Energy efficient gadgets in high demand in Japan
Japan is braced for a summer of electricity shortages after the earthquake and tsunami in March.
The country relied on nuclear power for 30% of its supply.
But the Fukushima plant was disabled by the disaster, and another nuclear plant at Hamaoka has been shut down because of safety fears.
Tokyo's electronics shops are busy these days with customers looking for energy efficient gadgets.
The earthquake has left Japan with an electricity shortage, so people have been urged to use it sparingly.
At Bic Camera, a huge multi-storey building in the Yurakucho district, demand began to pick up the week after the earthquake and tsunami.
The latest lines of eco-fridges are selling well.
Also popular is a new range of air conditioners, which can sense when people are in the room, and whether they are being active or sitting still, and adjust the cooling output accordingly.
The machines even send a message to the remote control to remind people to shut the doors and windows if they detect a draught of warm air.
"The interest level has risen quite a bit," says salesman Kai Fujiwara.
"If you are talking about [energy efficient] LED lights alone, it's twice as much as before the quake. LED lights are expensive, 20 or 40 times more than ordinary light bulbs, but people are buying 10 at a time."
Power consumption falls
The Japanese have a large appetite for power.
Tepco, which serves Tokyo and the surrounding area, used to boast it sold more electricity than was consumed in all of Italy.
But sales have fallen sharply along with this new enthusiasm for frugality.
Tepco produced, or bought from other utilities, 15.3% less electricity in April compared with the same month last year.
Tohoku Electric, which serves the badly hit north east, saw its capacity fall by 19.3%.
Sandals and T-shirts
More generating capacity should be online by the summer, but the shortfall in the east of Japan could still be 10% of normal supply.
Surplus power from the west cannot be transferred easily because electricity there runs on a different frequency.
In response the Cool Biz campaign, in which salarymen are urged to discard their jackets and ties every summer to save on air conditioning, has been ramped up.
Under the motto Super Cool Biz, the government is suggesting they consider sandals and T-shirts, even Hawaiian shirts, for the office this year so the thermostat can be set even higher.
But just saving electricity is not enough.
The way it is generated and supplied is also being reassessed.
Two days after the earthquake, the Kirin brewery at Yokohama began selling electricity to the national grid.
Gas-fired generators on site power the brewing, bottling and canning processes, and with spare machines installed in case of breakdown there is more capacity than needed.
Now they have been put to use, providing enough energy to run more than 3,000 homes.
Harnessing electricity from factories is likely to become increasingly important to Japan.
"I don't think any of us imagined we would lose the power supply because of a natural disaster like we did," says Junichi Nonaka, the Kirin brewery manager.
"So we have realised that we took unlimited electricity for granted. We also now know we need to save energy and not to waste it."
Even before the disaster, though, Japanese industry used energy efficiently.
Consumption is about the same as in the early 1970s, despite the economy now being far bigger.
Others are more wasteful.
Many shops are brightly lit and doors are typically left open in the summer, allowing cool air to stream onto the pavement.
Some 4% of electricity in households goes to power heated toilet seats, so clearly there is room for saving.
But getting by on less, or making more, will take innovation.
That could be an opportunity for the economy.
Solar panels are already being adopted, but some experts believe the technology could be a dead end.
Even if production can be ramped up, making each unit cheaper, it will still be a costly way of generating electricity.
Instead, some believe Japan's position on the Pacific ring of fire, the very thing that makes it vulnerable to earthquakes, may provide an answer.
"Japan is full of geothermal resources," says Taishi Sugiyama from the Central Research Institute of Electric Power Industry.
"There are many volcanoes.
"If we successfully develop that, then it can be one of our major electricity supplies.
"You have hot water everywhere in Japan. If we drill much deeper we can tap geothermal resources. The potential is close to 10% of Japanese power supply."
Mother of invention
Over the next few months Japanese offices and homes are likely to be rather uncomfortable with less air conditioning.
Tokyo's summer is sticky.
But necessity is the mother of invention.
And in the long term the drive to conserve power and find new sources could help Japan's economy to recover.