Adding Policy Constraints to a System

Currently, Macro supports two types of policy constraints:

• CO₂ cap constraint
• CO₂ storage annual constraint

The units of both constraints are determined by the stoichiometric balances used in assets with CO₂ emissions or injection to a CO₂ capture node.

The following sections describe the steps to add these constraints to a system:

• Adding a CO₂ cap constraint
• Adding a CO₂ storage annual constraint

Adding a CO₂ cap constraint

To add a CO₂ cap constraint to a CO₂ node in a system, the user needs to:

1. Activate the constraint by setting CO2CapConstraint to true in the constraints field of a node of type CO2 in the nodes file:

{
    "constraints": {
        "CO2CapConstraint": true
    }
}

2. Set the CO₂ cap value using the CO2CapConstraint key in the rhs_policy field:

{
    "rhs_policy": {
        "CO2CapConstraint": 0   // e.g. zero emissions
    }
}

3. (Optional) Add a carbon price penalty using the price_unmet_policy field:

{
    "price_unmet_policy": {
        "CO2CapConstraint": 200  // e.g. 200 USD/tonne penalty cost
    }
}

As a result, to add a CO₂ cap constraint to a CO2 node in a system, the nodes file should have a CO2 node with the following structure:

{
    "type": "CO2",
    "instance_data": [
        {
            "id": "co2_sink",
            "constraints": {
                "CO2CapConstraint": true
            },
            "rhs_policy": {
                "CO2CapConstraint": 0
            },
            "price_unmet_policy": {
                "CO2CapConstraint": 200
            }
        },
        // other CO2 nodes
    ],
    "global_data": {
        // other attributes
    }
}

4. Link the CO₂ node's id to the co2_sink key of assets in the system that have CO₂ emissions to track their CO₂ output:

{
    "type": "ThermalPower",
    "instance_data": [
        {
            "co2_sink": "co2_sink",
            // other attributes
        }
    ],
    "global_data": {
        // other attributes
    }
}

Macro will automatically track all CO₂ emissions from assets connected to the co2_sink node and will constrain total emissions to the value specified in the rhs_policy key (unless a carbon price penalty is applied using the price_unmet_policy field).

Adding a CO₂ storage annual constraint

The CO₂ storage annual constraint limits the amount of CO₂ that can be injected and stored in a CO2Captured node.

To add a CO₂ storage annual constraint to a CO2Captured node in a system, the user needs to:

1. Activate the constraint by setting CO2StorageConstraint to true in the constraints key of a node of type CO2Captured:

{
    "constraints": {
        "CO2StorageConstraint": true
    }
}

2. Set the CO₂ storage annual constraint value using the CO2StorageConstraint key in the rhs_policy field:

{
    "rhs_policy": {
        "CO2StorageConstraint": 4753600
    }
}

Consequently, the nodes.json file should have a CO2Captured node with the following structure:

{
    "type": "CO2Captured",
    "instance_data": [
        {
            "id": "co2_storage_1",
            "constraints": {
                "CO2StorageConstraint": true
            },
            "rhs_policy": {
                "CO2StorageConstraint": 4753600
            }
        },
        // other CO2Captured nodes
    ],
    "global_data": {
        // other attributes
    }
}

3. Link the CO2Captured node's id to the co2_storage key of assets in the system with CO₂ storage edges to track their CO₂ storage:

{
    "type": "CO2Injection",
    "instance_data": [
        {
            "co2_storage": "co2_storage_1",
            // other attributes
        }
    ],
    "global_data": {
        // other attributes
    }
}

Macro will automatically track all CO₂ injection from assets linked to the co2_storage node and constrain the total injection to the value set in the rhs_policy key.