Renewable hydrogen production. The role of Solar Thermal Water Splitting

Abstract

In a context of environmental crisis and depletion of conventional energy resources, the current energy model based on fossil fuels is obsolete and needs to be redefined and redesigned. Hydrogen economy can represent a good alternative. To get it, developing carbon-free renewable hydrogen production processes will be crucial. This Master Thesis is focused on the ones using solar thermal energy to split water. At first, world’s energy situation is analyzed to introduce the need of alternatives like hydrogen. Then, main hydrogen production processes are classified and discussed. Nowadays 96% of hydrogen production is based on decarbonizing fossil fuels. Even though, there are different renewable alternatives developed or under developing, which are expected to take a main role in the middle and long term. Among them, thermochemical cycles are a good solution to split water using solar thermal energy, especially two-step cycles like ZnO/Zn. Taking this one as an example, viability of a large-scale hydrogen production implementation using thermochemical cycles is analyzed at different levels: solar technology, energetic efficiency and economical status and perspective. I conclude that this process is viable nowadays, except for the economical level. It requires financial support in the first states of its commercial development, but not necessarily in its middle and long term. In those, could represent a great pathway to produce carbon-free renewable hydrogen