## Energy Management

Energy management can be used, for example, to optimize the self-consumption of solar energy, limit power consumption, or control consumers depending on the price.
It can also be used for grid-supportive control of controllable consumption devices in accordance with Section 14a EnWG. The applicable statutory and technical requirements as well as the grid operator's specifications must be observed.
The desired operating mode is selected using the *Energy management type* parameter.
*Universal* is the fully configurable basic energy-management function.
The *Optimize self-consumption*, *Limit power consumption*, and *Optimize costs* types are simplified configurations of *Universal*.
For these types, suitable input and switching parameters are fixed and are therefore not displayed in ETS.

*Universal*: The *Input value* can be freely selected from the available measured values, energy prices, or an external communication object.
For an external communication object, its datapoint type is specified using *CO type*.
The *Upper threshold* and *Lower threshold* form the switching range.
The *Trigger on* parameter determines whether stages are activated when the value exceeds or falls below the thresholds.
With *Enable objects for upper and lower threshold*, both thresholds can also be changed via communication objects.
All input and switching parameters can be freely configured for *Universal*.

*Optimize self-consumption*: This operating mode is used to switch on consumers when there is a generation surplus.
The *Threshold* is configured as a negative power value in W.
If the value falls below this threshold, the enabled stages can be activated.
As a simplified configuration of *Universal*, *Input value* = *Active power 3ϕ (W)*, *Trigger on* = *Underrun*, *Upper threshold* = 0 W, and *Delay between switching stages* = 60 s are fixed.

*Limit power consumption*: This operating mode is used for load shedding when power consumption is high.
For grid-supportive operation in accordance with Section 14a EnWG, this type can, for example, limit the charging power of several wallboxes in stages so that a specified maximum power draw at the grid connection point is maintained.
Stages can be activated when the *Upper threshold* is exceeded.
They can be deactivated again after the value falls below the *Lower threshold*.
The two thresholds in W form a hysteresis and thus prevent frequent switching near the power limit.
As a simplified configuration of *Universal*, *Input value* = *Active power 3ϕ (W)*, *Trigger on* = *Exceedance*, and *Delay between switching stages* = 60 s are fixed.

*Optimize costs*: This operating mode is used to activate stages depending on the price.
If the price falls below the *Threshold* configured in ct/kWh, the enabled stages can be activated.
Two identical thresholds are used for switching on and off, so this operating mode works without hysteresis.
The *Threshold* can also be changed via the *Energy management 1 threshold* communication object.
As a simplified configuration of *Universal*, *Input value* = *Price energy consumption*, *Trigger on* = *Underrun*, *Upper threshold* = *Lower threshold* = *Threshold*, and *Delay between switching stages* = 60 s are fixed.

If *Enable lock object* is enabled, the entire energy management can be locked via the *Lock* communication object.
The *Polarity of lock object* parameter specifies which object value activates the lock.

If the conditions of the selected operating mode are met, up to 6 stages can be switched on.
Which stage or stages are switched depends on active locks, dead time, remaining daily enable operations, and the priority of the stages.
As soon as the condition is no longer met, the stages are switched off in reverse order, taking the minimum runtime into account.

After one or more stages have been switched on or off, the next switching action is delayed by the *Delay between switching stages*.
Switching off by activating a lock is excluded from this.

Up to 4 telegrams can be triggered per stage for activation and deactivation.
For each telegram, it can be specified separately whether a value is sent on activation and/or deactivation.

The communication objects for the delay between stages, remaining runtime, remaining enable operations, dead time, and operating hours can send on change.
This makes the energy-management states available for visualization or further processing.

Practical examples of the simplified types:

For more detailed descriptions of the following practical examples, refer to the product manual.

*Optimize self-consumption*: An energy meter measures the power flow at the grid connection point of a PV system.
A positive measured value means power is being drawn from the grid, and a negative measured value means power is being fed into the public grid.
A 2 kW immersion heater is intended to use only the PV surplus.
The *Threshold* is set to -2.1 kW so that a small reserve is taken into account in addition to the power of the immersion heater.
At around 09:00, the measured value falls below -2.1 kW because the PV system feeds more than 2.1 kW of surplus power into the grid.
The energy management switches on the immersion heater, which consumes 2 kW of the surplus and reduces the feed-in accordingly.
When the PV power decreases in the afternoon, the measured value rises back toward 0 W.
When the measured value exceeds the fixed upper threshold of 0 W at around 17:00, power is drawn from the grid and the immersion heater is switched off.
The minimum runtime of 5 minutes prevents premature switch-off after activation.
The dead time of 5 minutes prevents immediate reactivation after switch-off.

*Limit power consumption*: Three wallboxes rated at 11 kW each share a common grid connection.
In this simplified example, the power measured at the common grid connection contains only the power of the wallboxes that are currently charging.
The transmitted power limits are maximum values, so a wallbox without a charging request continues to draw 0 kW.
Above 15 kW, the next limiting stage is activated, and below 10 kW, the most recently activated limiting stage is removed again.
At 09:00, only wallbox 1 is charging at 11 kW, and no limit is active.
At 10:00, wallbox 2 starts charging, initially resulting in a requested power of 22 kW.
The first limiting stage limits both wallboxes to 7.4 kW each and reduces the total power to 14.8 kW.
At 11:00, wallbox 3 starts charging, initially resulting in a requested power of 22.2 kW under the existing limit.
The second limiting stage limits all three wallboxes to 4.1 kW each and reduces the total power to 12.3 kW.
At 14:00, wallbox 1 ends its charging process, the second limiting stage is removed, and the two remaining wallboxes are each allowed 7.4 kW again.
At 15:00, wallbox 2 ends its charging process, the first limiting stage is removed, and wallbox 3 is allowed 11 kW again.
At 16:00, the final charging process also ends.

*Optimize costs*: The current price of a dynamic electricity tariff is provided to the energy management in ct/kWh.
The *Threshold* is set to 25 ct/kWh.
Below this threshold, the stage sends an economic enable signal, and above this threshold, it withdraws the enable signal.
At 06:00, the price is 39.8 ct/kWh, so the enable signal is switched off.
At around 08:00, the price falls below 25 ct/kWh and the enable signal is switched on.
The price remains below the threshold at midday, so the enable signal remains active.
At around 15:00, the price rises above 25 ct/kWh again and the enable signal is switched off.
At exactly 25 ct/kWh, the previous state is retained because switching only takes place when the value falls below or exceeds the threshold.
The identical switch-on and switch-off thresholds do not form a hysteresis band.
The enable signal allows the consumer to operate, but its actual start and power continue to be determined by its own control system.
