Client in Savannah installed 8kW solar system six months ago under Georgia Power's net metering program. Now they're getting hit with demand charges that never appeared before. The solar reduces their energy consumption during peak sun hours but apparently their peak demand is still hitting in the evening when solar production drops off. Is this normal? Schedule R-25 shows demand charges starting at 10kW but this customer never hit that threshold before installing solar.
Georgia Power demand charges on solar accounts - need advice
Eleanor, that's a classic issue with TOU metering and solar. The solar production creates a valley in their daytime usage but evening load remains the same, making the demand profile more "peaky". Some utilities use this to justify moving solar customers to demand-based rates. Check if Georgia Power automatically switched them to a different rate schedule when they interconnected the solar system.
We see this with AEP Texas too. The utility argues that solar customers still need the full grid infrastructure available during peak times so they should pay demand charges. Problem is they don't tell customers about this when they sign up for net metering. Eleanor, was your client given proper notice about rate schedule changes? Texas requires 30 days written notice.
I've battled Alabama Power on this exact issue. They have a nasty habit of moving solar customers to Schedule LGS (Large General Service) which has demand charges, claiming the solar system makes them "commercial". Pure nonsense - a residential customer with rooftop solar is still residential. Eleanor, check what rate schedule they moved your client to and demand justification in writing.
Up here with Idaho Power, they have a specific solar rate schedule that includes demand charges but caps them at reasonable levels. The key is understanding the load profile before and after solar installation. Eleanor, do you have 12 months of pre-solar billing data to compare? Sometimes the demand charges were already there but buried in the energy charges.
Thanks everyone. Albert, you're right - they moved the customer from Schedule R-6 to R-25 without proper notification. The interconnection agreement mentioned "applicable rate schedules" but didn't specify the change. The pre-solar bills show they occasionally hit 9.5kW demand but never crossed the 10kW threshold for demand charges. Now they're consistently showing 11-12kW demand in the evenings.
Eleanor, that demand increase might not be real load growth. Some utilities change the demand measurement methodology when solar is installed - instead of 15-minute intervals they switch to 5-minute intervals which can artificially inflate demand readings. Duke Energy tried this trick in Ohio. Request the raw interval data and verify the measurement method hasn't changed.
Cecilia raises an excellent point. APS pulled similar shenanigans here - changed from 30-minute demand windows to 15-minute after solar installation, resulting in 20-30% higher demand readings. File a complaint with the Georgia PSC immediately. This kind of bait-and-switch undermines the economics of solar and may violate the utility's tariffs.
The other thing to watch for is whether they're measuring net demand or gross demand. Net demand (actual draw from grid) is fair, but some utilities try to charge demand based on gross consumption ignoring solar offset. That's double-dipping since they're already getting the solar generation at reduced credit rates.
David, great question - I need to verify if it's net or gross demand measurement. The bills aren't clear on this. I'm preparing a formal complaint to the Georgia PSC citing improper rate schedule change without notice and demanding they provide 12 months of detailed interval data. Will also request they justify the measurement methodology change if that's what happened.
Eleanor, make sure to calculate the financial impact of the unauthorized rate change. If the customer would have made a different decision about solar installation based on accurate rate information, that's grounds for damages. Georgia Power should reimburse the difference plus interest going back to the interconnection date.
Document everything and keep pushing Eleanor. Utilities count on customers not understanding these technical details and just paying the higher bills. Similar case here in Harrisburg with PPL - took 8 months but we got the customer moved back to the correct residential rate and received $800+ refund. The PSC complaint was key to getting their attention.