I've been feeling like our power bills have been going through the roof recently, despite our usage not going up much. I happen to have both usage and billing data going back 20 years, so I thought I'd check. It turns out my gut feel was correct!
This is a graph of total monthly bill (for January and July each year from 2026) divided by the number of kWh used in that month. Back in 2006 we paid 15c per kWh; now it's 48c. (That's the total we pay, including all the fixed charges, not the marginal cost per kWh).
For contrast, if the bill had risen in line with CPI inflation, 15c would have turned into 25c, according to the RBNZ.
As an aside I have no idea what happened in July 2012. That spike is from a freak enormous bill with average usage - presumably a clerical error?
Not sure what, if anything, I can do with this information, but it's nice to know I'm not mistaken, at least!
