I just discovered that some of our Geist PDU's does not report power consumption to Observium. It is the model EM8/GM3P.
To get power values from EM8/GM3P the snmpwalk needs to be done with an "enterprise" argument. I have attached the two snmpwalk output.
snmpwalk_normal.txt: outputs generic SNMP
snmpwalk_enterprise.txt out with ampere information
I hope you can add this to observium at some point.