Chile

The competition between chemical energy release rate and volumetric expansion related to shock wave’s dynamics is of primary importance for a number of situations relevant to explosion safety. While studies have been performed on this topic over the years they have been limited to mixtures with monotonous energy release profile. In the present study the ignition of H2-NO2/N2O4 mixtures which exhibit a single-step or a two-step energy release rate profile depending on the equivalence ratio has been investigated under volumetric expansion conditions. The rate of expansion has been calculated using the Taylor-Sedov solution and accounted for using 0-D numerical simulations with time-dependent specific volume. The results were analyzed in terms of a Damkohler number defined as the ratio of the expansion to ignition times. For mixtures with non-monotonous energy release rate profiles two critical Damkohler numbers can be identified one for each of the steps of energy release. It was also shown that the fluid element which is the most likely to ignite corresponds to the one behind a shock propagating at the Chapman-Jouguet velocity. The thermo-chemical dynamics have been analyzed about the critical conditions using energy release rate per reaction rate of production and sensitivity analyses.

The paper presents a complete value chain for the use of green hydrogen in a port facility. The main objective was to propose the sizing of the main components that make up green hydrogen to ensure the supply of 1 MWe in replacing the diesel generator. The energy demand required for the port was determined by establishing the leading small and large-scale conventional energyconsuming equipment. Hence 60 kgH2 was required to ensure the power supply. The total electrical energy to produce all the hydrogen was generated from photovoltaic solar energy considering threegeneration scenarios (minimum maximum and the annual average). In all cases the energy supply in the electrolyzer was 3.08 MWe. In addition the effect of generating in the port facility using a diesel generator and a fuel cell was compared. The cost of 1 kgH2 could be 4.09 times higher than the cost of 1 L of diesel meaning that the output kWh of each system is economically similar. In addition the value of electrical energy through a Power Purchase Agreement (PPA) was a maximum of 79.79 times the value of a liter of diesel. Finally the Levelized Cost of Energy (LCOE) was calculated for two conditions in which the MWe was obtained from the fuel cell without and with the photovoltaic solar plant.

As result of the adverse effects caused by climate change the nations have decided to accelerate the transition of the energy matrix through the use of non-conventional sources free of polluting emissions. One of these alternatives is green hydrogen. In this context Chile stands out for the exceptional climate that makes it a country with a lot of renewable resources. Such availability of resources gives the nation clear advantages for hydrogen production strong gusts of wind throughout the country the most increased solar radiation in the world lower cost of production of electrical supplies among others. Due to this the nation would be between the lowest estimated cost for hydrogen production i.e. 1.5 USD/kg H2 approximately scenario that would place it as one of the cheapest green hydrogen producer in the world.

The article presents a review of the research on green hydrogen from the social sciences identifying its main lines of research its problems and the relevant challenges due to the benefits and impacts that this energy vector has on energy transitions and climate change. The review analyzes a corpus of 78 articles indexed in the Web of Science (WoS) and SCOPUS published between 1997 and 2022. The review identified three research areas related to green hydrogen and the challenges for the social sciences in the future: (a) risks socio-environmental impacts and public perception; (b) public policies and regulation and (c) social acceptance and willingness to use associated technologies. Our results show that Europe and Asia lead the research on green hydrogen from the social sciences. Also most of the works focus on the area of public policy and regulation and social acceptance. Instead the field of social perception of risk is much less developed. We found that little research from the social sciences has focused on assessments of the social and environmental impacts of hydrogen on local communities and indigenous groups as well as the participation of local authorities in rural locations. Likewise there are few integrated studies (technical and social) that would allow a better assessment of hydrogen and cleaner energy transitions. Finally the lack of familiarity with this technology in many cases constitutes a limitation when evaluating its acceptance.