Thermal Steam

Overview

Thermal Steam assets in MacroEnergy.jl represent combined steam and power or co-generation systems that convert a primary fuel (such as natural gas) into steam and electricity simultaneously. These assets are typically used in industrial plants or district energy systems where waste steam recovery is desirable.

They are defined using JSON or CSV input files placed in the assets directory, usually named with descriptive identifiers such as gas_cogen.json, fuel_steam.json, or gas_steam.json.

Asset Structure

A thermal steam asset consists of five main components:

Transformation Component: Balances the energy conversion process among fuel, steam, electricity, and CO₂ flows
Fuel Edge: Represents the primary fuel input to the co-generation unit
Steam Edge: Represents the production of process steam (may include unit commitment operations)
Electricity Edge: Represents the co-generated electricity output
CO₂ Edge: Represents the emissions produced by the combustion process

Below is a schematic representation of the thermal steam asset:

%%{init: {'theme': 'base', 'themeVariables': { 'background': '#D1EBDE' }}}%% flowchart LR subgraph ThermalSteam direction BT A((Fuel)) e1@ --> B{{..}} B e2@ --> C((Steam)) B e3@ --> D((Electricity)) B e4@ --> E((CO₂ Emitted)) e1@{animate: true} e2@{animate: true} e3@{animate: true} e4@{animate: true} end style A r:55px,fill:#005F6A,stroke:black,color:white,stroke-dasharray: 3,5; style B r:55px,fill:black,stroke:black,color:black,stroke-dasharray: 3,5; style C font-size:26px,r:55px,fill:#FFA500,stroke:black,color:black,stroke-dasharray: 3,5; style D font-size:19px,r:55px,fill:#8EC7FF,stroke:black,color:black,stroke-dasharray: 3,5; style E font-size:17px,r:55px,fill:lightgray,stroke:black,color:black,stroke-dasharray: 3,5; linkStyle 0 stroke:#005F6A, stroke-width: 2px; linkStyle 1 stroke:#FFA500, stroke-width: 2px; linkStyle 2 stroke:#8EC7FF, stroke-width: 2px; linkStyle 3 stroke:lightgray, stroke-width: 2px;

Flow Equations

The thermal steam asset follows the following stoichiometric and co-generation relationships:

\[\begin{aligned} \phi_{fuel} &= \phi_{steam} \cdot \epsilon_{fuel\_consumption} \\ \phi_{elec} &= \phi_{fuel} \cdot \epsilon_{elec\_cogen\_rate} \\ \phi_{co2} &= \phi_{fuel} \cdot \epsilon_{emission\_rate} \\ \end{aligned}\]

Where:

$\phi$ represents the flow of each commodity
$\epsilon$ represents the stoichiometric coefficients defined in the Conversion Process Parameters section.

Input File (Standard Format)

Techno-Economic Analysis

Techno-economic analysis background is recommended for updating or adding conversion process parameters. For users not familiar with TEA, they can refer to this guide.

The easiest way to include a thermal steam 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/
│   ├── fuel_steam.json    # or fuel_steam.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.

The following is an example of a natural gas co-generation (thermal steam) asset input file:

{
    "NaturalGasSteam": [
        {
            "type": "ThermalSteam",
            "instance_data": [
                {
                    "id": "SE_natgas_cogen_steam_1",
                    "location": "SE",
                    "fuel_commodity": "NaturalGas",
                    "co2_sink": "co2_sink",
                    "capacity_size": 80,
                    "fuel_consumption": 1.20,
                    "emission_rate": 0.18,
                    "elec_cogen_rate": 0.15,
                    "investment_cost": 30000,
                    "fixed_om_cost": 2500,
                    "variable_om_cost": 3.5,
                    "uc": false,
                    "ramp_up_fraction": 0.8,
                    "ramp_down_fraction": 0.8
                }
            ]
        }
    ]
}

Global Data vs Instance Data

When working with JSON input files, the global_data field can be used to group data that is common to all instances of the same asset type. This is useful for setting constraints that are common to all instances of the same asset type and avoid repeating the same data for each instance. See the Examples section below for an example.

The following tables outline the attributes that can be set for a thermal steam (co-generation) asset.

