Last summer when the antinuclear movement was receiving a lot of media coverage, the government and utilities justified their plans for reopening nuclear power plants with statistics purportedly showing how dangerously close to capacity electricity usage is in the summer, when everyone has their air conditioners on. Thanks to energy conservation efforts on everyone's part there were no overloads, but in terms of households, reibo (cooling) only accounts for 2 percent of overall energy usage when measured in calories. Danbo (heating), on the other hand, accounts for 25 percent of home-energy usage.

Of course, there are various methods for heating homes in Japan. In addition to electricity, there is natural gas, liquid propane gas and kerosene (toyu), but electricity has been increasing in recent decades as a means for home-heating. Between 1980 and 2005, the use of kerosene, which is utilized in space-heating "stoves," declined from 71 to 45 percent in terms of heating needs in the Kanto area, while both natural gas and LPG increased from 21 to 35 percent and electricity from 8 to 20 percent. However, when you factor in all of a home's energy needs — cooking, lighting, bathing, etc. — electricity accounts for 50 percent, kerosene 17 percent, natural gas 20 percent and LPG 10 percent of household energy consumption. That was for all homes in Japan in 2009. In 1973, electricity only accounted for 28 percent of overall household energy usage. So with the promotion of all-electric houses in recent years, the overall portion of home heating by electricity has probably gone up even more.

The peak period for electricity usage in the wintertime is between 5 and 6 p.m., and during the current sharp cold spell, electricity usage as reported by Tokyo Electric Power has been over 90 percent during the peak time slot. The main difference between wintertime and summertime is that power plants reduce capacity in the winter, so 90 percent represents less power usage in the winter than it does in the summer. Most air conditioners run on electricity, but as shown above heating systems use a variety of methods, so electrical usage is deemed to be less. But since electricity usage in the winter is on the increase, why aren't power companies warning people to cut back when the usage gets close to the limit, as they did last summer?