I'm working on a client analysis for Duquesne Light Schedule GS and getting confused between the demand charge tiers and energy block pricing. The tariff shows $18.50 per kW for first 50 kW then $15.20 above that, but then there's separate energy charges with declining blocks. How do these interact? - Claudia B.
Pennsylvania Rate Schedule GS confusion - demand charges vs energy blocks?
Claudia, those are two separate components that get added together on the bill. The demand charge ($18.50/$15.20) applies to the highest 15-minute peak during the month measured in kW. The energy charges are completely separate and apply to total kWh consumption in declining blocks. So if your client peaks at 75 kW and uses 8,500 kWh, you'd calculate: (50 kW × $18.50) + (25 kW × $15.20) for demand, plus the kWh blocks separately. Pennsylvania utilities love this dual structure. - Randy Dawson
Randy's exactly right. I see this confusion all the time with Ohio utilities too. Think of demand as the size of the pipe and energy as how much water flows through it. Completely separate charges that both show up on the bill. - Eugene W.
That makes perfect sense now! So I need to track both the monthly peak demand AND total energy usage separately. The Duquesne tariff book really could explain this better. Thanks Randy and Eugene! - Claudia B.