Green hydrogen's role in energy transition and water issues

The potential reshaping of global energy markets by hydrogen: Following the trend of interest in hydrogen in recent history, there is a growing belief that green and low-carbon hydrogen will play a critical role in the transition to a zero-carbon economy. This is evidenced by the breadth and depth of hydrogen strategies and roadmaps that have emerged around the world in recent years [1-2]. The goals of a new clean hydrogen sector go far beyond decarbonisation. Clean hydrogen offers the opportunity to develop new supply chains, jobs and innovation, and to radically reshape the global economy and the geopolitics of the energy sector more generally. For countries without fossil fuel resources, hydrogen could reduce their dependence on imports or even turn them into energy exporters. For countries that are rich in fossil fuels, hydrogen may be able to be used as part of a just transition to a more sustainable future. Hydrogen, by democratising the means of production, coupled with abundant and cheap renewable electricity, could help to reduce instability in global energy markets and alleviate energy poverty. For this reason, some researchers argue that the growth of green hydrogen within the global economy could lead to such geo-economic and geopolitical changes, in which new scenarios and interdependencies will be shaped [3,4,5]. In this scenario, traditional oil and gas trade is expected to shrink. According to the outlook drawn up by IRENA, green hydrogen will cover 12% of global energy consumption by 2050. This will be due to targeted investments in the sector that will increase economic competitiveness and change the current hydrocarbon-based relationships [6]. 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. With regard to future value chains for the production of green hydrogen-based ammonia, methanol and green steel, according to Eicke & De Blasio [7], changes can be expected within the global market that will lead some countries to take other positions than they currently have. For instance, with respect to the production of green hydrogen-based methanol, four countries - Saudi Arabia, Trinidad and Tobago, Oman and the United Arab Emirates - with a total world market share of 39%, are limited in their potential for green methanol production. The consequence of this will be that these countries will have to rely on imports to maintain their position in the future green methanol market. On the contrary, countries such as New Zealand, Norway or Chile, which currently do not have significant market shares in this sector, could, given their resources and economic conditions, sharpen their positions. The issue of renewable fresh water: One issue that is at the centre of the debate on what the impacts of a widespread deployment of green hydrogen might be concerns water resources. Researchers from various scientific fields are comparing and assessing the effect of green hydrogen on the global water resource. The key question is: will there be enough water to meet our future demand for green hydrogen? The views and scenarios that can be drawn from the literature and reports by various international bodies make different predictions. A research conducted by Newborough & Cooley [8] states that if all current fossil fuels used were converted to green hydrogen, the need for water for electrolysis would amount to 1.8% of the current global water consumption. However, even if the consumption of water to produce hydrogen is less than that required to produce energy from fossil fuels, concerns over the scarcity of fresh water call for a reduction in the use of water sources. Some researchers see a feasible and concrete sol