All-electric homes may hobble electricity saving efforts

May 25, 2012

By JUNKI WATANABE/ Staff Writer

Without any of Japan's 50 nuclear reactors operating, and with expected power shortages this summer, it may be too late for utility companies that promoted fully electric households to put the genie back in the bottle.

Utilities have not come up with a plan for dealing with all-electric homes, which account for nearly 10 percent of all Japanese households.

As of March 31, a total of 4.85 million households in Japan, or 9.3 percent, were using electricity as their sole power source, according to an Asahi Shimbun survey of 10 electric power companies.

“It is too late to stop it now,” said a spokesperson for Kyushu Electric Power Co. “All we can do is put up with the situation.”

The percentages of fully electric houses are higher in the Hokuriku region and western Japan, where heating demands are relatively lower.

An “all-electric house” generally means a household using electricity as the source of heat for home appliances, cooking and the bathroom.

How much more electricity does a fully electric house consume, compared with a household using gas as its heat source?

According to a model case by each utility, a home using a heat-pump water heater with a high thermal efficiency consumes 2,500 kilowatts per hour more electricity a year. It is about 6,000 kilowatts per hour a year if a commonly used electric water heater is installed. Nationwide, all-electric homes consume a total of about 12 billion to 29 billion more kilowatts per hour usage annually.

That is equivalent to the power generated by two to four midsize nuclear reactors (with an output of 900,000 kilowatts per hour) annually.

Electric power companies started promoting the sales of water heaters for homes around 2000. They claimed the system is safer for older people because it does not utilize an open flame such as a pilot light on a gas stove.

The companies promoted sales with plans with reduced electricity rates for off-peak hours. Utilities also found it profitable to make use of nighttime electricity, when there is a surplus of energy, by selling it more cheaply to users.

That strategy worked well when the nuclear power plants were up and running, which were operating continuously for 24 hours.

Kyushu Electric Power Co., for example, reduces its nighttime consumption rate to half the normal rates.

In an effort to restrain daytime electricity consumption, Tokyo Electric Power Co. plans to offer lower rates for nighttime power consumption to households, starting in June.

However, utilities may pay the price for promoting the all-electric household system. They are suffering from higher fuel costs for thermal power generation to make up for the loss of nuclear power generation, as there is increasing demand for electricity, particularly from the all-electric systems it once promoted.

By JUNKI WATANABE/ Staff Writer
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