BECCS Electricity

Contents

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

Overview

BECCS Electricity assets in Macro represent Bioenergy with Carbon Capture and Storage (BECCS) technologies that produce electricity from biomass while capturing CO₂. These assets are defined using either JSON or CSV input files placed in the assets directory, typically named beccs_electricity.json or beccs_electricity.csv.

Asset Structure

A BECCS electricity asset consists of one transformation component and five edge components:

1. Biomass Edge: Incoming edge representing biomass supply
2. CO₂ Edge: Incoming edge representing CO₂ absorption from atmosphere
3. Transformation Component: Balances flows of biomass, CO₂, electricity, and CO₂ captured
4. Electricity Edge: Outgoing edge representing electricity production
5. CO₂ Emission Edge: Outgoing edge representing CO₂ emissions from the process
6. CO₂ Captured Edge: Outgoing edge representing captured CO₂

Here is a graphical representation of the BECCS electricity asset:

Flow Equations

The BECCS electricity asset follows these stoichiometric relationships:

\[\begin{aligned} \phi_{elec} &= \phi_{biomass} \cdot \epsilon_{elec\_prod} \\ \phi_{co2} &= \phi_{biomass} \cdot \epsilon_{co2\_content} \\ \phi_{co2\_emitted} &= \phi_{biomass} \cdot \epsilon_{emission\_rate} \\ \phi_{co2\_captured} &= \phi_{biomass} \cdot \epsilon_{capture\_rate} \\ \end{aligned}\]

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 BECCS electricity 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/
│   ├── beccs_electricity.json    # or beccs_electricity.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 BECCS electricity asset input file:

{
    "BECCS_Electricity": [
        {
            "type": "BECCSElectricity",
            "global_data": {
                "biomass_constraints": {
                    "MinFlowConstraint": true
                },
                "capacity_size": 400,
                "investment_cost": 765260.16,
                "fixed_om_cost": 212409.12,
                "variable_om_cost": 47.2,
                "emission_rate": 0.116756,
                "co2_content": 1.717,
                "capture_rate": 1.600244,
                "electricity_production": 1.606568331,
                "min_flow_fraction": 0.4,
                "co2_sink": "co2_sink"
            },
            "instance_data": [
                {
                    "id": "SE_BECCS_Electricity_Herb",
                    "location": "SE",
                    "biomass_commodity": "Biomass_Herb",
                    "availability": {
                        "timeseries": {
                            "path": "system/availability.csv",
                            "header": "SE_BECCS_Electricity_Herb"
                        }
                    }
                }
            ]
        }
    ]
}

The following tables outline the attributes that can be set for a BECCS electricity asset.

Essential Attributes

Conversion Process Parameters

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

Constraints Configuration

BECCS electricity 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 biomass edge, the constraints fields should be set as follows:

{
    "transform_constraints": {
        "BalanceConstraint": true
    },
    "biomass_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 BECCS electricity asset.

Default constraints

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

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

Investment Parameters

Additional Investment Parameters

Maximum and minimum capacity constraints

If MaxCapacityConstraint or MinCapacityConstraint are added to the constraints dictionary for the biomass 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 biomass edge, the following parameter is used:

Types - Asset Structure

The BECCSElectricity asset is defined as follows:

struct BECCSElectricity <: AbstractAsset
    id::AssetId
    beccs_transform::Transformation
    biomass_edge::Edge{<:Biomass}
    elec_edge::Edge{<:Electricity}
    co2_edge::Edge{<:CO2}
    co2_emission_edge::Edge{<:CO2}
    co2_captured_edge::Edge{<:CO2Captured}
end

Constructors

Default constructor

BECCSElectricity(id::AssetId, beccs_transform::Transformation, biomass_edge::Edge{<:Biomass}, co2_edge::Edge{<:CO2}, elec_edge::Edge{<:Electricity}, co2_captured_edge::Edge{<:CO2Captured}, co2_emission_edge::Edge{<:CO2})

Factory constructor

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

Examples

This section contains examples of how to use the BECCS electricity asset in a Macro model.

Simple BECCS Electricity Asset

This example shows a single BECCS electricity asset with existing capacity using Biomass_Herb as the biomass commodity.

JSON Format:

{
    "BECCS_Electricity": [
        {
            "type": "BECCSElectricity",
            "instance_data": [
                {
                    "id": "Fixed_BECCS_Electricity_SE",
                    "location": "SE",
                    "biomass_commodity": "Biomass_Herb",
                    "co2_sink": "co2_sink",
                    "electricity_production": 1.6,
                    "capture_rate": 1.5,
                    "co2_content": 1.8,
                    "emission_rate": 0.3,
                    "existing_capacity": 500.0,
                    "fixed_om_cost": 150000.0,
                    "variable_om_cost": 40.0
                }
            ]
        }
    ]
}

CSV Format:

Two BECCS Electricity Assets in the SE Region

This example shows two BECCS electricity assets in the SE region with different biomass types. The biomass constraints are set to the MinFlowConstraint constraint with a minimum flow fraction of 0.4, and the availability time series are set to the SE_BECCS_Electricity_Herb and SE_BECCS_Electricity_Wood time series.

