Electric DAC

Graph structure

An electric direct air capture (DAC) asset is represented in Macro using the following graph structure:

An electric DAC asset is made of:

1 Transformation component, representing the DAC process.
3 Edge components:
- 1 incoming Electricity Edge, representing the electricity consumption.
- 1 incoming CO2 Edge, representing the CO2 that is captured.
- 1 outgoing CO2 Captured Edge, representing the CO2 that is captured.

Attributes

The structure of the input file for an electric DAC asset follows the graph representation. Each global_data and instance_data will look like this:

{
    "transforms":{
        // ... transformation-specific attributes ...
    },
    "edges":{
        "elec_edge": {
            // ... elec_edge-specific attributes ...
        },
        "co2_edge": {
            // ... co2_edge-specific attributes ...
        },
        "co2_captured_edge": {
            // ... co2_captured_edge-specific attributes ...
        }
    }
}

Transformation

The definition of the transformation object can be found here MacroEnergy.Transformation.

Attribute	Type	Values	Default	Description/Units
timedata	`String`	`String`	Required	Time resolution for the time series data linked to the transformation. E.g. "Electricity".
constraints	`Dict{String,Bool}`	Any Macro constraint type for vertices	`BalanceConstraint`	List of constraints applied to the transformation. E.g. `{"BalanceConstraint": true}`.
electricity_consumption $\epsilon_{elec\_consumption}$	`Float64`	`Float64`	0.0	$MWh_{elec}/t_{CO2}$

Default constraints

The default constraint for the transformation part of the ElectricDAC asset is the following:

Balance constraint

Flow equations

In the following equations, $\phi$ is the flow of the commodity and $\epsilon$ is the stoichiometric coefficient defined in the transformation table below.

ElectricDAC

\[\begin{aligned} \phi_{elec} &= \phi_{co2\_captured} \cdot \epsilon_{elec\_consumption} \\ \phi_{co2} &= \phi_{co2\_captured} \\ \end{aligned}\]

Edge

Both the incoming and outgoing edges are represented by the same set of attributes. The definition of the Edge object can be found here MacroEnergy.Edge.

Attribute	Type	Values	Default	Description
type	`String`	Any Macro commodity type matching the commodity of the edge	Required	Commodity of the edge. E.g. "Electricity".
start_vertex	`String`	Any node id present in the system matching the commodity of the edge	Required	ID of the starting vertex of the edge. The node must be present in the `nodes.json` file. E.g. "elec_node_1".
end_vertex	`String`	Any node id present in the system matching the commodity of the edge	Required	ID of the ending vertex of the edge. The node must be present in the `nodes.json` file. E.g. "elec_node_2".
constraints	`Dict{String,Bool}`	Any Macro constraint type for Edges	Check box below	List of constraints applied to the edge. E.g. `{"CapacityConstraint": true}`.
availability	`Dict`	Availability file path and header	Empty	Path to the availability file and column name for the availability time series to link to the edge. E.g. `{"timeseries": {"path": "assets/availability.csv", "header": "Availability_MW_z1"}}`.
can_expand	`Bool`	`Bool`	`false`	Whether the edge is eligible for capacity expansion.
can_retire	`Bool`	`Bool`	`false`	Whether the edge is eligible for capacity retirement.
capacity_size	`Float64`	`Float64`	`1.0`	Size of the edge capacity.
existing_capacity	`Float64`	`Float64`	`0.0`	Existing capacity of the edge in MW.
fixed_om_cost	`Float64`	`Float64`	`0.0`	Fixed operations and maintenance cost (USD/MW-year).
has_capacity	`Bool`	`Bool`	`false`	Whether capacity variables are created for the edge.
integer_decisions	`Bool`	`Bool`	`false`	Whether capacity variables are integers.
investment_cost	`Float64`	`Float64`	`0.0`	Annualized capacity investment cost (USD/MW-year)
loss_fraction	`Float64`	Number $\in$ [0,1]	`0.0`	Fraction of transmission loss.
max_capacity	`Float64`	`Float64`	`Inf`	Maximum allowed capacity of the edge (MW). Note: add the `MaxCapacityConstraint` to the constraints dictionary to activate this constraint.
min_capacity	`Float64`	`Float64`	`0.0`	Minimum allowed capacity of the edge (MW). Note: add the `MinCapacityConstraint` to the constraints dictionary to activate this constraint.
min_flow_fraction	`Float64`	Number $\in$ [0,1]	`0.0`	Minimum flow of the edge as a fraction of the total capacity. Note: add the `MinFlowConstraint` to the constraints dictionary to activate this constraint.
ramp_down_fraction	`Float64`	Number $\in$ [0,1]	`1.0`	Maximum decrease in flow between two time steps, reported as a fraction of the capacity. Note: add the `RampingLimitConstraint` to the constraints dictionary to activate this constraint.
ramp_up_fraction	`Float64`	Number $\in$ [0,1]	`1.0`	Maximum increase in flow between two time steps, reported as a fraction of the capacity. Note: add the `RampingLimitConstraint` to the constraints dictionary to activate this constraint.
unidirectional	`Bool`	`Bool`	`false`	Whether the edge is unidirectional.
variable_om_cost	`Float64`	`Float64`	`0.0`	Variable operation and maintenance cost (USD/MWh).

