Photo/Illutration Solar panels are set up on a facility within the Ueno Zoological Gardens in Tokyo. (Provided by the Tokyo metropolitan government)

Tokyo will oblige homebuilders to outfit their newly built homes and buildings with solar panels starting in April 2025.

A legislative measure to introduce quotas for solar panel installations will be submitted to the metropolitan assembly in December this year, according to a Sept. 9 announcement by the Tokyo metropolitan government.

But it will not come with penalties to enforce the new requirements.

Still, the change would make Tokyo the first place in Japan to require new homes to come with solar panels installed. Similar frameworks have already been put in place in Kyoto and Gunma prefectures, but they do not cover detached houses.

“We will be nurturing a movement so that power will be generated on rooftops as naturally as houses have roofs,” Tokyo Governor Yuriko Koike said at a Sept. 9 news conference.

If the reform effort goes smoothly in the capital, the central government may follow in Tokyo’s footsteps.

The move is being made to counter the recent trend of rising emissions from households. Tokyo is looking to halve greenhouse gas emissions by 2030 from their 2000 levels. About 30 percent of its carbon footprint comes from households alone.

The central government set a goal last fall to have solar panels installed on a greater number of newly built residences. Yet it has refrained from making it compulsory.

Under Tokyo’s plan, owners who commission the construction of large buildings with a total floor space of 2,000 square meters or greater would have to outfit them with solar panels.

Housing providers and building developers are supposed to install them on homes and other small and midsize structures. Some 50 major corporations that meet certain requirements, such as those that offer a total floor space of at least 20,000 square meters per year, are expected to fall into this category.

The metropolitan government aims to make the program more feasible by giving homebuilders a fair amount of discretion in the process, and by having them take responsibility for introducing the solar panels while homeowners can decide whether to use or sell the electricity.

Homebuilders will be able to decide how many solar panels they will install, based on how many homes they construct along with their locations. The companies will be able to freely select which properties to equip with solar panels, so long as they meet their targets.

Even if contractors and developers miss their targets, they would not face penalties.

Tokyo will instead urge corporations to stick to their goals through offering guidance and publishing their names. In other words, it will name and shame any laggards.

Adding solar panels to a rooftop is estimated to cost about 1 million yen ($6,900).

Since that expense will likely be added to the price of the house, Tokyo will provide subsidies for home buyers and solar panel rental agents to reduce the burden on consumers.

According to Tokyo’s estimates, as many as 25,000 new buildings a year, mostly private homes, will have to install these solar panels under the new framework.

The metropolitan government is planning to step up the pace of decarbonizing residences by improving their heat-blocking and energy-saving abilities, and by making it mandatory to install charging stations for electric cars in new residences.

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