Just got slammed with a $3,400 demand charge on our July bill from NV Energy. Client has a 150-ton chiller that tripped offline during a brief power flicker, then restarted automatically about 20 minutes later. The startup surge hit 485 kW for about 8 minutes while the system came back online. We're on Schedule MGS with a $23.50/kW demand rate. Has anyone dealt with NV Energy on getting relief for equipment malfunction spikes like this? The client is furious and wants to know why their demand control system didn't prevent this.
NV Energy demand spike from chiller startup - $3,400 hit!
Tony, that's brutal but unfortunately pretty typical. NV Energy is notoriously strict on demand charges regardless of cause. You might have better luck if you can document that this was due to a utility-side power quality issue that caused the equipment malfunction. Did you get any power quality data from the event? Also check if the client has any demand limiting controls that should have prevented multiple large loads from starting simultaneously. Sometimes the demand control system itself needs adjustment after an event like this.
Had a similar situation with MLGW here in Memphis last year. 200-ton chiller startup after a weekend shutdown created a 520 kW spike that cost the client $4,200 extra. MLGW wouldn't budge on the charge, but we did get the client to install soft-start controls and upgrade their demand management system. The key is proving to the utility that you're taking steps to prevent future occurrences. Sometimes they'll work with you on a payment plan if nothing else.
Jorge here from San Antonio - CPS Energy has a "power quality exception" clause in their large commercial tariffs that might apply. You need to file within 30 days of the bill date with documentation showing the spike was caused by utility power issues. Not sure if NV Energy has something similar, but worth checking their tariff language. We've had success with this approach about 40% of the time when we can prove utility fault.
Thanks everyone. I've got the power quality data from our monitoring equipment - shows a 0.3 second voltage sag to 87% just before the chiller tripped. That should be enough to demonstrate utility-side issues. Jorge, I'll dig into the NV Energy tariff for any similar exception language. Randy, the demand control system was supposed to prevent this but apparently has a 15-minute reset delay that didn't account for the chiller's 20-minute restart cycle. We're recommending they reprogram it to 25 minutes minimum.
Leslie from Buffalo here - had good luck with National Grid using the "extraordinary circumstances" provision when we had multiple RTUs restart after a brief outage. The key was detailed documentation including time-stamped power quality data and equipment logs. Also helped that we could show the client's normal demand profile versus the anomaly. File a formal dispute with all your documentation within 30 days, don't just call customer service.
Brett here from Kansas - Evergy has been more flexible lately on equipment malfunction spikes, especially if you can show it was utility-caused. Document everything: voltage sags, equipment restart sequences, normal vs. abnormal demand patterns. Also consider having the client install sequence controls to prevent simultaneous large load startups. Prevention is cheaper than paying these demand charges repeatedly.
Update everyone on best practices: always install power quality monitoring on large commercial accounts, especially those with critical HVAC equipment. The data is invaluable for these disputes. Also recommend clients review their maintenance schedules - a lot of these "malfunction" spikes happen because equipment hasn't been properly serviced and is more susceptible to power quality issues.
Great advice Randy. Filed the formal dispute with NV Energy today including all power quality data and equipment logs. Also got a letter from the HVAC contractor confirming the equipment was operating normally before the voltage sag event. Will keep everyone posted on the outcome. Client is also moving forward with soft-start controls and demand management system upgrades to prevent future issues.