Japanese deep-tech firm Tsubame BHB has been selected by the Tokyo Metropolitan Government to produce nitrogen fertilizers from green hydrogen generated within the city, advancing a decentralized model for low-carbon ammonia synthesis.
Under the agreement, green hydrogen produced at Tokyo's renewable-powered facility in Keihinjima, Ota Ward, will be supplied to Tsubame BHB's pilot plant for ammonia synthesis. Working with partner companies, the firm will then use that ammonia as feedstock for the trial production of nitrogen-based fertilizers. The project forms part of Tokyo's "produce, transport, use" hydrogen strategy aimed at building a decarbonized economy.
Conventional ammonia production relies on grey hydrogen derived from natural gas, making the switch to green hydrogen a critical lever for cutting the carbon intensity of the ammonia and fertilizer industries.
What is Tsubame BHB's technology?
Founded in 2017, Tsubame BHB builds on-site ammonia production systems using decentralized plants powered by a proprietary low-temperature, low-pressure synthesis process. The technology rests on an electride catalyst developed by Honorary Professor Hideo Hosono of the Institute of Science Tokyo, formerly the Tokyo Institute of Technology. The approach contrasts with the high-temperature, high-pressure Haber-Bosch process that dominates global ammonia output and is typically viable only at very large scale.
The commercial logic is distributed production: smaller plants sited close to demand, sidestepping the freight and storage costs that burden a globally traded commodity. Tsubame BHB has already secured orders for two units in Japan and says it is in discussions for deployments across Global South markets, including Brazil, India and Africa, regions where import dependence and logistics costs weigh most heavily on fertilizer affordability.
The Tokyo pilot will serve as a proof point for whether city-scale green hydrogen can feed economically viable fertilizer production. Source green hydrogen output from the Keihinjima facility, scheduled to open in October 2025, will determine the pace of the trials.
