Client in Grand Rapids installed 8kW solar + 13.5kWh Powerwall in January. DTE Energy is completely botching the billing. They're double-charging for grid electricity when the battery discharges at night, then not crediting properly for solar exports during the day. The customer's bill actually went UP by $89/month after going solar. DTE claims their meters can't distinguish between battery discharge and grid consumption. This can't be legal, right?
Tesla Powerwall + Solar - DTE Billing Nightmare
Tina, we've seen similar issues with NorthWestern Energy here in Montana when battery storage is involved. The problem is most utilities' net metering tariffs were written before battery storage became common. They literally don't know how to bill it correctly. You need to get DTE to install a production meter separate from the net meter. That's the only way to properly track solar generation vs. battery discharge.
Had the exact same issue with NYSEG in Rochester last month. Customer had Enphase batteries and their bills were insane. The solution was getting them to install bidirectional metering under their Value Stack program. Took six phone calls and a complaint to the PSC, but they finally agreed to retrofit the proper meters at no charge.
This battery metering issue is becoming epidemic. Here in Memphis, MLGW still doesn't even have a battery storage tariff - they just pretend it doesn't exist. Tina, document every kWh discrepancy and demand DTE provide their methodology for calculating net usage. Under Michigan's net metering law, they're required to provide transparent billing calculations.
Randy, that's exactly what I needed to hear! Found the Michigan statute - PA 295 Section 6a(8) requires utilities to provide detailed calculation methodology. Filing a formal complaint with MPSC tomorrow. Tom, how long did the NYSEG meter retrofit take? My client is hemorrhaging money every month this drags on.
About 6 weeks from complaint filing to new meter installation. The key was demonstrating financial harm - customer was overpaying by $127/month due to incorrect metering. NYSEG suddenly found money in their budget for new meters when the PSC started asking questions. Make sure you calculate exact damages, not just "approximately."
Tina, I'm dealing with Duke Energy Ohio on a similar case in Cincinnati. They keep insisting their AMI meters can handle battery systems, but the bills prove otherwise. One thing that helped was getting the battery installer (Tesla in your case) to provide detailed export/import logs. Creates undeniable evidence of billing errors.
Chuck, great suggestion! Tesla's monitoring shows 1,247 kWh exported to grid in March, but DTE only credited 891 kWh. That's 356 kWh they just ignored - worth about $61. Combined with the double-billing on battery discharge, we're looking at $142/month in systematic errors. MPSC complaint filed this morning with full Tesla data logs attached.
Excellent work documenting the discrepancy, Tina. That level of detail makes it impossible for DTE to claim "meter error" or other BS excuses. Keep pushing - these battery storage billing issues affect all of us and we need utilities to get their act together before storage becomes mainstream.
Update: DTE agreed to install proper production metering and provide back-credits for the last 3 months. Total recovery: $426 plus ongoing savings of about $140/month. The MPSC complaint definitely got their attention. Thanks everyone for the advice - couldn't have done it without this forum!
Fantastic outcome, Tina! Another victory for the good guys. Your case just created precedent for every other DTE battery storage customer in Michigan. Well done.