Saturday, September 4, 2010

Fighting With The Power Company

 I'm near Phoenix Arizona, USA and my power company is APS.  They have "Demand" billing which means they measure your usage of power and take your peak usage for a month and add a surcharge for delivering that much power.....regardless of how long you actually use it.  So for example: you have the dryer running and the A/C kicks on, that's 1400 Watts for the toaster and 2000 for the dryer you just hit 3.4 kW for a two minute run of the toaster.  During the summer at a demand charge of $13.404 per kW plus a "Generation Charge" $7.114 per kW plus a "Delivery Charge" of 2.089 per kW you just hit over $60 for less than 10 cents of electricity.

Yes, you're reading it right.  They charge separately for Usage (kWh), Generation (kW) and Delivery (kW), and the kW items above are billed based on the single largest use of power during peak periods anytime during the month.  So at any point during the peak periods someone can mistakenly turn something on and WHAM, you've got a monster power bill and you don't even suspect it.  All the compact fluorescent bulbs in the world can't make up for one mistake with a water heater, or heaven forbid, an A/C compressor or welder.

To add insult to injury, they have the following definition of "Demand" on their web site:
This component is part of the pricing for the Combined Advantage plans. "Demand" or kW is the average kW used during the 60-minute period of maximum use during the on-peak hours of the billing month. The kW used is determined from readings of your APS meter. 
This implies that they average the usage over an hour and you get billed for the highest hour of the month.

This is simply not true.  I discovered the definition was wrong when I finished the system to measure power usage in real time.  I never had an hour where I exceeded 2.4 kW and those periods were for a very short time, far less than an hour.  However, when I got the bill they listed 2.2 kW as the demand.  I called and asked why and they told me it was what the meter recorded.  The meter reading is God.

So, I talked to the customer support people several times, the metering people several times, the meter manufacturer a couple of times and finally got an extensive manual on the meter itself.  Armed with this I asked to talk to an engineer that understood their metering.  Guess what?  I actually got a call back!!

Even stranger, the engineer agreed with me.  The definition on their web site was clearly wrong and they don't do any averaging; they take the highest demand and hold it over a month.  I get billed for any mistake I make in power usage.  The engineer agreed to discuss this definition with others and get a correct definition in place.

This was back on 8/24/2010.  Still waiting, we'll see.


  1. I'm just starting to read your blog from the beginning, so forgive me if you might have updated this in a future posting. First of all, are you really talking about 13.404 DOLLARS per kW or did you actually mean CENTS? I'm not familiar with energy pricing in the States at the moment, but here in Germany one Kilowatt costs a just under 30 Eurocents in average (which at the current exchange rate correlates to about 35 US-cents). So your would be paying more than 65-times as much as we do here in Germany. I've lived in New Mexico for a few years and don't remember prices being that high.

    And second: Did you ever get a call back about their price-measuring habits?

    Greets,Beejay (A fellow energy measuring, home automating tinkerer from Germany)

    1. This comment has been removed by the author.

    2. I was fooled for a minute on this and almost agreed that it was a mistake, however it's correct (for the time, it's even more now). See, this is not a normal usage charge where they charge you for the kW you use, this is a special charge for using a lot during the peak period.

      They measure the max usage over an hour and charge me a ton for that one hour of high usage regardless of my overall usage. It's only an one hour out of the month, but you can see what the result is on a monthly bill.

      They still do this, but I've managed to keep the 'demand' number low for the last few years and don't have to worry much about it. I did it through monitoring the power usage constantly and adjusting my use of appliances to keep that 'demand' number down as low as is reasonable.

    3. Oh, about getting a reply: Yes I did eventually get some closure on this irritation. They replaced my meter and things settled down to a more reasonable level. I have that interaction posted somewhere on this blog.