Analisi dell’impatto locale della produzione di idrogeno verde sulla disponibilità di acqua dolce e possibili misure di mitigazione: Il caso di NextHY.

Master thesis overview

Alessandro Luppi
MSc in Engineering Structures for the Environment
2023 - 2024
Analysis of the local impact of green hydrogen production on freshwater availability and possible mitigation measures: The case of NextHY
Master Thesis Director: Prof. Della Valle Giuseppe
“Politecnico di Milano does not express approval or disapproval concerning the opinions given in this paper which are the sole responsibility of the author.”

Table of contents

• Introduction....................................................................................................... 4
• Literature review................................................................................................. 8
• Blanco H., 2021, July 22. “Hydrogen production in 2050: how much water will 74EJ need?” Retrieved from https://energypost.eu/hydrogen-production-in-2050-how-much-water-will-74ej-need/.................................................................................. 11
• Research method............................................................................................ 14
• Structure........................................................................................................ 16
• The energy-water nexus..................................................................................17
• Energy-water nexus in the context of green hydrogen production...........22
• Role of climate change on the availability of freshwater.....................28
• Strategic positioning of GH2 plants.......................................................31
• Role of policies, technologies, and measures at a local level..................36
• Case study – The NextHY GH2 project in Carlentini..........................................41
• Evaluation of water stress and scarcity in the region..................................45
• Data collection............................................................................................ 51
• Method........................................................................................................ 59
• Results......................................................................................................... 61
• Conclusion and recommendations.................................................................76
• Importance of collecting data, continuous monitoring, and adaptation.......80
• References............................................................................................................ 82

References
I certify that: the master project being submitted for examination is my own research, the data and results presented are genuine and actually obtained by me during the conduct of the research and that I have properly acknowledged using parenthetical indications and a full bibliography all areas where I have drawn on the work, ideas, and results of others.

Abstract

This study investigates the extent to which green hydrogen production affects local freshwater availability, a crucial resource for survival. The research evaluates various factors contributing to water scarcity and underscores the importance of policies and innovation to mitigate associated risks. Employing a comprehensive methodology that includes expert interviews and thematic analysis, the study focuses on a real-world case: the Green Hydrogen plant in Carlentini, Sicily, part of ENEL's "NextHy" project. Data, facilitated by the ENEL Hydrogen Project Developer, reveals that while the plant itself has minimal impact on water resources, external factors such as climate change and rising demand exacerbate local water stress. Key indicators used are the Water Scarcity Footprint (WSF) and Water Stress Index (WSI). The findings highlight the need for sustainable water management practices and long-term monitoring to mitigate future environmental and social impacts of green hydrogen projects.

Abbreviations

• RES: Renewable Energy Sources
• WSI: Water Stress Index
• WSF: Water Scarcity Footprint
• WCEP: Water Consumption for Energy Production
• WEP: Water Withdrawal for Energy Production
• GH2: Green Hydrogen
• PV: Photovoltaic
• CO2: Carbon Dioxide

Introduction

The vast majority of countries worldwide in recent years have been hit by the devastating effects of climate change with extreme weather events (flooding, prolonged droughts, and sea-level rise). These events represent the tip of the iceberg of the climate catastrophe that likely awaits us unless global governments, especially those of the most developed countries, implement policies aimed at mitigating the effects of climate change and strategies aimed at both eliminating the main causes of these effects and adapting countries to a hypothetical coexistence with these changes.

One "positive" piece of news is that the recent increase in these climate events has heightened attention and pressure on participants at COP-25, the United Nations Conference on Climate Change, which concluded in November 2021 to finally implement measures to reduce greenhouse gas emissions. The bad news is that everything agreed upon at COP-25 is unlikely to make a positive difference, as the document lacks concrete actions and specific methods to limit temperature growth to 1.5°C (Streck, et al., 2020). Faced with the accelerating pace of climate change and its resulting natural disasters, it is clear that most governments in most countries must undertake a series of policies and measures to combat the adverse conditions caused by climate change (Le Quéré et al., 2019).

