Japan is planning to build what could become the world’s largest floating wind farm – a gigawatt-scale project off the Izu Islands to power the island chain and Tokyo.

But the plan, championed by Governor Yuriko Koike, is facing questions over whether it can be delivered by 2035. There are also doubts about the power generation forecast and whether Japan could tackle the technical demands of such a megaproject.

Koike first announced the wind farm project at a climate change conference in Azerbaijan in 2024.

The plan calls for floating and tethered wind turbines to produce 1 gigawatt of power, equivalent to the capacity of a nuclear reactor, according to the government’s plans.

In comparison, the world’s largest operational floating wind farm, in Norway, generates 94.6 megawatts, according to analysts.

Tokyo intends to use floating turbines because they can have less impact on the marine environment during construction than units permanently anchored to the seabed. The plans call for electricity supplied from the turbines to the Izu Islands and Tokyo, around 160km to the north, via submarine transmission cables.