To face the pollution and global warming issues a shift towards renewable energy technologies is currently running in the world energy mix. Renewable energy in 2016 accounted for less than 15% of produced electricity, nowadays it represents 28% of the world's electricity production and 13.8% of the global energy consumption. The progressive increase of the RES power share in the electric grid introduces issues related to the natural discontinuity and fluctuations of RES, that are the object of an increasing number of investigations, and require energy storage systems to mitigate them. Although there are different possible technologies for energy storage, hydrogen is considered the most suitable choice for massive and long term storage of RES power. This is because hydrogen is an energy vector (fuel) and also a commodity gas and a feedstock for many industrial applications, so that it can also strongly contribute to decarbonisation of a number of sectors defined "hard to abate". Nowadays, almost all hydrogen is produced by Steam Methane Reforming (SMR). About 82% of the produced hydrogen (94 Mt, in 2021) is directly derived from methane, oil and carbon. About 18% is a by-product coming from different production technologies (e.g., naphtha reforming). Therefore, hydrogen produced by low-emission technologies is less than 1 Mt (0.7%), with the majority of this coming from fossil fuels with CCUS (about 0.7%) and only 0.04% (35 kt H2) coming from renewable electricity via water electrolysis. In 2021, the emissions associated with hydrogen production were more than 900 Mt CO2. Hydrogen production costs by these processes are low, $1-2/kg H2 for SMR and $1-1.5/kg H2 for gasification, respectively. The main challenge is how to produce hydrogen for today's and future uses at costs that are close to current ones, but without emitting CO2 into the atmosphere. The two approaches currently able to meet this challenge are "blue hydrogen" and "green hydrogen". But the most important game is played on green hydrogen, the production of which does not entail CO2 emissions as only renewable energy is used. Green hydrogen can be produced by various methods, but the most suitable and well developed technology is based on electrochemical water splitting (electrolysis), then "Green Hydrogen" is usually defined as "Hydrogen made via electrolysis using renewable electricity". This concept has focused the policies of Europe and other developed countries, concentrating investments in this direction forgetting other production paths of green hydrogen. Moreover, focusing the attention to electrolysis some geopolitical and social issues are coming up, like for example the water issue that is related to the necessity of having high purity water for running electrolysis. Some scholars argue that the growth of green hydrogen within the global economy could lead to geo-economic and geopolitical changes, in which new scenarios and interdependencies will be shaped. The consequences will be a different geography of energy trade with the emergence of new centres of geopolitical influence, based on the production and use of hydrogen. In this work, starting form some considerations about available technologies, a wider concept of green hydrogen is defined. In doing so, an overview of the peculiar advantages and shortcomings of different green hydrogen technologies is supplied, with a focus on the electrolysis process as the most promising method for large scale and distributed generation of hydrogen. Some geopolitical and socio-technical aspects associated with the electrolysis and water issue are examined by looking at the hydrogen international policies' plans (including Tunisian one). This with the purpose of supplying to researchers and policy makers an overview of possible solutions and of suggesting them a holistic approach looking at all the possible technologic approaches in front of an approach focused on a single technology.
Green Hydrogen and related policies
G Squadrito
2023
Abstract
To face the pollution and global warming issues a shift towards renewable energy technologies is currently running in the world energy mix. Renewable energy in 2016 accounted for less than 15% of produced electricity, nowadays it represents 28% of the world's electricity production and 13.8% of the global energy consumption. The progressive increase of the RES power share in the electric grid introduces issues related to the natural discontinuity and fluctuations of RES, that are the object of an increasing number of investigations, and require energy storage systems to mitigate them. Although there are different possible technologies for energy storage, hydrogen is considered the most suitable choice for massive and long term storage of RES power. This is because hydrogen is an energy vector (fuel) and also a commodity gas and a feedstock for many industrial applications, so that it can also strongly contribute to decarbonisation of a number of sectors defined "hard to abate". Nowadays, almost all hydrogen is produced by Steam Methane Reforming (SMR). About 82% of the produced hydrogen (94 Mt, in 2021) is directly derived from methane, oil and carbon. About 18% is a by-product coming from different production technologies (e.g., naphtha reforming). Therefore, hydrogen produced by low-emission technologies is less than 1 Mt (0.7%), with the majority of this coming from fossil fuels with CCUS (about 0.7%) and only 0.04% (35 kt H2) coming from renewable electricity via water electrolysis. In 2021, the emissions associated with hydrogen production were more than 900 Mt CO2. Hydrogen production costs by these processes are low, $1-2/kg H2 for SMR and $1-1.5/kg H2 for gasification, respectively. The main challenge is how to produce hydrogen for today's and future uses at costs that are close to current ones, but without emitting CO2 into the atmosphere. The two approaches currently able to meet this challenge are "blue hydrogen" and "green hydrogen". But the most important game is played on green hydrogen, the production of which does not entail CO2 emissions as only renewable energy is used. Green hydrogen can be produced by various methods, but the most suitable and well developed technology is based on electrochemical water splitting (electrolysis), then "Green Hydrogen" is usually defined as "Hydrogen made via electrolysis using renewable electricity". This concept has focused the policies of Europe and other developed countries, concentrating investments in this direction forgetting other production paths of green hydrogen. Moreover, focusing the attention to electrolysis some geopolitical and social issues are coming up, like for example the water issue that is related to the necessity of having high purity water for running electrolysis. Some scholars argue that the growth of green hydrogen within the global economy could lead to geo-economic and geopolitical changes, in which new scenarios and interdependencies will be shaped. The consequences will be a different geography of energy trade with the emergence of new centres of geopolitical influence, based on the production and use of hydrogen. In this work, starting form some considerations about available technologies, a wider concept of green hydrogen is defined. In doing so, an overview of the peculiar advantages and shortcomings of different green hydrogen technologies is supplied, with a focus on the electrolysis process as the most promising method for large scale and distributed generation of hydrogen. Some geopolitical and socio-technical aspects associated with the electrolysis and water issue are examined by looking at the hydrogen international policies' plans (including Tunisian one). This with the purpose of supplying to researchers and policy makers an overview of possible solutions and of suggesting them a holistic approach looking at all the possible technologic approaches in front of an approach focused on a single technology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
