  Road vehicles play an important role in the UK's energy systems and are a
critical component in reducing the reliance on fossil fuels and mitigating
emissions. A dynamic model of vehicle fleet, based on predator-prey concepts,
is presented. It allows to predict the evolution of the hydrogen based
vehicle's role in the UK's vehicle fleet and the sensitivity of this growth to
the supply chain. In addition to this, this model is used to predict the demand
of hydrogen for the passenger vehicle fleet for various scenarios. A key result
is that the amount of hydrogen required to support a huge network of hydrogen
based vehicles is currently not practical, regarding the infrastructure
required and the cost to build such an infrastructure. In order to mitigate
that, the policy focus should move primarily from hydrogen based vehicles to
first encompass range extenders in the transport energy system.