Essential Attributes

Field	Type	Description
`Type`	String	Asset type identifier: `"ThermalSteam"`
`id`	String	Unique identifier for the co-generation unit instance
`location`	String	Geographic location or node identifier
`fuel_commodity`	String	Primary fuel commodity identifier
`uc`	Boolean	Whether unit commitment is enabled (default: false)
`timedata`	String	Time resolution for time series data (default: `"Steam"`)
`co2_sink`	String	CO₂ sink identifier
`fuel_start_vertex`	String	Fuel start vertex identifier. This is not required if the fuel commodity is present in the location.

Conversion Process Parameters

The following parameters control the conversion process and stoichiometric relationships of the thermal steam asset (see Flow Equations for more details).

Field	Type	Description	Units	Default
`fuel_consumption`	Float64	Fuel consumption rate per unit of steam output	$MWh_{fuel}/MWh_{steam}$	1.0
`elec_cogen_rate`	Float64	Electricity co-generation rate per unit of fuel input	$MWh_{elec}/MWh_{fuel}$	0.0
`emission_rate`	Float64	CO₂ emission rate per unit of fuel input	$t_{CO₂}/MWh_{fuel}$	0.0

Constraints Configuration

Thermal Steam assets can have different constraints applied to their transformation and edges. Users can configure these using the following fields:

Field	Type	Description
`transform_constraints`	Dict{String,Bool}	List of constraints applied to the transformation component.
`steam_constraints`	Dict{String,Bool}	List of constraints applied to the steam edge.
`elec_constraints`	Dict{String,Bool}	List of constraints applied to the electricity edge.
`fuel_constraints`	Dict{String,Bool}	List of constraints applied to the fuel edge.
`co2_constraints`	Dict{String,Bool}	List of constraints applied to the CO₂ edge.

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

{
    "transform_constraints": {
        "BalanceConstraint": true
    },
    "steam_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 a thermal steam asset.

Default constraints

To simplify the input file and configuration, the following constraints are applied to the thermal steam (co-generation) asset by default:

Balance constraint — applied to the transformation component
Capacity constraint — applied to the steam edge
Ramping limits constraint — applied to the steam edge

Unit commitment constraints (when uc is set to true):

Minimum up and down time constraint — applied to the steam edge

Investment Parameters

Field	Type	Description	Units	Default
`can_retire`	Boolean	Whether the steam generation capacity can be retired	-	true
`can_expand`	Boolean	Whether the steam generation capacity can be expanded	-	true
`existing_capacity`	Float64	Installed capacity of the steam edge	MW	0.0
`capacity_size`	Float64	Unit size for capacity decision variables	-	1.0

Additional Investment Parameters

Maximum and minimum capacity constraints

If MaxCapacityConstraint or MinCapacityConstraint are added to the constraints dictionary for the steam edge, the following parameters are used by Macro:

Field	Type	Description	Units	Default
`max_capacity`	Float64	Maximum allowed steam capacity	MW	Inf
`min_capacity`	Float64	Minimum allowed steam capacity	MW	0.0

Economic Parameters

Field	Type	Description	Units	Default
`investment_cost`	Float64	CAPEX per unit of installed steam capacity	$/MW	0.0
`annualized_investment_cost`	Union{Nothing,Float64}	Annualized CAPEX for steam capacity	$/MW/yr	calculated
`fixed_om_cost`	Float64	Fixed O&M costs for steam generation	$/MW/yr	0.0
`variable_om_cost`	Float64	Variable O&M costs per unit of steam produced	$/MWh	0.0
`startup_cost`	Float64	Cost per MW of capacity to start the co-generation unit	$/MW per start	0.0
`wacc`	Float64	Weighted average cost of capital	fraction	0.0
`lifetime`	Int	Asset lifetime in years	years	1
`capital_recovery_period`	Int	Investment recovery period	years	1
`retirement_period`	Int	Retirement period	years	0

Operational Parameters

Field	Type	Description	Units	Default
`availability`	Dict	Availability file path and header	-	Empty

Additional Operational Parameters

Unit commitment parameters (when uc is set to true)

Field	Type	Description	Units	Default
`startup_fuel_consumption`	Float64	Fuel consumption per unit steam output to start the co-generation unit	$MWh_{fuel}/MWh_{steam}$	0.0

