Lot of people assume that once a smart meter is installed, the reading errors go away. Not true. I just found a case with National Grid in upstate New York where the AMI meter was transmitting reads fine but the billing system was applying the reads to the wrong register. The meter had two registers — one for on-peak and one for off-peak on a TOU rate. The billing system had them swapped. Client was getting billed at the higher on-peak rate for the hours that were actually off-peak and vice versa. Since they used more energy during off-peak hours (night manufacturing), they were being significantly overbilled. The error started when the AMI meter was installed 18 months ago. Refund came to $14,200.
Smart meters are not immune to reading errors
I have seen this exact scenario with Duquesne Light. The register mapping issue is a known problem when utilities migrate from older meters to AMI. The physical meter records correctly but the head-end system that processes the data has the wrong register assignments. It is a database configuration error, not a meter error. And because the smart meter appears to be working fine, nobody investigates. Good catch.
Oncor had a batch of these in 2018. About 200 commercial accounts in the DFW area had their TOU registers swapped during the AMI migration. They caught it internally and issued corrections but only for 6 months back. If you have clients in Oncor territory on TOU rates who got new meters between 2017-2019, it might be worth checking if they were in the affected batch and whether the correction covered the full period.
Agreed Randy. My new standard practice for any TOU account with a recent meter change is to request the raw interval data from the AMI system and compare it to what shows on the bill. Takes about an hour per account but it catches these register mapping errors.