Densely-populated Japan has been a country with scarce energy resources, especially after the Fukushima Daiichi nuclear accident in 2011.
As a way to reduce the country's electricity usage, a growing number of people have started to generate their own electricity in recent years.
Among them, Fujii Tomoko, a woman who resides in the suburbs of Tokyo, has been living a net zero energy lifestyle. She hasn't had an electricity bill for five years.
Fujii's house has three solar panels installed on the balcony which generate more than one kilowatt per hour of electricity each sunny day, one-tenth of the average daily energy consumption of a typical Japanese household.
Apart from solar power, Fujii also generates electricity by riding a bicycle which has been linked to power generating equipment.
"After (the solar) energy is used up, I'll put my laptop on the handlebars and send an email while riding," said Fujii.
To save electricity, Fujii does not own a refrigerator, air conditioner or hot plate at home.
Instead, to store food, she fills a self-designed container with water which can naturally keep food cool. To lower the room temperature, Fujii hangs a bag on the shelf which drips water, and to cook, she uses a homemade solar-powered stove.
Now Fujii only uses very little electricity for lighting and for her washing machine which consume no more than one kilowatt per hour of electricity each day.
While a typical Japanese household pays a monthly utility bill around 4,000 yen (S$50), Fujii consumes less than one-tenth of the energy used by others.
"I take it as fun, to generate my own electricity and to live environmentally-friendly. It might bring inconveniences to my life, in some ways, but it depends on how we think of it. Why not take on the inconveniences as an interesting way to live your life?" said Fujii.
Fujji's net zero energy lifestyle has attracted a lot of attention. She has been invited to pitch her ideas on energy conservation to people across Japan and has even published a book on the topic.