Fuel cell electric vehicles and hydrogen balancing 100 percent renewable and integrated national transportation and energy systems

Future national electricity, heating, cooling and transport systems need to reach zero emissions. Significant numbers of back-up power plants as well as large-scale energy storage capacity are required to guarantee the reliability of energy supply in 100 percent renewable energy systems. Electricity can be partially converted into hydrogen, which can be transported via pipelines, stored in large quantities in underground salt caverns to overcome seasonal effects and used as electricity storage or as a clean fuel for transport. The question addressed in this paper is how parked and grid-connected hydrogen-fueled Fuel Cell Electric Vehicles might balance 100 per cent renewable electricity, heating, cooling and transport systems at the national level in Denmark, Germany, Great Britain, France and Spain? Five national electricity, heating, cooling and transport systems are modeled for the year 2050 for the five countries, assuming only 50 percent of the passenger cars to be grid-connected Fuel Cell Electric Vehicles, the remaining Battery Electric Vehicles. The grid-connected Fuel Cell Electric Vehicle fleet can always balance the energy systems and their usage is low, having load factors of 2.1-5.5 percent, corresponding to an average use of 190-480 h per car, per year. At peak times, occurring only a few hours per year, 26 to 43 percent of the grid-connected Fuel Cell Electric Vehicle are required and in particular for energy systems with high shares of solar energy, such as Spain, balancing by grid-connected Fuel Cell Electric Vehicles is mainly required during the night, which matches favorably with driving usage.