Hydrogen Storage Volume Assessment and Uncertainty Quantification Utilizing Random Forest Ensemble Learning
Authors: Katterbauer Klemens , Shehri Abdallah Al , Qasim Abdulaziz , Yousef Ali 
Published: October 2023

Hydrogen has been shown to be an essential potential energy carrier with some significant opportunities to reduce carbon emissions related to power generation and provide an alternative for power generation for several applications. Hydrogen is abundant as an element in our Earth and is widely used in the form of water and other substances as a composite[BAM1] (Turner 2004, Dawood, Anda and Shafiullah 2020). There can be various uses for hydrogen, such as fuel cells and a by-product for water. This enables it to be clean fuel in terms of carbon emissions. Hydrogen can be obtained from many resources, such as natural gas and nuclear power. Furthermore, biomass and renewable power incorporating solar and wind are additional alternatives. Given that these sources differ but all enable hydrogen to be produced, this makes it an attractive alternative for fueling both transportation and producing electricity (Katterbauer, Marsala, et al. 2021, Al Shehri and Shewoil 2020). There are various techniques to generate hydrogen and include different processes. These are thermal processes and electrolytic processes, in addition to processes based on solar and biological processes.

When it comes to biological processes, these revolve around utilizing microbes for producing hydrogen via biological reactions (Sivaramakrishnan, et al. 2021, Katterbauer, Qasim, et al. 2021). The microbes may incorporate both bacteria and microalgae. The process may be either in the form of a microbial biomass conversion or a photobiological process. In the microbial biomass conversion, the microbes break down the organic matter. In the case of a photobiological process, sunlight is used to generate the hydrogen. The organic matter can be in the form of wastewater but also utilize biomass. Microbial biomass conversion is promising as it enables the utilization of the fermentation process to break down organic matter. This breakdown enables produce of hydrogen subsequently. Various materials, such as sugars, raw biomass source, and wastewater may form the biomass material. For the direct hydrogen fermentation process, the hydrogen is produced directly via the microbes (Balachandar, et al. 2020). There are several challenges that may slow the fermentation process. The limited yield may arise because of this slower-than-expected fermentation. New initiatives such as microbial electrolysis cells enable harnessing of energy produced by microbes from hydrogen and electricity. The challenge is the efficiency of the processes that are limited in scope. This limits the amount of hydrogen to be produced efficiently (Katterbauer, Hoteit and Sun, A Time Domain Update Method for Reservoir History Matching of Electromagnetic Data 2014a, Katterbauer, Hoteit and Sun, EMSE: Synergizing EM and seismic data attributes for enhanced forecasts of reservoirs 2014b, Katterbauer, Hoteit and Sun, History Matching of Electromagnetically Heated Reservoirs Incorporating Full-Wavefield Seismic and Electromagnetic Imaging 2015).

Solar-reliant processes are based on photobiological, photoelectrochemical, and solar thermochemical processes. Photobiological processes take into account the natural photosynthetic activity of bacteria to create the hydrogen from these natural matters. Photoelectrochemical processes have a different method and utilize semiconductors to separate water into hydrogen and oxygen. This enables subsequent extraction of the hydrogen (Pourrahmani and Moghimi 2019, Katterbauer, Hoteit and Sun, Synergizing Crosswell Seismic and Electromagnetic Techniques for Enhancing Reservoir Characterization 2016).