Upstream Emissions

Contents

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

Overview

Upstream emissions assets in Macro represent upstream commodity supply processes where emissions are explicitly tracked. They take in a source commodity, pass that commodity into the modeled system, and route associated CO2 emissions to a sink according to an emission_rate. These assets are defined using either JSON or CSV input files placed in the assets directory, typically named with descriptive identifiers like upstreamemissions.json or upstreamemissions.csv.

The current implementation is generic over commodity type, so the same asset can represent upstream emissions for liquid fuels, natural gas, or other commodities supported by the model.

For backward compatibility, FossilFuelsUpstream remains available as an alias of UpstreamEmissions.

Asset Structure

An upstream emissions asset consists of four main components:

1. Transformation Component: Balances commodity throughput and emissions
2. Source Commodity Edge: Represents the incoming upstream commodity flow
3. Delivered Commodity Edge: Represents the outgoing commodity flow into the modeled system
4. CO2 Edge: Represents emitted CO2 sent to a sink or location

Here is a graphical representation of the upstream emissions asset:

Flow Equations

The upstream emissions asset follows these relationships:

\[\begin{aligned} \text{flow}_{fuel} &= \text{flow}_{source} \\ \text{flow}_{co2} &= \text{flow}_{source} \cdot \epsilon_{emission\_rate} \end{aligned}\]

Where:

• flow represents the flow of each commodity
• $\epsilon$ represents the emission coefficient defined in the Conversion Process Parameters section

Input File (Standard Format)

The easiest way to include an upstream emissions 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/
│   ├── upstreamemissions.json    # or upstreamemissions.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 an upstream emissions asset input file:

{
    "upstream_emissions": [
        {
            "type": "UpstreamEmissions",
            "instance_data": [
                {
                    "id": "liquid_fuels_supply_SE",
                    "location": "SE",
                    "fuel_commodity": "LiquidFuels",
                    "fossil_fuel_commodity": "LiquidFuels",
                    "emission_rate": 0.25,
                    "fuel_investment_cost": 2500,
                    "fuel_fixed_om_cost": 100,
                    "fuel_variable_om_cost": 2.0,
                    "co2_sink": "co2_atm_SE"
                }
            ]
        }
    ]
}

The following tables outline the attributes that can be set for an upstream emissions asset.

Essential Attributes

Conversion Process Parameters

Simple-format edge attributes use edge-specific prefixes. For example, delivered commodity edge fields are written as fuel_investment_cost, fuel_existing_capacity, and fuel_constraints; source commodity edge fields use the fossil_fuel_ prefix; and CO2 edge fields use the co2_ prefix.

Constraints Configuration

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

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 an upstream emissions asset.

Default constraints

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

• Balance constraint (applied to the transformation component)

Investment Parameters

Additional Investment Parameters

Maximum and minimum capacity constraints

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

Economic Parameters

Operational Parameters

Additional Operational Parameters

Minimum flow constraint

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

Ramping limit constraint

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

Types - Asset Structure

The UpstreamEmissions asset is defined as follows:

struct UpstreamEmissions{T} <: AbstractAsset
    id::AssetId
    fossilfuelsupstream_transform::Transformation
    fossil_fuel_edge::Edge{<:T}
    fuel_edge::Edge{<:T}
    co2_edge::Edge{<:CO2}
end

const FossilFuelsUpstream = UpstreamEmissions

Constructors

Default constructors

UpstreamEmissions(
    id::AssetId,
    fossilfuelsupstream_transform::Transformation,
    fossil_fuel_edge::Edge{<:T},
    fuel_edge::Edge{<:T},
    co2_edge::Edge{<:CO2}
) where {T<:LiquidFuels}

UpstreamEmissions(
    id::AssetId,
    fossilfuelsupstream_transform::Transformation,
    fossil_fuel_edge::Edge{<:T},
    fuel_edge::Edge{T},
    co2_edge::Edge{<:CO2}
) where {T<:Commodity}

Factory constructor

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

Examples

This section contains examples of how to use the upstream emissions asset in a Macro model.

Multiple upstream emissions assets with shared defaults

This example shows how to create two upstream emissions assets in different zones with shared global data and zone-specific emission_rate and cost assumptions.

JSON Format:

{
    "upstream_emissions": [
        {
            "type": "UpstreamEmissions",
            "global_data": {
                "fuel_commodity": "NaturalGas",
                "fossil_fuel_commodity": "NaturalGas",
                "fuel_variable_om_cost": 1.0,
                "co2_sink": "co2_atm"
            },
            "instance_data": [
                {
                    "id": "natgas_supply_SE",
                    "location": "SE",
                    "emission_rate": 0.18,
                    "fuel_investment_cost": 1200,
                    "fuel_fixed_om_cost": 80
                },
                {
                    "id": "natgas_supply_NE",
                    "location": "NE",
                    "emission_rate": 0.16,
                    "fuel_investment_cost": 1500,
                    "fuel_fixed_om_cost": 95
                }
            ]
        }
    ]
}

CSV Format:

Best Practices

1. Use explicit commodity names for both fuel_commodity and fossil_fuel_commodity, even when they are the same.
2. Set co2_sink explicitly when emissions should be routed to a dedicated CO2 node rather than the asset location.
3. Keep emission_rate units consistent with the commodity flow units used in the rest of the model.
4. Use global_data for shared cost and commodity settings when creating many upstream emissions assets.
5. If this asset represents a physical import interface, apply capacity and ramping constraints on the delivered commodity edge rather than the transformation.

Input File (Advanced Format)

Macro provides an advanced format for defining upstream emissions assets, offering users and modelers detailed control over transformation and edge specifications.

To understand the advanced format, consider the graph representation and the type definition of an upstream emissions asset. The input file mirrors this hierarchical structure.

An upstream emissions asset in Macro is composed of a Transformation object and three Edge objects. The input file for an upstream emissions asset is therefore organized as follows:

{
    "transforms": {
        // ... transformation-specific attributes ...
    },
    "edges": {
        "fossil_fuel_edge": {
            // ... source commodity edge-specific attributes ...
        },
        "fuel_edge": {
            // ... delivered commodity edge-specific attributes ...
        },
        "co2_edge": {
            // ... CO2 edge-specific attributes ...
        }
    }
}

Below is an example of an advanced input file for an upstream emissions asset:

{
    "upstream_emissions": [
        {
            "type": "UpstreamEmissions",
            "instance_data": [
                {
                    "id": "liquid_fuels_supply_SE",
                    "location": "SE",
                    "transforms": {
                        "timedata": "LiquidFuels",
                        "emission_rate": 0.25,
                        "constraints": {
                            "BalanceConstraint": true
                        }
                    },
                    "edges": {
                        "fossil_fuel_edge": {
                            "commodity": "LiquidFuels",
                            "start_vertex": "liquid_fuels_source_SE"
                        },
                        "fuel_edge": {
                            "commodity": "LiquidFuels",
                            "end_vertex": "liquid_fuels_SE",
                            "investment_cost": 2500,
                            "fixed_om_cost": 100,
                            "variable_om_cost": 2.0
                        },
                        "co2_edge": {
                            "commodity": "CO2",
                            "end_vertex": "co2_atm_SE"
                        }
                    }
                }
            ]
        }
    ]
}

Key Points

• The transforms block configures the internal transformation object, including timedata, constraints, and emission_rate.
• The fossil_fuel_edge and fuel_edge can be assigned any supported commodity type, allowing the asset to model upstream emissions for multiple sectors.