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Storage technologies

Storage technologies can store an energy carrier for later use. For example, batteries store electricity and a hot water buffer stores heat at a certain temperature level.

The capacity and operation of a storage technology are defined by these parameters:

  • Capacity: the maximum amount of energy that can be accumulated, expressed in kWh
  • Discharge rate: how fast the energy can be delivered, expressed in kW
  • State of charge (SoC): quantifies the remaining capacity available at a given time, expressed as a percentage of the capacity

Like conversion technologies, each candidate is defined by technical, financial, and environmental parameters.

Capacity

You can choose different sizing methods. The size of the storage technology is expressed in kWh:

  • Optimize capacity: Sympheny finds the optimal capacity.
  • Minimum and Maximum capacity: You can enter a minimum and/or maximum capacity bound.
  • Can be installed and Minimum capacity: If a minimum capacity is specified and the default option Default option toggle is toggled, the installed capacity can either be 0 or greater than the minimum.
  • Must be installed and Minimum capacity: The capacity must be greater than or equal to the minimum capacity.
  • Specify capacity: The installed capacity is fixed. If the default "can be installed" option is toggled, the capacity will be either 0 or the specified capacity.

Tip

For more advanced users, specifying a minimum and maximum capacity is good practice and often reduces computation time.

Maximum discharge rate

The discharge rate is modeled as a %/h of the capacity. For a 10 kWh battery, a discharge rate of 100%/h means the battery can deliver 100% of its capacity in one hour, equivalent to a power of 10 kW.

Efficiency

Losses can occur continuously or during charging and discharging. Standby losses are applied every hour relative to the state of charge. Charging and discharging losses are applied as a percentage of charge and discharge.

The minimum SoC (State of Charge) limits how much the storage can be discharged, effectively reducing the available capacity.

Costs and CO2

The installed capacity is used to calculate the investment, maintenance costs, and embodied emissions.