Store - Inputs

Stores represent energy storage systems where energy capacity is the primary constraint. Below are all input attributes that you can set for store components.

Basic

Attribute	Data Type	Unit	Default	Required	Storage Type	Description
type	string	n/a	n/a	No	static	Placeholder for store type. Not yet implemented.
carrier	string	n/a	(empty)	No	static	Carrier type for the store (e.g. heat, gas, hydrogen). Used for categorization and energy balance constraints.
active	boolean	n/a	True	No	static	Whether this store is active and should be included in network calculations. Set to False to temporarily disable the store without deleting it.

Capacity

Attribute	Data Type	Unit	Default	Required	Storage Type	Description
e_nom	float	MWh	0	Yes	static	The maximum energy storage capacity of the store in MWh. This sets the upper limit for the amount of energy that can be stored.
e_nom_mod	float	MWh	0	No	static	The unit size for capacity expansion. When extending the nominal energy capacity (e_nom), it can only be increased in multiples of this module size.
e_nom_extendable	boolean	n/a	False	No	static	Switch to allow the nominal energy capacity (e_nom) to be extended in optimization.
e_nom_min	float	MWh	0	No	static	If the nominal energy capacity (e_nom) is extendable in optimization, set its minimum value.
e_nom_max	float	MWh	inf	No	static	If the nominal energy capacity (e_nom) is extendable in optimization, set its maximum value (e.g. limited by technical potential).
build_year	int	year	0	No	static	The year when the store can be built or commissioned. Essential for multi-year capacity expansion planning models, which determine optimal investment timing and store retirement schedules.
lifetime	float	years	inf	No	static	The operational lifetime of the store in years. Essential for multi-year capacity expansion planning models, which use this to determine when stores retire (build year + lifetime). Set to "inf" for stores that never retire.

Energy

Attribute	Data Type	Unit	Default	Required	Storage Type	Description
e_min_pu	float	per unit	0	No	static or timeseries	The minimum stored energy per unit of the nominal energy capacity (e_nom). Can be static or time-varying.
e_max_pu	float	per unit	1	No	static or timeseries	The maximum stored energy per unit of the nominal energy capacity (e_nom). Can be static or time-varying.
e_initial	float	MWh	0	No	static	The energy stored at the beginning of the optimization period, before the first snapshot. Ignored if cyclic energy (e_cyclic) is True.
e_initial_per_period	boolean	n/a	False	No	static	If True, the initial energy (e_initial) is applied at the beginning of each investment period separately, rather than only at the start of the entire optimization horizon.
e_cyclic	boolean	n/a	False	No	static	If True, the initial energy (e_initial) is ignored and the store must end with the same energy as it started (cyclic constraint). This ensures the store returns to its initial state at the end of the optimization period.
e_cyclic_per_period	boolean	n/a	True	No	static	If True, the cyclic energy constraint (e_cyclic) is applied to each investment period separately, rather than only to the entire optimization horizon.
standing_loss	float	per unit	0	No	static or timeseries	The self-discharge rate per hour, expressed as a fraction of the current stored energy. Represents energy losses that occur even when the store is idle (e.g., thermal losses, leakage). Can be time-varying.

Power Limits

Attribute	Data Type	Unit	Default	Required	Storage Type	Description
p_set	float	MW	0	No	static or timeseries	Fixed active power flow that the store must maintain (positive for withdrawing energy from the bus, negative for injecting energy into the bus). Used when the power flow is predetermined rather than optimized.
q_set	float	MVar	0	No	static or timeseries	Fixed reactive power flow that the store must maintain. Used when the reactive power flow is predetermined rather than optimized.
sign	float	n/a	1	No	static	Power flow direction convention: 1 for generation/discharging (positive power flows into the network), -1 for consumption/charging (positive power flows out of the network).

Costs

Attribute	Data Type	Unit	Default	Required	Storage Type	Description
marginal_cost	float	currency/MWh	0	No	static or timeseries	The variable cost applied to both charging and discharging 1 MWh of energy. Used by the optimizer to determine the economic dispatch order.
marginal_cost_quadratic	float	currency/MWh²	0	No	static or timeseries	Quadratic term for non-linear cost curves. When set, the total cost includes a quadratic component that increases with the square of energy flow, modeling increasing marginal costs at higher flow levels.
marginal_cost_storage	float	currency/MWh/h	0	No	static or timeseries	The variable cost of storing 1 MWh of energy for one hour. This represents the opportunity cost or wear-and-tear cost associated with storing energy in the store.
capital_cost	float	currency/MWh	0	No	static	The cost per MWh of adding new storage capacity. Includes investment costs (spread over the planning period) and fixed operations & maintenance costs. Only relevant when e_nom_extendable is True.