Minimum flow constraint

If MinFlowConstraint is added to the constraints dictionary for the steam edge, the following parameter is used:

Field	Type	Description	Units	Default
`min_flow_fraction`	Float64	Minimum steam flow as a fraction of installed capacity	fraction	0.0

Ramping limit constraint

If RampingLimitConstraint is added to the constraints dictionary for the steam edge, the following parameters are used:

Field	Type	Description	Units	Default
`ramp_up_fraction`	Float64	Maximum increase in steam flow between timesteps	fraction	1.0
`ramp_down_fraction`	Float64	Maximum decrease in steam flow between timesteps	fraction	1.0

Minimum up and down time constraints

If MinUpTimeConstraint or MinDownTimeConstraint are added to the constraints dictionary for the steam edge, the following parameters are used:

Field	Type	Description	Units	Default
`min_up_time`	Int64	Minimum time the co-generation unit must remain operational once started	hours	0
`min_down_time`	Int64	Minimum time the co-generation unit must remain offline once shut down	hours	0

Types - Asset Structure

The ThermalSteam asset is defined as follows:

struct ThermalSteam{T} <: AbstractAsset
    id::AssetId
    steam_transform::Transformation
    steam_edge::Union{Edge{<:Steam},EdgeWithUC{<:Steam}}
    fuel_edge::Edge{<:T}
    elec_edge::Edge{<:Electricity}
    co2_edge::Edge{<:CO2}
end

Constructors

Default constructor

ThermalSteam(
    id::AssetId,
    steam_transform::Transformation,
    steam_edge::Union{Edge{<:Steam},EdgeWithUC{<:Steam}},
    fuel_edge::Edge{<:Fuel},
    elec_edge::Edge{<:Electricity},
    co2_edge::Edge{<:CO2}
)

Factory constructor

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

Field	Type	Description
`asset_type`	`Type{Thermalsteam}`	Macro type of the asset
`data`	`AbstractDict{Symbol,Any}`	Dictionary containing the input data for the asset
`system`	`System`	System to which the asset belongs

Examples

This section contains examples of how to use the thermal steam (co-generation) asset in a Macro model.

Natural Gas Steam Boiler with Electricity Co-generation

This example shows a natural-gas-fired boiler that produces both steam and electricity. The asset has an existing capacity that is only allowed to be retired. A MinFlowConstraint constraint is applied to the steam edge with a minimum flow fraction of 0.5. The asset co-generates electricity according to the elec_cogen_rate parameter and includes unit-commitment operation with startup cost, startup fuel consumption, and ramping limits.

JSON Format:

{
    "GasSteamBoiler": [
        {
            "type": "ThermalSteam",
            "instance_data": [
                {
                    "id": "SE_natgas_steam_cogen_1",
                    "location": "SE",
                    "timedata": "Steam",
                    "fuel_commodity": "NaturalGas",
                    "fuel_start_vertex": "natgas_source",
                    "co2_sink": "co2_sink",
                    "uc": true,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 800.0,
                    "capacity_size": 100.0,
                    "steam_constraints": {
                        "MinFlowConstraint": true,
                        "MinUpTimeConstraint": true,
                        "MinDownTimeConstraint": true,
                        "RampingLimitConstraint": true
                    },
                    "fuel_consumption": 1.3,
                    "emission_rate": 0.18,
                    "elec_cogen_rate": 0.25,
                    "fixed_om_cost": 7000,
                    "variable_om_cost": 5.5,
                    "startup_cost": 60.0,
                    "startup_fuel_consumption": 0.25,
                    "min_up_time": 6,
                    "min_down_time": 6,
                    "ramp_up_fraction": 0.7,
                    "ramp_down_fraction": 0.7,
                    "min_flow_fraction": 0.5
                }
            ]
        }
    ]
}

CSV Format:

