If I want to cut the amount of electricity I purchase from my neighborhood nuke plant (and I do), I should probably find out just how much I’m currently using, and when. That last part — when I use the electricity — is extremely important, for several reasons.
“On peak” electricity, when demand is greatest, is far more expensive than “off peak.” Here in Phoenix, we pay nearly 16¢ for each kWh used during the peak hours — weekdays between 9 AM and 9 PM. That makes sense. Air conditioners are running flat-out then and people are busy working (those who still have jobs) using computers, elevators, espresso machines.
Coffee? Hmmm. Be right back…. you can watch this way cool HD video in the meantime.
I’m back. Had to reheat a cup of coffee in the microwave. It took 40 watts to do it, too. (Remind me later to tell you about my new “Kill A Watt”™ device for measuring how much juice appliances use.)
Back to the second half of the equation: “off peak.” Instead of paying 16¢/kWh, we only pay 5¢/kWh at night and on weekends when demand is less. This difference becomes even more important when considering that solar energy is most abundant during the “on peak” hours. By installing solar panels, we’re hoping to eliminate our “on peak” nuke-power and only have to pay for the cheaper electricity at night.
Which brings us to … a chart. (Are you watching, Al Gore?)
Here’s our home energy use, showing off-peak, on-peak and total kWh for each billing cycle. The graph starts in the winter of 2008 and goes right through to the same period this year — March 2009.
It won’t come as a surprise to anyone who’s spent time in the Valley of the Sun that the total energy use is nearly three time higher in the summer compared to the winter. Sometime, I’ll have to put this chart up with an overlay showing temperatures. I suspect we’ll see a direct correlation.
Whew! That’ll have to do for now.
Oh, one last thing. See those gaps in the data, on the right side of the graph? That’s an artifact of APS’s billing cycles. The power usage for November 2008 got tossed into the December total. And the February 2009 got thrown into March. Which means that the actual usage was a lot lower in December and March than what shows up on the graph. Sorry about that.