Wednesday, 28 November 2012

Using more electricity

Another record electricity bill came through. 9,000 yen. Almost 2,000 yen higher than any bill since last February. Deja vu. And we haven't put the heating on yet. Once again, this inspires me to look through the numbers and work out exactly what they are charging us for. The electricity bill doesn't say what the rate per kWh is, which I eventually found on the electricity company's website. 

Day time: 31.43 yen/kWh
At-home time: 21.23 yen/kWh
Night time: 9.33 yen/kWh

Then there is a fuel surcharge. This started the year at 1.3 yen/kWh and crept up to 1.8 in August, then dropped a little. It's going to be 1.64 in December. How careless of the electricity company to forget about the cost of fuel when deciding their tariff. I blame the airline companies for this practice, and I'm worried how far it will go. Perhaps the next time I go to the cinema they will charge extra for the film, or the next time I buy a carton of milk they will charge me extra for the milk.

Even so, this only makes at most  700 yen of the bill, and the difference between the higher rate and the lower rate is a less than 200 yen. 

Then there is a solar surcharge, which lets the electricity companies pass on the burden of paying people like me with solar panels for our electricity. This is only a tenth of a yen. 

Since August, they've added a renewable energy generation surcharge. Not sure why they need to do this as well as the solar surcharge. I thought solar was renewable, at least in the long-range future, if not aeonic future. This similarly makes a difference of tens of yen. Writing this paragraph probably cost me considerably more.

So we're no nearer explaining the 2,000 yen hike and it must be down to consumption. I can't compare with the previous year yet, but compared with the previous few months, the at-home consumption went up about 150 watts, night time 300 watts. That's a 40% an 45% increase.

Part of the reason is probably the humidifier, which I'll go into more later. We got a cheap humidifier at a second hand shop in preparation for the dry winter. If that accounts for the 150 watts at-home time, and some of the night time increase, then it was an expensive bargain!

I don't know if we're using more hot water, but heat pumps are less efficient at lower temperatures, so the drop in night time temperatures may account for the higher usage of night time electricity.