Working on an Eversource Connecticut bill analysis and I'm getting confused by their voltage discount methodology. Schedule G-2 shows different discount factors for 4.16kV versus 13.2kV delivery. The tariff language talks about "distribution voltage level adjustments" but the math doesn't seem to match what's on the actual bills.
Eversource CT voltage discount calculation question
Vince - Eversource uses a tiered voltage discount system. Primary service at 4kV class gets about $0.75/kW demand credit, while 13kV class gets $1.25/kW. The energy charge adjustments are separate - usually 2-3% reduction from secondary rates. Are you seeing different numbers on your client's bills?
Derek - the demand charge discount matches what you're saying, but the energy adjustment seems inconsistent. Some months show 2.1% discount, others show 2.8%. There's a line item called "Voltage Adj Factor" that varies monthly. I'm wondering if it's tied to system losses or load factors.
Vince - I've seen similar variations with TVA here in Tennessee. The voltage adjustment factors sometimes get updated seasonally based on system loss studies. Check if Eversource files annual loss factors with the Connecticut PURA - that might explain the monthly variations you're seeing.
Terry's right about the loss factors. Ohio Edison updates their voltage adjustments quarterly based on distribution loss studies. The percentage can vary from 1.8% to 3.2% depending on seasonal loading patterns. It's usually higher in summer when distribution losses are greater due to higher loads.
That makes sense Jim. I found Eversource's 2011 loss factor filing with PURA - they update the factors in March and September each year. Summer factors are higher because of increased air conditioning load and higher I²R losses in the distribution system. The math finally adds up now.
Vince - good detective work on finding the loss factor filings. In Texas, ERCOT publishes system-wide loss factors monthly, but the individual utility adjustments can still vary. It's one of those details that can significantly impact savings calculations if you don't account for the seasonal variations.
This is why I always request 24 months of billing history when analyzing primary service opportunities. The voltage discounts can vary significantly throughout the year, and you need a full cycle to accurately calculate the financial benefits. Georgia Power's adjustments range from 1.9% to 3.4% depending on the season.
Derek H - exactly right about the 24-month analysis. I made the mistake early in my career of calculating payback based on just one or two bills. The seasonal variations can change your ROI calculation by 20-30%. Always use annual averages when evaluating primary service conversions.
Frank's advice is spot on. LG&E here in Louisville has similar seasonal adjustments. Their voltage discount ranges from 2.2% in winter to 3.1% in summer on energy charges. The demand charge discount stays constant at $0.95/kW year-round, but the energy savings definitely fluctuate with system losses.
Jack - LG&E's approach is pretty standard. Duquesne Light uses a similar methodology with quarterly updates. The key is understanding that distribution losses are higher during peak demand periods when transformers and conductors are loaded heavily. That's why summer voltage discounts are typically larger.
This has been really helpful for understanding the technical side. From an audit perspective, I always verify that the utility is applying the correct voltage adjustment factors for each month. I've found billing errors where they used the wrong seasonal factor, which can cost customers hundreds or thousands of dollars annually.
Rachel - good point about billing errors. I've seen cases where the voltage adjustment gets stuck on one factor and doesn't update seasonally. Always worth double-checking that the factors match what's filed with the regulatory commission. Eversource had a systematic error in 2009 that affected about 200 primary service customers.
Vince - I remember that Eversource issue. It took them six months to identify and correct the billing system error. Customers got retroactive credits, but some facilities lost tens of thousands in savings during that period. That's why it's important to monitor these adjustments regularly, not just during the initial audit.