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Storage

EnGenericStorage

Bases: EnBaseModel

Represents a generic energy storage model with various attributes related to inputs, outputs, capacities, efficiencies, and losses.

This class models an energy storage system with different properties such as storage capacity, inflow and outflow conversions, losses, and investment options. The class is designed to handle energy optimization tasks and can be translated into an oemof (Open Energy Modelling Framework)-compatible GenericStorage object.

Attributes:

Name Type Description
label str

Default label for the energy storage instance.
inputs dict[str, EnFlow]

Dictionary representing inflows to the storage. Keys are the ending nodes of the inflows.
outputs dict[str, EnFlow]

Dictionary representing outflows from the storage. Keys are the ending nodes of the outflows.
nominal_storage_capacity float | EnInvestment

Absolute nominal storage capacity. This can be a fixed value or an EnInvestment object for investment optimization.
invest_relation_input_capacity float | None

Ratio between the investment variable of the input flow and the investment variable of the storage.
invest_relation_output_capacity float | None

Ratio between the investment variable of the output flow and the investment variable of the storage.
invest_relation_input_output float | None

Ratio between the investment variable of the output flow and the investment variable of the input flow. Used to fix relationships between flow investments.
initial_storage_level float | None

Relative storage content before the first timestep of optimization (value between 0 and 1). Cannot be used with investment mode in multi-period models.
balanced bool

Indicates whether the total inflow and outflow are balanced (coupling the storage level of the first and last time step).
loss_rate float | list[float]

Relative loss of storage content per hour.
fixed_losses_relative float | list[float] | None

Losses proportional to the nominal storage capacity but independent of storage content. Not supported in investment mode.
fixed_losses_absolute float | list[float] | None

Losses independent of both storage content and nominal storage capacity. Not supported in investment mode.
inflow_conversion_factor float | list[float]

Efficiency associated with inflow to the storage.
outflow_conversion_factor float | list[float]

Efficiency associated with outflow from the storage.
min_storage_level float | list[float]

Minimum storage level as a fraction of nominal storage capacity or invested capacity. Value between 0 and 1. Can be set for each timestep using a sequence.
max_storage_level float | list[float]

Maximum storage level as a fraction of nominal storage capacity or invested capacity. Value between 0 and 1. Can be set for each timestep using a sequence.
investment EnInvestment | None

Object determining whether nominal storage capacity is optimized. If used, nominal_storage_capacity should not be set.
storage_costs float | list[float] | None

Cost (per energy unit) for maintaining energy in the storage.
lifetime_inflow int | None

Lifetime of inflow, applicable for multi-period models with investment in storage capacity and defined invest_relation_input_capacity.
lifetime_outflow int | None

Lifetime of outflow, applicable for multi-period models with investment in storage capacity and defined invest_relation_output_capacity.
Source code in backend/app/ensys/components/genericstorage.py 
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class EnGenericStorage(EnBaseModel):
    """
    Represents a generic energy storage model with various attributes related to
    inputs, outputs, capacities, efficiencies, and losses.

    This class models an energy storage system with different properties such as
    storage capacity, inflow and outflow conversions, losses, and investment
    options. The class is designed to handle energy optimization tasks and can
    be translated into an oemof (Open Energy Modelling Framework)-compatible
    GenericStorage object.

