The "Decarbonized Fuel" Imminent at Construction Sites in the Kanto Region -- From Honmachi 4-chome, 2025

The "Decarbonized Fuel" Imminent at Construction Sites in the Kanto Region -- From Honmachi 4-chome, 2025

In May 2025, several media outlets, including the Nihon Keizai Shimbun, announced the introduction of RD40, a new environmentally friendly fuel led by Taisei Corporation and Itochu Enex. This RD40 is a next-generation diesel alternative fuel that replaces conventional diesel fuel and emits less CO₂. The first practical introduction of this fuel was carried out in the "Honmachi 4-chome Project (tentative name)," located in a corner of central Tokyo, where both urban construction and environmental considerations were sought.

This "Honmachi 4-chome" is the name of an area that is considered one of the central business districts bordering Tokyo's Chuo and Chiyoda wards, where high-rise buildings and redevelopment projects are densely located. Here, RD40 is used as fuel for construction equipment used at the building site, and environmentally friendly construction activities are being verified on site.

This initiative, which also includes the spread of RD40 throughout the Kanto region, is in line with Japan's national goal of achieving carbon neutrality by 2050. The construction industry was no exception, especially as the government began to push concepts such as "decarbonization-first regions" and "green transformation (GX)" in the 2020s.

In addition to the rush to redevelop the 23 wards of Tokyo, the background to this trend is the formulation of the "Guidelines for Low Carbon Construction Equipment" by the Ministry of Land, Infrastructure, Transport and Tourism and the Ministry of Economy, Trade and Industry. Conventional construction equipment emits large amounts of CO₂, and because construction in urban areas requires consideration for nearby residents, quietness and emission reduction performance are becoming more important.

In this context, the adoption of the RD40 is a concrete step toward CO₂ reduction at construction sites and a symbolic demonstration toward building a zero-emission city. Moreover, the concept of expanding throughout the Kanto region has the potential to spread to other metropolitan areas and even regional core cities in the future.

In other words, the quiet construction site in Honmachi 4-chome may soon become the starting point for changes in construction sites nationwide, and the RD40 fuel is not just an energy resource, but a new symbol for "sustainable urban development.