Type	id	location	time_data	fuel_commodity	fuel_start_vertex	co2_sink	uc	can_retire	can_expand	existing_capacity	capacity_size	steam_constraints–MinFlowConstraint	steam_constraints–MinUpTimeConstraint	steam_constraints–MinDownTimeConstraint	steam_constraints–RampingLimitConstraint	fuel_consumption	emission_rate	elec_cogen_rate	fixed_om_cost	variable_om_cost	startup_cost	startup_fuel_consumption	min_up_time	min_down_time	ramp_up_fraction	ramp_down_fraction	min_flow_fraction
ThermalSteam	SE_natgas_steam_cogen_1	SE	Steam	NaturalGas	natgas_source	co2_sink	true	true	false	800.0	100.0	true	true	true	true	1.3	0.18	0.25	7000	5.5	60.0	0.25	6	6	0.7	0.7	0.5

Multiple Natural Gas Steam Cogeneration Units in Different Zones

This example shows three natural gas–fired cogeneration (steam) units using natural gas as fuel. Each asset produces both steam and electricity (via the elec_cogen_rate parameter). All units have existing capacity that is only allowed to be retired. A MinFlowConstraint constraint is applied to the steam edge with a minimum flow fraction of 0.444, 0.526, and 0.41. A MinUpTimeConstraint and MinDownTimeConstraint constraint is applied to the steam edge with a minimum up and down time of 6 hours. A RampingLimitConstraint constraint is applied to the steam edge with a ramping limit of 0.64.

JSON Format:

{
    "NaturalGasSteam": [
        {
            "type": "ThermalSteam",
            "global_data": {
                "timedata": "Steam",
                "fuel_commodity": "NaturalGas",
                "co2_sink": "co2_sink",
                "uc": true,
                "steam_constraints": {
                    "MinFlowConstraint": true,
                    "MinUpTimeConstraint": true,
                    "MinDownTimeConstraint": true
                }
            },
            "instance_data": [
                {
                    "id": "MIDAT_natgas_steam_cogen_1",
                    "location": "MIDAT",
                    "emission_rate": 0.181048235160161,
                    "fuel_consumption": 1.9,
                    "elec_cogen_rate": 0.25,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 4000.0,
                    "investment_cost": 0.0,
                    "fixed_om_cost": 8500,
                    "variable_om_cost": 4.8,
                    "capacity_size": 100.0,
                    "startup_cost": 50.0,
                    "startup_fuel_consumption": 0.2,
                    "min_up_time": 6,
                    "min_down_time": 6,
                    "ramp_up_fraction": 0.64,
                    "ramp_down_fraction": 0.64,
                    "min_flow_fraction": 0.444
                },
                {
                    "id": "NE_natgas_steam_cogen_1",
                    "location": "NE",
                    "emission_rate": 0.181048235160161,
                    "fuel_consumption": 2.0,
                    "elec_cogen_rate": 0.22,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 6000.0,
                    "investment_cost": 0.0,
                    "fixed_om_cost": 8700,
                    "variable_om_cost": 4.9,
                    "capacity_size": 120.0,
                    "startup_cost": 50.0,
                    "startup_fuel_consumption": 0.2,
                    "min_up_time": 6,
                    "min_down_time": 6,
                    "ramp_up_fraction": 0.64,
                    "ramp_down_fraction": 0.64,
                    "min_flow_fraction": 0.526
                },
                {
                    "id": "SE_natgas_steam_cogen_1",
                    "location": "SE",
                    "emission_rate": 0.181048235160161,
                    "fuel_consumption": 1.8,
                    "elec_cogen_rate": 0.27,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 25000.0,
                    "investment_cost": 0.0,
                    "fixed_om_cost": 7800,
                    "variable_om_cost": 4.1,
                    "capacity_size": 500.0,
                    "startup_cost": 50.0,
                    "startup_fuel_consumption": 0.2,
                    "min_up_time": 6,
                    "min_down_time": 6,
                    "ramp_up_fraction": 0.64,
                    "ramp_down_fraction": 0.64,
                    "min_flow_fraction": 0.41
                }
            ]
        }
    ]
}

CSV Format:

