According to Reuters, the local assembly in the Japanese capital passed a legislation mandating the installation of solar power panels on all new homes built by large-scale homebuilders after April 2025 in order to reduce household carbon emissions.

The mandate is the first of its type in Japan, and it mandates approximately 50 large builders to install renewable energy power sources, primarily solar panels, in residences up to 2,000 square meters (21,500 square feet) in size.

Only 4% of Tokyo’s buildings with rooftop solar panels are actually using them, Mayor Yuriko Koike said last week. The Metropolitan Government of Tokyo has set a goal to reduce GHG emissions by half from 2000 levels by the year 2030.

Japan is the world’s fifth largest carbon emitter and has pledged to become carbon neutral by 2050. However, this goal is unlikely to be met without significant changes, as the country has relied heavily on coal-burning thermal power since most of its nuclear reactors were shut down after the 2011 Fukushima disaster.

“In addition to the existing global climate crisis, we face an energy crisis with a prolonged Russia-Ukraine war,” Risako Narikiyo, a member of Koike’s regional party Tomin First no Kai, said at the assembly on Thursday. “There is no time to waste.”

Photo by Luke Paris on Unsplash