With regards to weight - hydrogen tanks are heavy, even if the fuel is light. The tanks on a Toyota Mirai weight 87.5kg (193 lbs). In addition you need the fuel

With regards to weight - hydrogen tanks are heavy, even if the fuel is light. The tanks on a Toyota Mirai weight 87.5kg (193 lbs). In addition you need the fuel cell, piping, more wiring.. The actual weight advantage is not as great as it might seem.