Among the factors that affect the climate issue, one of the most relevant, as is known, concerns the mode of energy production. Most of the energy produced is made from combustion processes, causing severe environmental consequences, changing ecosystems, and health problems (Olabi, et al., 2022). As highlighted by the International Energy Agency in their report (IEA, 2020), the energy sector is one of the cornerstones to respond to the global climate challenge as it is the cause of about 75% of global greenhouse gas emissions. According to the IEA report (2022), in 2022 alone the energy sector emitted 38.6 billion tonnes of CO2. Contemporarily, the energy demand is increasing yearly, led by the increasing global population and the evolution and fast industrial growth of BRICS developing countries. For these reasons, countries worldwide have recognized this issue's urgency and taken various measures to promote renewable energy adoption, as more sustainable and environmental-friendly solution. Laws and regulations have been enacted to set renewable energy targets, promote research and development, and create incentives for clean energy production. Subsidies and tax incentives have been implemented to make renewable technologies more affordable and accessible to individuals and businesses.

In this context characterized by growing concerns about climate change, dwindling fossil fuel reserves, and the imperative to transition towards sustainable energy sources, hydrogen, together with other renewable energy sources, have emerged as a promising contender to revolutionize the global energy landscape. Hydrogen, the most abundant element in the universe, possesses the potential to serve as a clean, versatile, and highly efficient energy carrier, capable of addressing various energy and environmental challenges.

This study focuses on the green hydrogen (GH2) production process, a type of hydrogen gas produced using renewable energy sources, called shortly RES, usually considered as a minimal environmental impact production process. First, it is considered a clean and sustainable energy carrier because it is produced using electrolyzes supplied by renewable electricity. Secondly, it can be generated without emitting greenhouse gases or other harmful pollutants. For this reason, it can help reduce greenhouse gas emissions and dependency on fossil fuels while providing a reliable and versatile energy source.

Central to the production of hydrogen, a key driver of its viability as an energy vector and a focal point for this study is the withdrawal and consumption of water during all production processes. Water, H₂O, is not only a source of hydrogen through various hydrogen production methods but also an integral component of the hydrogen economy's sustainability and environmental footprint, as emphasized by Stenberg and Bardow (2015). Furthermore, it's extremely relevant to consider that, as highlighted by Al-Qahtani et al. (2018, p. 281), "The water consumption is generally in the range of 10–15 L per 1 kg of hydrogen output, and input water needs to be deionized." Not to mention that the volume of additional water needed to cool the plant is not considered, which further increases the supply of water needed for the production of green hydrogen. Ergo, it is immediately visible the high-water required ratio to produce green and clean hydrogen energy through the electrolysis process.

Another relevant study by Mehmeti (2018) emphasizes the possible existence of a trade-off between water-related impacts and emissions. It observed that technologies with lower global warming and fine particulate matter scores tend to have higher water-related impacts.

While water is a seemingly abundant resource on Earth, the distribution and accessibility of freshwater, especially in the context of energy-intensive hydrogen production, present complex challenges, especially at a local level. Balancing the energy demand, that is going to rise in the long-term period, due to both the growing population rate and the new hydrogen production goals (for example, the European Parliament has defined and developed a plan for the implementation and enhancement of Hydrogen Production, which defines three different phases to make the production of green hydrogen one of the main sources of energy) together with the reduced supply of freshwater, due to climate change effects (increased droughts, less rain, heat waves), have highlighted a need to conserve and manage water resources, invest in innovation and evaluate carefully the positioning of GH2 plants worldwide (Deloitte Financial Advisory, 2019).

In the absence of freshwater sources or cases of limited water availability, recent advancements have yielded novel technologies that foster a more circular utilization of water and the direct utilization of saline water within electrolyzers (Patel, 2022; V.G. Gude, 2016). Nevertheless, these technologies remain in a nascent stage of development and still very costly to develop at a larger scale. To address the scarcity of fresh water, desalination facilities are frequently constructed to convert saline water into freshwater for injection into catalysts. While this may constitute a viable solution, it is important to acknowledge that it remains a highly costly process, generates challenging waste disposal issues, and exhibits an exceptionally high energy demand (Omerspahic, M., 2022). In addition, the presence of dirt or high salt concentrations, electrolysis fatigue, and machinery are likely to be damaged.

It is also added that, as rightly pointed out by Noussan, et al. (2021), freshwater availability in non-maritime sites may become a critical issue in many world regions, especially because water scarcity is a serious concern that will become even worse due to climate change. This aspect may become a critical barrier to the success of green hydrogen projects in areas with strong solar potential since they are strategic and favorite places for constructing hydrogen systems, thanks to energy availability to power the electrolyzers.

So the question in this study is to what extent green hydrogen production adequately impacts local freshwater availability, as an essential element for survival, analyzing firstly the role of a series of factors affecting the scarcity and then the importance of setting policies and invest in innovation to reduce or mitigate the risks associated.

