"Hydrogen" is used at the Tokyo 2020 Olympics in many ways.

First of all, the fuel of the torch. Hydrogen is the fuel for some of the torches used in the torch relay and the flame that lights the torch stand. Hydrogen is originally colorless and transparent in burning, so is mixed with "baking soda (sodium bicarbonate)" to give flame color. It's a flame reaction.

Hydrogen is also used in the electricity in the Olympic Village. During the Olympic Games, the electricity is supplied by the renewable energy to 49 facilities such as the Olympic Stadium. And hydrogen is brought from "Fukushima Hydrogen Energy Research Field (FH2R)" in Fukushima Prefecture, and used at some of the accommodation buildings and rest facilities for athletes.

There are also fuel cell vehicles used as vehicles for official cars, and about 70 fuel cell buses run in Tokyo. In addition, there are 22 hydrogen refueling stations in Tokyo (of which 5 are bus-compatible stations, I suppose).

I'm glad that "hydrogen" is playing an active part with Athletes :D