Type	id	location	time_data	fuel_commodity	co2_sink	uc	can_retire	can_expand	existing_capacity	capacity_size	steam_constraints–MinFlowConstraint	steam_constraints–MinUpTimeConstraint	steam_constraints–MinDownTimeConstraint	fuel_consumption	emission_rate	elec_cogen_rate	fixed_om_cost	variable_om_cost	startup_cost	startup_fuel_consumption	min_up_time	min_down_time	ramp_up_fraction	ramp_down_fraction	min_flow_fraction
ThermalSteam	MIDAT_natgas_steam_cogen_1	MIDAT	Steam	NaturalGas	co2_sink	true	true	false	4000.0	100.0	true	true	true	1.9	0.181	0.25	8500	4.8	50.0	0.2	6	6	0.64	0.64	0.444
ThermalSteam	NE_natgas_steam_cogen_1	NE	Steam	NaturalGas	co2_sink	true	true	false	6000.0	120.0	true	true	true	2.0	0.181	0.22	8700	4.9	50.0	0.2	6	6	0.64	0.64	0.526
ThermalSteam	SE_natgas_steam_cogen_1	SE	Steam	NaturalGas	co2_sink	true	true	false	25000.0	500.0	true	true	true	1.8	0.181	0.27	7800	4.1	50.0	0.2	6	6	0.64	0.64	0.41

Best Practices

Use global data for common parameters: Use the global_data field to set the fields and constraints that are common to all instances of the same asset type.
Set realistic efficiency parameters: Ensure fuel consumption, emission rates, and capture rates are accurate for the technology being modeled
Use meaningful IDs: Choose descriptive identifiers that indicate location and technology type
Consider unit commitment carefully: Enable unit commitment only when detailed operational modeling is needed
Use constraints selectively: Only enable constraints that are necessary for your modeling needs
Validate costs: Ensure investment and O&M costs are in appropriate units and time periods
Test configurations: Start with simple configurations and gradually add complexity
Set appropriate ramp rates: Consider the actual operational characteristics of the technology

Input File (Advanced Format)

Macro provides an advanced format for defining thermal steam assets, offering users and modelers detailed control over asset specifications. This format builds upon the standard format and is ideal for those who need more comprehensive customization.

To understand the advanced format, consider the graph representation and the type definition of a thermal steam asset. The input file mirrors this hierarchical structure.

A thermal steam asset in Macro is composed of a transformation component, represented by a Transformation object, and multiple edges (fuel, steam, CO2), each represented by an Edge object. The input file for a thermal steam asset is therefore organized as follows:

{
    "transforms": {
        // ... transformation-specific attributes ...
    },
    "edges": {
        "fuel_edge": {
            // ... fuel_edge-specific attributes ...
        },
        "steam_edge": {
            // ... steam_edge-specific attributes ...
        },
        "elec_edge": {
            // ... elec_edge-specific attributes ...
        },
        "co2_edge": {
            // ... co2_edge-specific attributes ...
        }
    }
}

Each top-level key (e.g., "transforms" or "edges") denotes a component type. The second-level keys either specify the attributes of the component (when there is a single instance) or identify the instances of the component when there are multiple instances.

Below is an example of an input file for a thermal steam asset that sets up multiple thermal steam plants across different regions:

{
    "NaturalGasSteam": [
        {
            "type": "ThermalSteam",
            "global_data": {
                "transforms": {
                    "timedata": "Steam",
                    "constraints": {
                        "BalanceConstraint": true
                    }
                },
                "edges": {
                    "steam_edge": {
                        "commodity": "Steam",
                        "unidirectional": true,
                        "has_capacity": true,
                        "uc": true,
                        "integer_decisions": false,
                        "constraints": {
                            "CapacityConstraint": true,
                            "RampingLimitConstraint": true,
                            "MinFlowConstraint": true,
                            "MinUpTimeConstraint": true,
                            "MinDownTimeConstraint": true
                        }
                    },
                    "fuel_edge": {
                        "commodity": "NaturalGas",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "elec_edge": {
                        "commodity": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_edge": {
                        "commodity": "CO2",
                        "unidirectional": true,
                        "has_capacity": false,
                        "end_vertex": "co2_sink"
                    }
                }
            },
            "instance_data": [
                {
                    "id": "MIDAT_natgas_steam_cogen_1",
                    "transforms": {
                        "emission_rate": 0.181048235160161,
                        "fuel_consumption": 1.9,
                        "elec_cogen_rate": 0.25
                    },
                    "edges": {
                        "steam_edge": {
                            "end_vertex": "steam_MIDAT",
                            "can_retire": true,
                            "can_expand": false,
                            "existing_capacity": 4000.0,
                            "investment_cost": 0.0,
                            "fixed_om_cost": 8500,
                            "variable_om_cost": 4.8,
                            "capacity_size": 100.0,
                            "startup_cost": 50.0,
                            "startup_fuel_consumption": 0.2,
                            "min_up_time": 6,
                            "min_down_time": 6,
                            "ramp_up_fraction": 0.64,
                            "ramp_down_fraction": 0.64,
                            "min_flow_fraction": 0.444
                        },
                        "fuel_edge": {
                            "start_vertex": "natgas_MIDAT"
                        },
                        "elec_edge": {
                            "end_vertex": "elec_MIDAT"
                        }
                    }
                },
                {
                    "id": "NE_natgas_steam_cogen_1",
                    "transforms": {
                        "emission_rate": 0.181048235160161,
                        "fuel_consumption": 2.0,
                        "elec_cogen_rate": 0.22
                    },
                    "edges": {
                        "steam_edge": {
                            "end_vertex": "steam_NE",
                            "can_retire": true,
                            "can_expand": false,
                            "existing_capacity": 6000.0,
                            "investment_cost": 0.0,
                            "fixed_om_cost": 8700,
                            "variable_om_cost": 4.9,
                            "capacity_size": 120.0,
                            "startup_cost": 50.0,
                            "startup_fuel_consumption": 0.2,
                            "min_up_time": 6,
                            "min_down_time": 6,
                            "ramp_up_fraction": 0.64,
                            "ramp_down_fraction": 0.64,
                            "min_flow_fraction": 0.526
                        },
                        "fuel_edge": {
                            "start_vertex": "natgas_NE"
                        },
                        "elec_edge": {
                            "end_vertex": "elec_NE"
                        }
                    }
                },
                {
                    "id": "SE_natgas_steam_cogen_1",
                    "transforms": {
                        "emission_rate": 0.181048235160161,
                        "fuel_consumption": 1.8,
                        "elec_cogen_rate": 0.27
                    },
                    "edges": {
                        "steam_edge": {
                            "end_vertex": "steam_SE",
                            "can_retire": true,
                            "can_expand": false,
                            "existing_capacity": 25000.0,
                            "investment_cost": 0.0,
                            "fixed_om_cost": 7800,
                            "variable_om_cost": 4.1,
                            "capacity_size": 500.0,
                            "startup_cost": 50.0,
                            "startup_fuel_consumption": 0.2,
                            "min_up_time": 6,
                            "min_down_time": 6,
                            "ramp_up_fraction": 0.64,
                            "ramp_down_fraction": 0.64,
                            "min_flow_fraction": 0.41
                        },
                        "fuel_edge": {
                            "start_vertex": "natgas_SE"
                        },
                        "elec_edge": {
                            "end_vertex": "elec_SE"
                        }
                    }
                }
            ]
        }
    ]
}

Key Points

The global_data field is utilized to define attributes and constraints that apply universally to all instances of a particular asset type.
The start_vertex and end_vertex fields indicate the nodes to which the edges are connected. These nodes must be defined in the nodes.json file.
By default, only the steam edge is allowed to expand as a modeling decision (see note below)
The steam edge can have unit commitment operations enabled by setting the uc attribute to true.
For a comprehensive list of attributes that can be configured for the transformation and edge components, refer to the transformation and edges pages of the Macro manual.

The `has_capacity` Edge Attribute

The has_capacity attribute is a flag that indicates whether a specific edge of an asset has a capacity variable, allowing it to be expanded or retired. Typically, users do not need to manually adjust this flag, as the asset creators in Macro have already configured it correctly for each edge. However, advanced users can use this flag to override the default settings for each edge if needed.

Prefixes

Users can apply prefixes to adjust parameters for the components of a thermal steam asset, even when using the standard format. For instance, co2_can_retire will adjust the can_retire parameter for the CO2 edge, and co2_existing_capacity will adjust the existing_capacity parameter for the CO2 edge. Below are the prefixes available for modifying parameters for the components of a thermal steam asset:

transform_ for the transformation component
steam_ for the steam edge
elec_ for the elec edge
co2_ for the CO2 edge
fuel_ for the fuel edge