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The hydrogen economy is seeking its killer application, which can break down the ‘chicken and egg problem’, i.e., no hydrogen powered car can be sold if it cannot be refuelled, and nobody will invest to a hydrogen refuelling station if no one has a hydrogen powered vehicle. The applications like material handling, backup-power, and small stationary combined heat and power (CHP) engines are the most promising candidates, which may show financial return in 3-5 years. The replacement of fossil fuel with hydrogen in the automotive industry offers a substantial reduction of the harmful environmental effects, however, it is still the most challenging because of the absence of the hydrogen infrastructure, the price and the lifetime of the fuel cell (FC) engine and the unsuitable regulations, as well. In this work a new possible market was identified and analysed in different points of view. This market segment is a car-sharing system operating with small urban vehicles, which not only can solve some environmental problems (e.g., air pollution and CO₂ emission), but helps to reduce congestion, secure energy supply and ease its distribution. First, a sensitivity analysis was done and the key performance indicators of the system were determined. Finally, a possible hydrogen-based car-sharing service was designed and optimized to the downtown of Budapest, Hungary. A sustainable system was proposed, which can satisfy the needs of the business (i.e., profitability) and the environment.

In this work the technical and economic opportunities of a hydrogen fuel cell based urban mini-car fleet has been analysed for urban car-sharing application by different parameters like

• the fleet size,
• the rating power of the fuel cell,
• the cost of the vehicle
• the cost of the energy and the hydrogen

Two different operating strategies have been taken into account:

• hydrogen comes from regular supply at public hydrogen stations
• hydrogen is generated by electrolysis and all of the by-products are utilized (sold) like oxygen and heat.

It was surveyed, whether potential users were willing to pay more for a zero emission traffic service. It was come out that more than 50% of the respondents favored the idea and would pay a slightly higher price. The final price of 1 hour usage was set to $8.75, which is only a bit higher than a normal car sharing service fee. The calculation showed positive return. The sensitivity analysis showed that the key performance indicators were the utilization of the fleet, namely the sold hours/24 hours and the price of the by-products like oxygen and heat. As it was expected, the increase of the utilization of the fleet decreases the day of return (DoR), i.e., shows better financial conditions. The variation of oxygen price was more interesting. Below 2.5 USD/m³ a smaller rated power fuel cell size showed shorter DoR, while if oxygen could be sold at higher price the application of a bigger fuel cell was preferable. The effect of the cell size was different in the two operating conditions. If the hydrogen is bought from regular supply, the increase of the cell size increases the DoR linearly, however in the case of the on-site electrolysis the DoR levelled off by the increasing cell size. It was also clear from the figures that the effect of the cost of the energy or the hydrogen is insignificant in the case where a smaller cell was applied. The price of the vehicle (without the powertrain) became insignificant if the utilization exceeded 50%. The economies of scale were reached at 50 cars fleet. The application of different hydrogen storage technologies, i.e. metal hydrate and high pressure canister, which requires low and high pressure refuelling station, respectively, did not showed big differences. However, the specific investment cost of refuelling station was substantially lower in the case of low pressure technology, the longer refuelling time required more station and the lower maximal utilization reduced the utilization. It can be concluded that all of the examined cars are perfect for an urban car-sharing system and can be used for profitable services. In the beginning the application of smaller cells is more favourable, but if the utilization exceeds a critical value (30% in our case) bigger cars with bigger cells might be also profitable.