First - when you post code to the forum PLEASE enclose it in a preformatted text block (three backticks) spaces are VERY important in YAML and the forum formatting makes them next to impossible to read.
IO put it in mine and still throwing 0 (I dont have that sensor and default=0 does that) you can also shorthand this as float(0)
Then remove a few of your extra parenthesis for readability…
{{ states('sensor.pv_power_1') | float(0) }}
This should produce your number if its producing it - 0 if anything is wrong, unknown or unavailable. If you put that in and it’s still giving you issues - to determine if the error is the float filter or your sensor - just strip off the last part and see what the result is telling you…
Apologies for the formatting and thanks for your input. You will have guessed I’m no no expert with HA.
{{ states(‘sensor.pv_power_1’) }} returns a string, unknown
{{ states(‘sensor.pv_power_1’) | float(0) }} returns a number, 0
So it seems to me that the sensor readings are not actually being generated, however, when I go to Settings>Select the MQTT tab>Configure>Start Listening, I see that values for sensor.pv_power_1, together with all the other inverter & battery readings, are being continuously updated.
I’m obviously missing something basic here. Any further suggestions would be appreciated.