Gas Storage

Contents

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

Overview

Gas Storage assets in Macro represent storage systems for gas commodities (such as hydrogen, natural gas, etc.) that can store and release gas using compression technology. These assets are defined using either JSON or CSV input files placed in the assets directory, typically named gas_storage.json or gas_storage.csv.

Asset Structure

A gas storage asset consists of one storage component, one transformation component, and six edge components:

1. Compressor Charge Electricity Edge: Incoming edge representing electricity consumption for compression
2. Compressor Charge Gas Edge: Incoming edge representing gas flow into the compressor
3. Transformation Component: Represents the gas compressor that balances flows
4. Charge Edge: Internal edge representing gas flow from the compressor to the storage
5. Storage Component: Tracks the energy level in the storage over time
6. Discharge Edge: Internal edge representing gas flow from the storage to the compressor
7. Compressor Discharge Electricity Edge: Outgoing edge representing electricity consumption for gas discharge
8. Compressor Discharge Gas Edge: Outgoing edge representing gas flow from the storage to the system

Here is a graphical representation of the gas storage asset:

Flow Equations

The gas storage asset follows these flow relationships:

Compressor transformation:

\[\begin{aligned} \phi_{elec} &= \phi_{gas} \cdot \epsilon_{charge\_elec\_consumption} \quad \text{(charging)} \\ \phi_{elec} &= \phi_{gas} \cdot \epsilon_{discharge\_elec\_consumption} \quad \text{(discharging)} \\ \end{aligned}\]

Where:

• $\phi$ represents the flow of each commodity
• $\epsilon$ represents the stoichiometric coefficients defined in the table below (see table Conversion Process Parameters)

Input File (Standard Format)

The easiest way to include a gas storage 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/
│   ├── gas_storage.json    # or gas_storage.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 gas storage asset input file:

{
    "h2stor": [
        {
            "type": "GasStorage",
            "instance_data": [
                {
                    "id": "SE_Above_ground_storage",
                    "location": "SE",
                    "timedata": "Hydrogen",
                    "storage_commodity": "Hydrogen",
                    "storage_long_duration": true,
                    "storage_can_retire": false,
                    "storage_investment_cost": 873.01,
                    "storage_fixed_om_cost": 28.76,
                    "storage_loss_fraction": 0.0,
                    "storage_min_storage_level": 0.3,
                    "storage_constraints": {
                        "BalanceConstraint": true,
                        "MinStorageLevelConstraint": true
                    },
                    "discharge_can_retire": false,
                    "charge_can_retire": false,
                    "discharge_existing_capacity": 0,
                    "charge_existing_capacity": 0,
                    "discharge_investment_cost": 0.0,
                    "charge_investment_cost": 3219.24,
                    "discharge_electricity_consumption": 0.02,
                    "charge_electricity_consumption": 0.01,
                    "discharge_efficiency": 1.0,
                    "charge_efficiency": 1.0
                }
            ]
        }
    ]
}

The following tables outline the attributes that can be set for a gas storage asset.

Essential Attributes

Conversion Process Parameters

The following set of parameters control the conversion process and stoichiometry of the gas storage asset (see Flow Equations for more details).

Constraints Configuration

Gas storage 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 StorageCapacityConstraint, BalanceConstraint and MinStorageLevelConstraint to the storage component, and the RampingLimitConstraint to the discharge edge, the constraints fields should be set as follows:

{
    "storage_constraints": {
        "BalanceConstraint": true,
        "StorageCapacityConstraint": true,
        "MinStorageLevelConstraint": true
    },
    "discharge_constraints": {
        "RampingLimitConstraint": 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 a gas storage asset.

Default constraints

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

• Balance constraint (applied to the transformation component)
• Capacity constraint (applied to both charge and discharge edges)
• Storage capacity constraint (applied to the storage component)

If the storage is a long-duration storage (i.e., "storage_long_duration": true is set in the input file), the following additional constraints are applied by default:

• Long-duration storage constraints (applied to the storage component)

Investment Parameters

Additional Investment Parameters

Maximum and minimum capacity constraints

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

Economic Parameters

Charge and Discharge Efficiency

Operational Parameters

Additional Operational Parameters

Storage duration constraints

If StorageMaxDurationConstraint or StorageMinDurationConstraint are added to the constraints dictionary for the storage component, the following parameters are used:

Storage level constraints

If MaxStorageLevelConstraint or MinStorageLevelConstraint are added to the constraints dictionary for the storage component, the following parameters are used:

Minimum flow constraint

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

Ramping limit constraint

If RampingLimitConstraint is added to the constraints dictionary for the charge or discharge edges, the following parameters are used:

Types - Asset Structure

The GasStorage asset is defined as follows:

struct GasStorage{T} <: AbstractAsset
    id::AssetId
    pump_transform::Transformation
    gas_storage::AbstractStorage{<:T}
    charge_edge::Edge{<:T}
    discharge_edge::Edge{<:T}
    external_charge_edge::Edge{<:T}
    external_discharge_edge::Edge{<:T}
    charge_elec_edge::Edge{<:Electricity}
    discharge_elec_edge::Edge{<:Electricity}
end

Constructors

Default constructor

GasStorage(id::AssetId, pump_transform::Transformation, gas_storage::AbstractStorage{T}, charge_edge::Edge{T}, discharge_edge::Edge{T}, external_charge_edge::Edge{T}, external_discharge_edge::Edge{T}, charge_elec_edge::Edge{<:Electricity}, discharge_elec_edge::Edge{<:Electricity}) where {T<:Commodity}

Factory constructor

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

Examples

This section contains examples of how to use the gas storage asset in a Macro model.

