Working rural accounts in west Tennessee served by various co-ops — Chickasaw Electric, Southwest Tennessee EMC, Gibson EMC. Every single one has a different attitude about releasing data. Chickasaw was friendly and sent everything by email. Southwest Tennessee told me they'd never received a third-party request before and didn't know how to process it. Gibson wanted me to come in person with the client. There's no consistency whatsoever.
Requesting data from co-ops — they all seem to make up their own rules
Welcome to co-op territory. I deal with this in west Tennessee and Mississippi all the time. Co-ops are member-owned and governed by local boards so there's no state PUC oversight setting uniform rules. Each one does whatever their general manager decides. The good news is that because they're small and local, building a personal relationship with the billing clerk goes a long way. Once you've worked with a co-op once and they know you, subsequent requests are much easier. First time is always the hardest.
Beverly is right about the relationship factor with co-ops. Unlike IOUs where you're dealing with a corporate process, co-ops are community organizations. Introduce yourself, explain what you do in plain language, and be patient. Many co-op billing staff have never encountered a utility bill auditor. Once they understand you're trying to help their member-customer, they're usually cooperative. I also recommend attending your local co-op annual meetings if you work in co-op territory — great networking and it builds familiarity.