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.

{
    "BECCS_Electricity": [
        {
            "type": "BECCSElectricity",
            "global_data": {
                "biomass_constraints": {
                    "MinFlowConstraint": true
                },
                "co2_sink": "co2_sink",
                "electricity_production": 1.606568331,
                "capture_rate": 1.600244,
                "co2_content": 1.717,
                "emission_rate": 0.116756,
                "investment_cost": 765260.16,
                "fixed_om_cost": 212409.12,
                "variable_om_cost": 47.2,
                "capacity_size": 400,
                "min_flow_fraction": 0.4
            },
            "instance_data": [
                {
                    "id": "SE_BECCS_Electricity_Herb",
                    "location": "SE",
                    "biomass_commodity": "Biomass_Herb",
                    "availability": {
                        "timeseries": {
                            "path": "system/availability.csv",
                            "header": "SE_BECCS_Electricity_Herb"
                        }
                    }
                },
                {
                    "id": "SE_BECCS_Electricity_Wood",
                    "location": "SE",
                    "biomass_commodity": "Biomass_Wood",
                    "availability": {
                        "timeseries": {
                            "path": "system/availability.csv",
                            "header": "SE_BECCS_Electricity_Wood"
                        }
                    }
                }
            ]
        }
    ]
}

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 stoichiometric coefficients: Ensure the transformation parameters reflect actual technology performance
3. Use meaningful IDs: Choose descriptive identifiers that indicate location and biomass type
4. Consider availability profiles: Use availability time series to model seasonal variations in biomass supply
5. Validate costs: Ensure investment and O&M costs are in appropriate units
6. Test configurations: Start with simple configurations and gradually add complexity
7. Monitor CO₂ balance: Ensure the CO₂ capture and emission rates are consistent with the overall system CO₂ balance

Input File (Advanced Format)

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

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

{
    "transforms":{
        // ... transformation-specific attributes ...
    },
    "edges":{
        "biomass_edge": {
            // ... biomass_edge-specific attributes ...
        },
        "co2_edge": {
            // ... co2_edge-specific attributes ...
        },
        "elec_edge": {
            // ... elec_edge-specific attributes ...
        },
        "co2_emission_edge": {
            // ... co2_emission_edge-specific attributes ...
        },
        "co2_captured_edge": {
            // ... co2_captured_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 (e.g., "biomass_edge", "elec_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 BECCS electricity asset that sets up a single asset in the SE region with detailed edge specifications.

{
    "BECCS_Electricity": [
        {
            "type": "BECCSElectricity",
            "global_data": {
                "transforms": {
                    "commodity": "Biomass",
                    "timedata": "Biomass",
                    "constraints": {
                        "BalanceConstraint": true
                    }
                },
                "edges": {
                    "biomass_edge": {
                        "type": "Biomass",
                        "unidirectional": true,
                        "has_capacity": true,
                        "can_expand": true,
                        "can_retire": true,
                        "constraints": {
                            "CapacityConstraint": true,
                            "MinFlowConstraint": true
                        }
                    },
                    "co2_edge": {
                        "type": "CO2",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "elec_edge": {
                        "type": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_captured_edge": {
                        "type": "CO2Captured",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_emission_edge": {
                        "type": "CO2",
                        "unidirectional": true,
                        "has_capacity": false
                    }
                }
            },
            "instance_data": [
                {
                    "id": "SE_BECCS_Electricity_Herb",
                    "transforms": {
                        "electricity_production": 1.656626506,
                        "capture_rate": 1.5313914,
                        "co2_content": 1.76022,
                        "emission_rate": 0.2288286
                    },
                    "edges": {
                        "biomass_edge": {
                            "start_vertex": "bioherb_SE",
                            "availability": {
                                "timeseries": {
                                    "path": "assets/availability.csv",
                                    "header": "SE_BECCS_Electricity_Herb"
                                }
                            },
                            "existing_capacity": 0.0,
                            "investment_cost": 696050.2868,
                            "fixed_om_cost": 193228.9157,
                            "variable_om_cost": 42.93975904,
                            "capacity_size": 400,
                            "min_flow_fraction": 0.4
                        },
                        "co2_edge": {
                            "start_vertex": "co2_sink"
                        },
                        "elec_edge": {
                            "end_vertex": "elec_SE"
                        },
                        "co2_captured_edge": {
                            "end_vertex": "co2_captured_sink"
                        },
                        "co2_emission_edge": {
                            "end_vertex": "co2_sink"
                        }
                    }
                }
            ]
        }
    ]
}

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 biomass edge is allowed to have capacity variables and constraints, as this represents the main capacity decision for the BECCS facility. However, the user can add capacity variables and constraints to the other edges as well (see note below).
• The biomass edge uses availability time series to model seasonal variations in biomass supply.
• 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.