_limit])  # P2 has no storage limit
+
+    # Test final storage constraints exist
+    @test haskey(model[:eq_storage_final], ("L1", "P1"))
+    @test haskey(model[:eq_storage_final], ("L1", "P2"))
+    @test repr(model[:eq_storage_final]["L1", "P1"]) ==
+          "eq_storage_final[L1,P1] : z_storage[L1,P1,4] = 0"
+    @test repr(model[:eq_storage_final]["L1", "P2"]) ==
+          "eq_storage_final[L1,P2] : z_storage[L1,P2,4] = 0"
 end
--- a/test/src/reports_test.jl
+++ b/test/src/reports_test.jl
@ -6,6 +6,7 @@ function report_tests()
    mkpath("tmp")
    write_to_file(model, "tmp/model.lp")
    RELOG.write_plants_report(model, "tmp/plants.csv")
+    RELOG.write_plant_inputs_report(model, "tmp/plant_inputs.csv")
    RELOG.write_plant_outputs_report(model, "tmp/plant_outputs.csv")
    RELOG.write_centers_report(model, "tmp/centers.csv")
    RELOG.write_center_outputs_report(model, "tmp/center_outputs.csv")
Author	SHA1	Message	Date
Alinson S. Xavier	5eee29547c	Reformat source code	1 week ago
Alinson S. Xavier	897717677f	Implement plant storage	1 week ago
Alinson S. Xavier	480547933b	Implement plant expansion	1 week ago