Process schemes and scenarios of solar hydrogen production via high temperature electrolysis

Kurzfassung

High temperature electrolysis is considered as a promising process for a sustainable hydrogen production. In the high temperature electrolyser, the decomposition of water steam into hydrogen and oxygen takes place. The requirements of the electrolyser are high-temperature heat and electricity, which can be supplied by the concentration of solar radiation. Different technologies, which make use of the principle of concentrating solar energy, are able to provide the electrolysis process with heat and electricity. The solar systems, which are considered in particular, are based on solar tower, parabolic dish and parabolic through technologies. The former uses many larges, computer-controlled, sun-tracking mirrors, so called heliostats to focus the incoming solar radiation into a receiver placed on the top of a tower. The solar tower technology has been demonstrated for many working fluids, e.g. air and molten salt. The heat of the working fluid is used to generate water steam, which runs a steam turbine in order to generate electricity. The second technology uses a parabolic concentrator, which concentrates the solar radiation into the thermal receiver integrated in the heat engine, which perform the conversion of heat to electricity. The last one uses mirror reflectors to concentrate sunlight onto thermally-efficient receiver tubes placed in the trough focal line in order to generate high temperature steam which can drive a turbine for electricity generation or be used directly for process heat. This paper will present an overview of the high temperature electrolysis coupled to the mentioned solar energy technologies, including process design.