Simple Gas Storage Asset

This example shows a new single asymmetric long-duration hydrogen storage asset located in the SE region with capacity that can only be expanded and not retired. The charge and discharge efficiency are set to 1.0, and the charge and discharge electricity consumption are set to 0.01 and 0.02, respectively. A MinStorageLevelConstraint constraint is applied to the storage component to ensure that the storage level is at least 30% of the capacity. A RampingLimitConstraint constraint is applied to the discharge edge with a ramping limit of 1.0. The storage component doesn't have losses.

JSON Format:

{
    "h2stor": [
        {
            "type": "GasStorage",
            "instance_data": [
                {
                    "id": "SE_Above_ground_storage",
                    "location": "SE",
                    "timedata": "Hydrogen",
                    "charge_electricity_consumption": 0.01,
                    "discharge_electricity_consumption": 0.02,
                    "storage_commodity": "Hydrogen",
                    "storage_long_duration": true,
                    "discharge_can_retire": false,
                    "discharge_existing_capacity": 0,
                    "discharge_investment_cost": 0.0,
                    "discharge_efficiency": 1.0,
                    "discharge_ramp_up_fraction": 1,
                    "discharge_ramp_down_fraction": 1,
                    "charge_can_retire": false,
                    "charge_existing_capacity": 0,
                    "charge_investment_cost": 3219.24,
                    "charge_efficiency": 1.0,
                    "storage_can_retire": false,
                    "storage_investment_cost": 873.01,
                    "storage_fixed_om_cost": 28.76,
                    "storage_loss_fraction": 0.0,
                    "storage_min_storage_level": 0.3,
                    "storage_constraints": {
                        "BalanceConstraint": true,
                        "StorageCapacityConstraint": true,
                        "MinStorageLevelConstraint": true
                    },
                    "discharge_constraints": {
                        "RampingLimitConstraint": true
                    }
                }
            ]
        }
    ]
}

CSV Format:

Multiple Hydrogen Storage Assets in Different Zones

This example shows how to create a set of new asymmetric long-duration hydrogen storage assets in different zones (SE, MIDAT, and NE), with different costs, capacities, and efficiency rates. Ramp rates and minimum storage levels are set to 1.0 and 0.3, respectively for all storage assets.

JSON Format:

Note that the global_data field is used to set the fields and constraints that are common to all instances of the same asset type.

{
    "h2stor": [
        {
            "type": "GasStorage",
            "global_data": {
                "timedata": "Hydrogen",
                "charge_electricity_consumption": 0.01,
                "discharge_electricity_consumption": 0.02,
                "storage_commodity": "Hydrogen",
                "storage_long_duration": true,
                "discharge_can_retire": false,
                "discharge_existing_capacity": 0,
                "discharge_investment_cost": 0.0,
                "discharge_efficiency": 1.0,
                "discharge_ramp_up_fraction": 1,
                "discharge_ramp_down_fraction": 1,
                "charge_can_retire": false,
                "charge_existing_capacity": 0,
                "charge_investment_cost": 3219.24,
                "charge_efficiency": 1.0,
                "storage_can_retire": false,
                "storage_investment_cost": 873.01,
                "storage_fixed_om_cost": 28.76,
                "storage_loss_fraction": 0.0,
                "storage_min_storage_level": 0.3,
                "storage_constraints": {
                    "BalanceConstraint": true,
                    "StorageCapacityConstraint": true,
                    "MinStorageLevelConstraint": true
                },
                "discharge_constraints": {
                    "RampingLimitConstraint": true
                }
            },
            "instance_data": [
                {
                    "id": "SE_Above_ground_storage",
                    "location": "SE"
                },
                {
                    "id": "MIDAT_Above_ground_storage",
                    "location": "MIDAT"
                },
                {
                    "id": "NE_Above_ground_storage",
                    "location": "NE"
                }
            ]
        }
    ]
}

CSV Format:

Best Practices

1. Use global data for common fields and constraints: Use the global_data field to set the fields and constraints that are common to all instances of the same asset type.
2. Set realistic efficiency values: Ensure charge and discharge efficiencies reflect actual technology performance
3. Use meaningful IDs: Choose descriptive identifiers that indicate location and storage type
4. Consider electricity consumption: Set appropriate electricity consumption for the compressor
5. Validate costs: Ensure investment and O&M costs are in appropriate units and time periods
6. Test configurations: Start with simple configurations and gradually add complexity
7. Set appropriate storage levels: Consider minimum storage levels for operational requirements

Input File (Advanced Format)

Macro provides an advanced format for defining gas storage 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 gas storage asset. The input file mirrors this hierarchical structure.