Default constraints

The only default constraint for the edges of the ElectricDAC asset is the Capacity constraint applied to the CO2 edge.

Example

The following is an example of the input file for an ElectricDAC asset that creates three electric DAC units, each for a different region.

{
    "ElectricDAC": [
        {
            "type": "ElectricDAC",
            "global_data": {
                "transforms": {
                    "timedata": "Electricity",
                    "constraints": {
                        "BalanceConstraint": true
                    }
                },
                "edges": {
                    "co2_edge": {
                        "type": "CO2",
                        "unidirectional": true,
                        "has_capacity": true,
                        "start_vertex": "co2_sink",
                        "can_retire": true,
                        "can_expand": true,
                        "uc": false,
                        "constraints": {
                            "CapacityConstraint": true,
                            "RampingLimitConstraint": true
                        },
                        "integer_decisions": false
                    },
                    "elec_edge": {
                        "type": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_captured_edge": {
                        "type": "CO2Captured",
                        "unidirectional": true,
                        "has_capacity": false,
                        "end_vertex": "co2_captured_sink"
                    }
                }
            },
            "instance_data": [
                {
                    "id": "SE_Solvent_DAC",
                    "transforms": {
                        "electricity_consumption": 4.38
                    },
                    "edges": {
                        "co2_edge": {
                            "availability": {
                                "timeseries": {
                                    "path": "assets/availability.csv",
                                    "header": "SE_Solvent_DAC"
                                }
                            },
                            "existing_capacity": 0.0,
                            "investment_cost": 939000.00,
                            "fixed_om_cost": 747000.00,
                            "variable_om_cost": 22.00,
                            "ramp_up_fraction": 1.0,
                            "ramp_down_fraction": 1.0
                        },
                        "elec_edge": {
                            "start_vertex": "elec_SE"
                        }
                    }
                },
                {
                    "id": "MIDAT_Solvent_DAC",
                    "transforms": {
                        "electricity_consumption": 4.38
                    },
                    "edges": {
                        "co2_edge": {
                            "availability": {
                                "timeseries": {
                                    "path": "assets/availability.csv",
                                    "header": "MIDAT_Solvent_DAC"
                                }
                            },
                            "existing_capacity": 0.0,
                            "investment_cost": 939000.00,
                            "fixed_om_cost": 747000.00,
                            "variable_om_cost": 22.00,
                            "ramp_up_fraction": 1.0,
                            "ramp_down_fraction": 1.0
                        },
                        "elec_edge": {
                            "start_vertex": "elec_MIDAT"
                        }
                    }
                },
                {
                    "id": "NE_Solvent_DAC",
                    "transforms": {
                        "electricity_consumption": 4.38
                    },
                    "edges": {
                        "co2_edge": {
                            "availability": {
                                "timeseries": {
                                    "path": "assets/availability.csv",
                                    "header": "NE_Solvent_DAC"
                                }
                            },
                            "existing_capacity": 0.0,
                            "investment_cost": 939000.00,
                            "fixed_om_cost": 747000.00,
                            "variable_om_cost": 22.00,
                            "ramp_up_fraction": 1.0,
                            "ramp_down_fraction": 1.0
                        },
                        "elec_edge": {
                            "start_vertex": "elec_NE"
                        }
                    }
                }
            ]
        }
    ]
}