    :ivar label: Default label for the energy storage instance.
    :ivar inputs: Dictionary representing inflows to the storage. Keys are the
        ending nodes of the inflows.
    :ivar outputs: Dictionary representing outflows from the storage. Keys are
        the ending nodes of the outflows.
    :ivar nominal_storage_capacity: Absolute nominal storage capacity. This can
        be a fixed value or an EnInvestment object for investment optimization.
    :ivar invest_relation_input_capacity: Ratio between the investment variable
        of the input flow and the investment variable of the storage.
    :ivar invest_relation_output_capacity: Ratio between the investment variable
        of the output flow and the investment variable of the storage.
    :ivar invest_relation_input_output: Ratio between the investment variable of
        the output flow and the investment variable of the input flow. Used to
        fix relationships between flow investments.
    :ivar initial_storage_level: Relative storage content before the first
        timestep of optimization (value between 0 and 1). Cannot be used with
        investment mode in multi-period models.
    :ivar balanced: Indicates whether the total inflow and outflow are balanced
        (coupling the storage level of the first and last time step).
    :ivar loss_rate: Relative loss of storage content per hour.
    :ivar fixed_losses_relative: Losses proportional to the nominal storage
        capacity but independent of storage content. Not supported in
        investment mode.
    :ivar fixed_losses_absolute: Losses independent of both storage content and
        nominal storage capacity. Not supported in investment mode.
    :ivar inflow_conversion_factor: Efficiency associated with inflow to the
        storage.
    :ivar outflow_conversion_factor: Efficiency associated with outflow from
        the storage.
    :ivar min_storage_level: Minimum storage level as a fraction of nominal
        storage capacity or invested capacity. Value between 0 and 1. Can be
        set for each timestep using a sequence.
    :ivar max_storage_level: Maximum storage level as a fraction of nominal
        storage capacity or invested capacity. Value between 0 and 1. Can be
        set for each timestep using a sequence.
    :ivar investment: Object determining whether nominal storage capacity is
        optimized. If used, nominal_storage_capacity should not be set.
    :ivar storage_costs: Cost (per energy unit) for maintaining energy in the
        storage.
    :ivar lifetime_inflow: Lifetime of inflow, applicable for multi-period
        models with investment in storage capacity and defined
        invest_relation_input_capacity.
    :ivar lifetime_outflow: Lifetime of outflow, applicable for multi-period
        models with investment in storage capacity and defined
        invest_relation_output_capacity.
    """
    label: str = Field(
        "Default GenericStorage",
        title='Label',
        description=''
    )

    inputs: dict[str, EnFlow] = Field(
        ...,
        title='Inputs',
        description='Dictionary with inflows. Keys must be the ending node(s) of the inflows(s)'
    )

    outputs: dict[str, EnFlow] = Field(
        ...,
        title='Outputs',
        description='Dictionary with outflows. Keys must be the ending node(s) of the outflow(s)'
    )
    nominal_storage_capacity: float | EnInvestment = Field(
        ...,
        title='nominal storage capacity',
        description='object Absolute nominal capacity of the storage, fixed value or object describing parameter of investment optimisations.'
    )

    invest_relation_input_capacity: float | None = Field(
        None,
        title='invest relation input capacity',
        description='Ratio between the investment variable of the input Flow and the investment variable of the storage'
    )

    invest_relation_output_capacity: float | None = Field(
        None,
        title='invest relation output capacity',
        description='Ratio between the investment variable of the output Flow and the investment variable of the storage.'
    )

    invest_relation_input_output: float | None = Field(
        None,
        title='invest relation input output',
        description='Ratio between the investment variable of the output Flow and the investment variable of the input flow. This ratio used to fix the flow investments to each other. Values < 1 set the input flow lower than the output and > 1 will set the input flow higher than the output flow.'
    )

    initial_storage_level: float | None = Field(
        None,
        title='initial storage level',
        description='The relative storage content in the timestep before the first time step of optimization (between 0 and 1). Note: When investment mode is used in a multi-period model, initial_storage_level is not supported. Storage output is forced to zero until the storage unit is invested in.'
    )

    balanced: bool = Field(
        True,
        title='balanced',
        description=' Couple storage level of first and last time step. (Total inflow and total outflow are balanced.)'
    )

    loss_rate: float | list[float] = Field(
        ...,
        title='loss rate',
        description='The relative loss of the storage content per hour.'
    )

    fixed_losses_relative: float | list[float] | None = Field(
        None,
        title='fixed losses relative',
        description='Losses per hour that are independent of the storage content but proportional to nominal storage capacity. Note: Fixed losses are not supported in investment mode.'
    )