A gas storage asset in Macro is composed of a storage component, represented by a Storage object, a transformation component, represented by a Transformation object, and six edges, each represented by an Edge object. The input file for a gas storage asset is therefore organized as follows:

{
    "storage":{
        // ... storage-specific attributes ...
    },
    "transforms":{
        // ... transformation-specific attributes ...
    },
    "edges":{
        "charge_elec_edge": {
            // ... charge_elec_edge-specific attributes ...
        },
        "discharge_elec_edge": {
            // ... compressor_gas_edge-specific attributes ...
        },
        "charge_edge": {
            // ... charge_edge-specific attributes ...
        },
        "discharge_edge": {
            // ... discharge_edge-specific attributes ...
        },
        "external_charge_edge": {
            // ... external_charge_edge-specific attributes ...
        },
        "external_discharge_edge": {
            // ... external_discharge_edge-specific attributes ...
        }
    }
}

Each top-level key (e.g., "storage", "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 (e.g., "discharge_elec_edge", "charge_edge", etc.) when there are multiple instances. For multiple instances, a third-level key details the attributes for each instance.

Below is an example of an input file for a gas storage asset that sets a single instance of the asset in each of the three zones, SE, MIDAT, and NE.

{
    "h2stor": [
        {
            "type": "GasStorage",
            "global_data": {
                "transforms": {
                    "timedata": "Hydrogen",
                    "charge_electricity_consumption": 0.01,
                    "discharge_electricity_consumption": 0.02
                },
                "storage": {
                    "commodity": "Hydrogen",
                    "can_expand": true,
                    "can_retire": false,
                    "long_duration": true,
                    "investment_cost": 873.01,
                    "fixed_om_cost": 28.76,
                    "loss_fraction": 0.0,
                    "min_storage_level": 0.3,
                    "constraints": {
                        "StorageCapacityConstraint": true,
                        "BalanceConstraint": true,
                        "MinStorageLevelConstraint": true,
                        "LongDurationStorageImplicitMinMaxConstraint": true
                    }
                },
                "edges": {
                    "discharge_edge": {
                        "type": "Hydrogen",
                        "unidirectional": true,
                        "can_expand": true,
                        "can_retire": false,
                        "has_capacity": true,
                        "efficiency": 1.0,
                        "ramp_up_fraction": 1,
                        "ramp_down_fraction": 1,
                        "constraints": {
                            "CapacityConstraint": true,
                            "RampingLimitConstraint": true
                        }
                    },
                    "charge_edge": {
                        "type": "Hydrogen",
                        "unidirectional": true,
                        "has_capacity": true,
                        "can_expand": true,
                        "can_retire": false,
                        "investment_cost": 3219.24,
                        "efficiency": 1.0,
                        "constraints": {
                            "CapacityConstraint": true
                        }
                    },
                    "charge_elec_edge": {
                        "type": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "discharge_elec_edge": {
                        "type": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "external_charge_edge": {
                        "type": "Hydrogen",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "external_discharge_edge": {
                        "type": "Hydrogen",
                        "unidirectional": true,
                        "has_capacity": false
                    }
                }
            },
            "instance_data": [
                {
                    "id": "SE_Above_ground_storage",
                    "edges": {
                        "external_discharge_edge": {
                            "end_vertex": "h2_SE"
                        },
                        "external_charge_edge": {
                            "start_vertex": "h2_SE"
                        },
                        "discharge_elec_edge": {
                            "start_vertex": "elec_SE"
                        },
                        "charge_elec_edge": {
                            "start_vertex": "elec_SE"
                        }
                    }
                },
                {
                    "id": "MIDAT_Above_ground_storage",
                    "edges": {
                        "external_discharge_edge": {
                            "end_vertex": "h2_MIDAT"
                        },
                        "external_charge_edge": {
                            "start_vertex": "h2_MIDAT"
                        },
                        "discharge_elec_edge": {
                            "start_vertex": "elec_MIDAT"
                        },
                        "charge_elec_edge": {
                            "start_vertex": "elec_MIDAT"
                        }
                    }
                },
                {
                    "id": "NE_Above_ground_storage",
                    "edges": {
                        "external_discharge_edge": {
                            "end_vertex": "h2_NE"
                        },
                        "external_charge_edge": {
                            "start_vertex": "h2_NE"
                        },
                        "discharge_elec_edge": {
                            "start_vertex": "elec_NE"
                        },
                        "charge_elec_edge": {
                            "start_vertex": "elec_NE"
                        }
                    }
                }
            ]
        }
    ]
}

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, both charge and discharge edges can have capacity variables and constraints, representing the power capacity of the storage system (see note below).
• The storage component represents the energy capacity of the storage facility.
• For a comprehensive list of attributes that can be configured for the storage, transformation, and edge components, refer to the storage, transformation, and edges pages of the Macro manual.