Aluminum Smelting

Contents

Overview | Asset Structure | Flow Equations | Input File (Standard Format) | Types - Asset Structure | Constructors | Examples

Overview

In Macro, the Aluminum Smelting asset represents an energy-intensive aluminum production facility using the Hall-Héroult process. This is the primary electrolytic process for producing aluminum from alumina. The process consumes large amounts of electricity (approximately 13.3 MWh per tonne of aluminum), making it one of the most energy-intensive industrial processes. The facility uses alumina and graphite as feedstocks, and produces aluminum and CO₂ emissions.

These assets are defined using either JSON or CSV input files placed in the assets directory, typically named with descriptive identifiers like aluminum_smelting.json or aluminum_smelting.csv.

Asset Structure

An Aluminum Smelting plant is made of the following components:

• 1 Transformation component, representing the aluminum smelting process.
• 5 Edge components:
  • 1 incoming Electricity Edge, representing electricity consumption (approximately 13.3 MWh per tonne of aluminum).
  • 1 incoming Alumina Edge, representing alumina supply (approximately 1.93 tonnes per tonne of aluminum).
  • 1 incoming Graphite Edge, representing graphite supply (approximately 0.45 tonnes per tonne of aluminum).
  • 1 outgoing Aluminum Edge, representing aluminum production.
  • 1 outgoing CO₂ Edge, representing CO₂ emissions from graphite consumption.

Here is a graphical representation of the Aluminum Smelting asset:

Flow Equations

The Aluminum Smelting asset follows these stoichiometric relationships:

\[\begin{aligned} \phi_{elec} &= \phi_{aluminum} \cdot \epsilon_{elec\_aluminum\_rate} \\ \phi_{alumina} &= \phi_{aluminum} \cdot \epsilon_{alumina\_aluminum\_rate} \\ \phi_{graphite} &= \phi_{aluminum} \cdot \epsilon_{graphite\_aluminum\_rate} \\ \phi_{co2} &= \phi_{graphite} \cdot \epsilon_{graphite\_emissions\_rate} \\ \end{aligned}\]

Where:

• $\phi$ represents the flow of each commodity
• $\epsilon$ represents the stoichiometric coefficients defined in the Conversion Process Parameters section.
• Note: Aluminum, Alumina, and Graphite flows are in tonnes, while Electricity is in MWh.

Input File (Standard Format)

The easiest way to include an Aluminum Smelting asset in a model is to create a new file (either JSON or CSV) and place it in the assets directory together with the other assets.

your_case/
├── assets/
│   ├── aluminum_smelting.json    # or aluminum_smelting.csv
│   ├── other_assets.json
│   └── ...
├── system/
├── settings/
└── ...

This file can either be created manually, or using the template_asset function, as shown in the Adding an Asset to a System section of the User Guide. The file will be automatically loaded when you run your Macro model. An example of an input JSON file is shown in the Examples section.

The following tables outline the attributes that can be set for an Aluminum Smelting asset.

Transform Attributes

Essential Attributes

Conversion Process Parameters

General Attributes

Investment Parameters

Economic Parameters

Constraints Configuration

Aluminum Smelting assets can have different constraints applied to them, and the user can configure them using the following fields:

For example, if the user wants to apply the BalanceConstraint to the transformation component and the CapacityConstraint to the output edge, the constraints fields should be set as follows:

{
    "transform_constraints": {
        "BalanceConstraint": true
    },
    "edges":{
        "aluminum_edge": {
            "constraints": {
                "CapacityConstraint": true
            }
        }
    }
}

Users can refer to the Adding Asset Constraints to a System section of the User Guide for a list of all the constraints that can be applied to the different components of an Aluminum Smelting asset.

