We tend to think of hydrogen as a type of energy storage, a carrier of energy. Hydrogen must be produced using another type of energy, and then the hydrogen can be used as fuel, for example, in cars. 

If the hydrogen is produced with renewable energy, you can simulate its use in En-ROADS in the advanced settings for Renewable Energy (click the 3 dots next to the Renewable Energy slider), and scroll down to find the slider for “Storage R&D breakthrough cost reduction.”

To test deployment of hydrogen in transportation, you could roughly approximate it by adjusting the breakthrough cost reduction in storage slider under Renewables, as well as the Transport Electrification slider (even though the energy carrier would be hydrogen rather than an electric battery in reality).