Our sawmill in Missoula got hit with a $7,200 power factor penalty from NorthWestern Energy for February usage. We're on Schedule LGS and they're claiming our PF dropped to 0.72 during several peak periods. The thing is, our correction equipment was functioning normally according to our monitoring system. I'm wondering if the extreme cold weather we had (-30F for a week) affected either our equipment or their meter readings. Has anyone dealt with PF measurement issues in extreme cold?
NorthWestern Energy PF penalty dispute - need advice
Noel, extreme cold can definitely affect capacitor performance. Capacitors lose capacity when temperatures drop, and if your banks are installed outdoors without proper temperature compensation, you could see reduced correction during cold snaps. Also check if any of your capacitor units fused out during the cold spell - we've had that happen with older equipment.
Cindy's right about cold weather effects. We service correction equipment throughout eastern Washington and see this regularly. Oil-filled capacitors can lose 10-15% of their rating when temperatures hit -20F or below. If your system was sized for normal conditions, extreme cold could push you below the utility's PF threshold. Did NorthWestern provide specific dates and times for the violations?
Ernest, yes they provided the interval data. The worst readings were during the coldest three days in February, which supports your cold weather theory. Our capacitor banks are outdoor-mounted and about 8 years old. I'm wondering if we should dispute the penalty based on equipment performance being affected by extreme weather conditions beyond our control.
In Virginia, Dominion Energy has provisions for weather-related power quality issues, but you have to demonstrate equipment malfunction due to conditions outside normal operating parameters. Montana might have similar protections under PSC rules. Worth checking the tariff language for force majeure or equipment failure clauses.
Before disputing, I'd recommend having a qualified electrician test your capacitor banks. If they're operating below nameplate due to age or cold damage, you've got documentation for the dispute. Duke Energy in Ohio accepted our weather-related PF variance when we could prove equipment degradation from extreme conditions.
Chuck makes a good point about testing. We had Entergy waive a PF penalty when we proved our correction equipment failed during an ice storm. The key is showing the utility that you maintain your equipment properly and the violation was due to extraordinary circumstances, not neglect.
Noel, I've dealt with cold weather PF issues in Memphis, though not as extreme as Montana winters. The key documentation you need is: 1) Proof your equipment was properly maintained, 2) Weather data showing abnormal conditions, 3) Capacitor test results showing degraded performance, and 4) Your normal PF compliance history. Montana PSC Rule 38.5.2208 covers power quality disputes - worth reviewing before filing your complaint.
Thanks Randy, that's exactly what I needed. I'll pull together the documentation you mentioned and review that PSC rule. Our electrician is scheduled to test the capacitor banks next week. If they show reduced capacity due to cold damage, I'll file a formal dispute with both NorthWestern and the PSC.
Noel, when your electrician tests the caps, make sure they check the oil condition too if they're oil-filled units. Cold cycling can cause moisture infiltration and dielectric breakdown. That kind of damage would definitely support your case that the penalty was due to equipment failure from extreme weather.
UPDATE: Had the caps tested and two units in our main bank tested at 70% of nameplate capacity. Moisture contamination in the oil from freeze-thaw cycles. Filed dispute with NorthWestern yesterday with full documentation. Electrician says replacement units will be temperature-compensated to prevent future issues.
Great work putting together that documentation, Noel. Equipment failure due to extreme weather is a legitimate defense, especially when you can prove proper maintenance and show the abnormal conditions. Keep us posted on how NorthWestern responds to your dispute. This case could help other members facing similar cold weather PF issues.