Sensor not selectable in energy

hello everyone, i would like to display the sensor “sensor.stromzaehler_stromzaehler_sml2_power_curr”, which shows me the current power consumption, in energymonitor. unfortunately, this is not selectable.
I have already edited the configuration.yaml.

# MQTT-Integration
mqtt:


# Sensoren
sensor:
  - platform: mqtt
    name: "StromSML2"
    state_topic: "Strom/tele/SENSOR"
    unit_of_measurement: "W"
    device_class: energy
    state_class: total
    value_template: "{{ value_json.SML2.Power_curr }}"
    icon: mdi:home-lightning-bolt
    friendly_name: "StromSML2"

unfortunately, the sensor is still not displayed. even in the developertools I only see states:

unit_of_measurement:  
icon: mdi:home-lightning-bolt
friendly_name: StromSML2```

many thanks in advance!

Energy is not measured in Watts. That is a power sensor, you have the wrong device class. If it does not provide an energy sensor you will need to use the Integral helper to convert power to energy.