Techno-economic analysis of photoelectrochemical hydrogen production processes

Abstract

These days hydrogen (H2) is seen as a possible way to solve the world`s energy crisis. Within the last decades the photoelectrochemical hydrogen production has gained a rising attention. It is seen as a promising hydrogen production technology, producing hydrogen by the usage of a bias voltage and at least one semiconductor immersed in an electrolyte, used as an electrode. In this work, a techno-economic analysis has been done, focusing on three different photoelectrochemical hydrogen production processes. All considered processes work with photoelectrochemical cells, which are directly combined to a photovoltaic cell (PEC-PV device). A hydrogen refuelling cell, producing 400kg of hydrogen per day, an industrial process with a daily production rate of 4000kg hydrogen and a single home application with 1kg of produced hydrogen a day are considered. Two locations, Seville in Spain and Negev in Israel, are chosen. First the sizes of all components have been determined, using process simulation results of the mass- and energy-streams. With this the total capital investment, the operation and maintenance costs, the present value and the hydrogen production costs have been determined. Generally the costs in Negev are slightly lower and the higher the hydrogen production rates are, the higher are the total costs, but the lower are the hydrogen production costs. Depending on the process and the chosen location the total capital investment varies from 371.1k€ to 162.3M€, the annual operation and maintenance costs from 23.4k€ to 12.4M€, resulting in a present value from 670.8k€ to 321.4M€ and hydrogen production costs from 16.47€/kg H2 to 144.52€/kg H2. It is obvious, that the single home application is not economically feasible with its high hydrogen production costs. Comparing the other processes (16.47€/kg H2 to 22.12€/kg H2) with other renewable hydrogen production processes (3.57€/kg H2 to 10.75€/kg H2) they are neither economically competitive. Even by doing sensitivity studies by varying major influencing factors (e.g. insurance, maintenance, PEC-PV unit price and efficiency) they are not and might be even more expensive, if any made assumptions have been made wrong. However, the PEC-PV unit price is still unknown. If it lies under 100€/m2 combined with a higher efficiency of the PEC-PV unit (>8%) it is still likely, that any progress in semiconductor technology might make the technology economic worthy for middle and large production rates. Also concentration of the solar irradiation is sensible, as another study has predicted a significant decrease of costs by approximately 60%.