    fixed_losses_absolute: float | list[float] | None = Field(
        None,
        title='Fixed losses absolute',
        description='Losses per hour that are independent of storage content and independent of nominal storage capacity. Note: Fixed losses are not supported in investment mode.'
    )

    inflow_conversion_factor: float | list[float] = Field(
        ...,
        title='Conversion factor: Inflow',
        description='The relative conversion factor, i.e. efficiency associated with the inflow of the storage.'
    )

    outflow_conversion_factor: float | list[float] = Field(
        ...,
        title='Conversion factor: Outflow',
        description='The relative conversion factor, i.e. efficiency associated with the outflow of the storage.'
    )

    min_storage_level: float | list[float] = Field(
        ...,
        title='Minimum storage level',
        description='The normed minimum storage content as fraction of the nominal storage capacity or the capacity that has been invested into (between 0 and 1). To set different values in every time step use a sequence.'
    )

    max_storage_level: float | list[float] = Field(
        ...,
        title='Maximum storage level',
        description='The normed maximum storage content as fraction of the nominal storage capacity or the capacity that has been invested into (between 0 and 1). To set different values in every time step use a sequence.'
    )

    investment: EnInvestment | None = Field(
        None,
        title='Investment',
        description='Object indicating if a nominal_value of the flow is determined by the optimization problem. Note: This will refer all attributes to an investment variable instead of to the nominal_storage_capacity. The nominal_storage_capacity should not be set (or set to None) if an investment object is used.'
    )

    storage_costs: float | list[float] | None = Field(
        None,
        title='storage costs',
        description='Cost (per energy) for having energy in the storage.'
    )

    lifetime_inflow: int | None = Field(
        None,
        title='lifetime inflow',
        description='Determine the lifetime of an inflow; only applicable for multi-period models which can invest in storage capacity and have an invest_relation_input_capacity defined.'
    )

    lifetime_outflow: int | None = Field(
        None,
        title='lifetime outflow',
        description='Determine the lifetime of an outflow; only applicable for multi-period models which can invest in storage capacity and have an invest_relation_output_capacity defined.'
    )


    def to_oemof(self, energysystem: solph.EnergySystem) -> solph.components.GenericStorage:
        """
        Converts the current storage object to an oemof-compatible
        GenericStorage component.

        This method takes an oemof EnergySystem object as input,
        builds the appropriate arguments for an oemof GenericStorage,
        and then returns the created GenericStorage component.

        :param energysystem: The specified oemof EnergySystem object required for
            creating the GenericStorage component.
        :type energysystem: solph.EnergySystem
        :return: A GenericStorage component created and populated
            using the provided EnergySystem and associated parameters.
        :rtype: solph.components.GenericStorage
        """
        kwargs = self.build_kwargs(energysystem)

        return solph.components.GenericStorage(**kwargs)

to_oemof(energysystem)

Converts the current storage object to an oemof-compatible GenericStorage component.

This method takes an oemof EnergySystem object as input, builds the appropriate arguments for an oemof GenericStorage, and then returns the created GenericStorage component.

Parameters:

Name Type Description Default
energysystem EnergySystem

The specified oemof EnergySystem object required for creating the GenericStorage component.

 required

Returns:

Type Description
solph.components.GenericStorage

A GenericStorage component created and populated using the provided EnergySystem and associated parameters.
Source code in backend/app/ensys/components/genericstorage.py 
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def to_oemof(self, energysystem: solph.EnergySystem) -> solph.components.GenericStorage:
    """
    Converts the current storage object to an oemof-compatible
    GenericStorage component.

    This method takes an oemof EnergySystem object as input,
    builds the appropriate arguments for an oemof GenericStorage,
    and then returns the created GenericStorage component.

    :param energysystem: The specified oemof EnergySystem object required for
        creating the GenericStorage component.
    :type energysystem: solph.EnergySystem
    :return: A GenericStorage component created and populated
        using the provided EnergySystem and associated parameters.
    :rtype: solph.components.GenericStorage
    """
    kwargs = self.build_kwargs(energysystem)

    return solph.components.GenericStorage(**kwargs)