Default constraints

To simplify the input file and the asset configuration, the following constraints are applied to the Aluminum Smelting asset by default:

• Balance constraint (applied to the transformation component)
• Capacity constraint (applied to the output aluminum edge)

Types - Asset Structure

The Aluminum Smelting asset is defined as follows:

struct AluminumSmelting <: AbstractAsset
    id::AssetId
    aluminumsmelting_transform::Transformation
    elec_edge::Edge{<:Electricity}
    alumina_edge::Edge{<:Alumina}
    graphite_edge::Edge{<:Graphite}
    aluminum_edge::Union{Edge{<:Aluminum},EdgeWithUC{<:Aluminum}}
    co2_edge::Edge{<:CO2}
end

Constructors

Factory constructor

make(asset_type::Type{AluminumSmelting}, data::AbstractDict{Symbol,Any}, system::System)

Stoichiometry balance data

aluminumsmelting_transform.balance_data = Dict(
    :elec_to_aluminum => Dict(
        elec_edge.id => 1.0,
        alumina_edge.id => 0.0,
        graphite_edge.id => 0.0,
        aluminum_edge.id => get(transform_data, :elec_aluminum_rate, 0.0)
        ),
        :alumina_to_aluminum => Dict(
            elec_edge.id => 0.0,
            alumina_edge.id => 1.0,
            graphite_edge.id => 0.0,
            aluminum_edge.id => get(transform_data, :alumina_aluminum_rate, 0.0)
        ),
        :graphite_to_aluminum => Dict(
            elec_edge.id => 0.0,
            alumina_edge.id => 0.0,
            graphite_edge.id => 1.0,
            aluminum_edge.id => get(transform_data, :graphite_aluminum_rate, 0.0)
        ),
        :emissions => Dict(
            graphite_edge.id => get(transform_data, :graphite_emissions_rate, 0.0),
        co2_edge.id => 1.0
    )
)

Examples

This example illustrates a basic Aluminum Smelting configuration in JSON format:

{
    "AluminumSmelting": [
        {
            "type": "AluminumSmelting",
            "global_data":{
                "nodes": {},
                "transforms": {
                    "timedata": "Aluminum"
                },
                "edges":{
                    "aluminum_edge": {
                        "commodity": "Aluminum",
                        "unidirectional": true,
                        "has_capacity": true,
                        "can_retire": true,
                        "can_expand": true,
                        "integer_decisions": false
                    },
                    "elec_edge": {
                        "commodity": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "alumina_edge": {
                        "commodity": "Alumina",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "graphite_edge": {
                        "commodity": "Graphite",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_edge": {
                        "commodity": "CO2",
                        "unidirectional": true,
                        "has_capacity": false,
                        "end_vertex": "co2_sink"
                    }
                }
            },
            "instance_data":[
                {
                    "id": "aluminum_smelting_1",
                    "transforms":{
                        "elec_aluminum_rate": 13.3,
                        "alumina_aluminum_rate": 1.93,
                        "graphite_aluminum_rate": 0.45,
                        "graphite_emissions_rate": 3.67
                    },
                    "edges":{
                        "aluminum_edge": {
                            "end_vertex": "aluminum_node_1",
                            "existing_capacity": 0.0,
                            "investment_cost": 12000000,
                            "fixed_om_cost": 2040000,
                            "variable_om_cost": 62,
                            "startup_cost": 1469798
                        },
                        "elec_edge": {
                            "start_vertex": "elec_node_1"
                        },
                        "alumina_edge": {
                            "start_vertex": "alumina_node_1"
                        },
                        "graphite_edge": {
                            "start_vertex": "graphite_node_1"
                        },
                        "co2_edge": {
                            "end_vertex": "co2_sink"
                        }
                    }
                }
            ]
        }
    ]
}

Related Assets

The following related assets are also available in Macro, though they are typically of secondary importance compared to Aluminum Smelting:

• Aluminum Refining: A facility that transforms electricity and aluminum scrap into refined aluminum. This process is less energy-intensive than smelting (approximately 2.0 MWh per tonne of aluminum).

• Alumina Plant: A facility that produces alumina from bauxite using electricity and fuel. This process has relatively low electricity consumption (approximately 0.15 MWh per tonne of alumina) and is typically not the primary focus in energy system modeling.

See Also

• Edges - Components that connect Vertices and carry flows
• Transformations - Processes that transform flows of several Commodities
• Nodes - Network nodes that allow for import and export of commodities
• Vertices - Network nodes that edges connect
• Assets - Higher-level components made from edges, nodes, storage, and transformations
• Commodities - Types of resources stored by Commodities
• Time Data - Temporal modeling framework
• Constraints - Additional constraints for Storage and other components