The article compares using hydrogen as fuel in electric vehicles in two ways: to power a battery electric vehicle or to run a fuel cell vehicle. They found that the fuel cell vehicle used 13% less hydrogen per kilometer compared to the battery electric vehicle when both were powered by hydrogen, making the fuel cell vehicle more efficient in terms of driving range. This study helps understand how hydrogen can be a cleaner and more efficient energy source for future vehicles, especially in reducing fossil fuel use in the transportation sector.