Lebanon

In the context of hydrogen production from biomass or organic waste with dark fermentation this study analysed 55 studies (339 experiments) in the literature looking for the effect of operating parameters on the process performance of dark fermentation. The effect of substrate concentration pH temperature and residence time on hydrogen yield productivity and content in the biogas was analysed. In addition a linear regression model was developed to also account for the effect of nature and pretreatment of the substrate inhibition of methanogenesis and continuous or batch operating mode. The analysis showed that the hydrogen yield was mainly affected by pH and residence time with the highest yields obtained for low pH and short residence time. High hydrogen productivity was favoured by high feed concentration short residence time and low pH. More modest was the effect on the hydrogen content. The mean values of hydrogen yield productivity and content were respectively 6.49% COD COD−1 135 mg L−1 d −1 51% v/v while 10% of the considered experiments obtained yield productivity and content of or higher than 15.55% COD COD−1 305.16 mg L−1 d −1 64% v/v. Overall this study provides insight into how to select the optimum operating conditions to obtain the desired hydrogen production.

The conversion to renewable energy can be achieved when cities and communities start to depend on sustainable resources capable of providing for the basic needs of the community along with a reduction in the daily problems and issues that people face. These issues such as poverty hunger sanitation and economic difficulties are highlighted in the Sustainable Development Goals (SDGs) which aim to limit and eradicate these problems along with other environmental obstacles including climate change and Greenhouse Gases (GHGs). These SDGs containing 17 goals target each sector and provide propositions to solve such devastating problems. Hydrogen contributes to the targets of these sustainable developments since through its implementation in different industries the levels of GHG will drop and thus contribute to the climate change which Earth is facing. Further through the usage of such resources many job opportunities will also be developed thus enhancing the economy and lifting the status of society. This paper classifies the four different types of hydrogen and outlines the differences between them. The paper then emphasizes the importance of green hydrogen use within the shipping industry transportation and infrastructure along with economic and social development through job opportunities. Furthermore this paper provides case studies tackling green hydrogen status in the United Kingdom United States of America and European Union as well as Africa United Arab of Emirates and Asia. Finally challenges and recommendations concerning the green hydrogen industry are addressed. This paper aims to relate the use of green hydrogen to the direct and indirect goals of SDG.