Therefore, this is a study aimed at primarily examining the role of green hydrogen as a sustainable energy source in long-term water utilization, analyzing the water consumption of green hydrogen production from the electrolysis process. It is imperative to recognize that future freshwater availability is expected to decrease, especially in some areas of the world already subjected to the climate change effects, while energy demand is poised to rise, intricately linked to population growth and economic development. Moreover, it proposes strategies, technologies, and policies that can optimize water usage at a local level, minimize environmental impacts, and maximize the efficiency and sustainability of hydrogen production processes. Subsequently, it takes into consideration a real case of a GH2 plant located in the south of Italy, typically an area subjected to water scarcity and strongly affected by climate change effects, to understand the long-term consequences on local water availability.

In the face of a potential scarcity of studies on this subject, it could be an opportunity to delve deeper into a theme that has not yet been sufficiently analyzed, contributing to the study of an energy source categorized as green, which is heavily relied upon to reduce CO2 emissions and support the energy transition. At the same time, it would offer a theoretical framework to understand the direct and indirect impact of hydrogen development on water availability.

Literature review

Thanks to the fact H₂ has three times better energy content per unit weight than conventional fuels (Abdin et al., 2020), and it can be produced via water electrolysis with lower environmental impacts, aligning with sustainable development idea, H₂ has been highlighted as one of the most interesting ways to shift to more sustainable energy systems, together with a good addition to the global energy mix to diversify the energy sources.

There are many other different ways in addition to the electrolysis process for drawing up hydrogen. Newborough and Cooley (2020) have distinguished different methods of hydrogen production, linking them to several colors. Based on the colors, following the main, as well as most used to date, methods of hydrogen production:

• Grey (or brown/black) hydrogen: Produced using fossil fuels (mostly natural gas and coal) and results in carbon dioxide emissions during the process.
• Blue hydrogen: Produced by combining grey hydrogen with carbon capture and storage (CCS) technology to minimize greenhouse gas emissions.
• Turquoise hydrogen: Generated through the pyrolysis of fossil fuels, with solid carbon as a by-product.
• Yellow (or purple) hydrogen: Created using electrolyzers powered by electricity from nuclear power plants, offering a low-carbon hydrogen production method.
• Green hydrogen: Produced using electrolyzers powered by renewable electricity sources, with minimal environmental impact.

Every technological hydrogen type of production has its pros and cons, but the ending choice of specific solution development is related to multiple factors, such as government incentives, availability of resources, and energetic concerns (Scita, et al., 2020). To date, the current dominant method of hydrogen production is steam methane reforming (SMR), which uses high-temperature steam to produce hydrogen from methane. This hydrogen is classified as “grey” or “blue” (if combined with carbon capture & and sequestration, called CCS). If not implemented together with CCS technology, there are many social and environmental problems with SMR production linked to GHG emissions: as it is specified by the article of Degli Esposti M. (2021, p. 2), methane is much more harmful to the climate than CO2, if it is dispersed in combustion in the atmosphere. Over the course of 20 years, a tonne of the gas will warm the atmosphere about 86 times more than a tonne of CO2. Furthermore, according to Degli Esposti M. (2021, p. 2), methane emissions are responsible for 23% of the rise in temperatures since pre-industrial times. Hence, if a GHG capture and storage system is added, the problem of methane emissions would be solved efficiently with a capture level of over 90%.

Yet, even with the addition of CCS technology, there is another environmental issue that jeopardizes the most common hydrogen production method, concerning this time the water usage that cannot be overlooked. Indeed, while capable of absorbing and trapping hazardous emissions that would otherwise be released into the atmosphere, it requires an enormous volume of water, in addition to the regular coal production process. Adding CCS to a coal plant would increase its water consumption from 45 percent to 85 percent (Meldrum, J., et al., 2013).

All these reasons lead most national governments' investments and international organizations' incentives towards the development and production of cleaner and less polluted hydrogen, identifying green hydrogen (GH2) as the right compromise as it appears to be in line with the objectives of decarbonization – according to Patel, G. H. et al. (2024) zero CO2 emissions during production process if powered with renewable energy sources, and provides emission reduction of 80–95% compared to grey hydrogen - and cooperative development, together with renewable energy sources usage. For example, the European Commission has set the goal of making green hydrogen a substantial part of the European energy system, with at least 10 million tons of renewable hydrogen by 2030 and 40 GW of electrolyzers installed, with about a quarter used for renewable hydrogen production by 2050 (Directorate General for Energy, 2021).

Despite the emission advantages highlighted earlier by the development of green hydrogen, there is still a problem related to the excessive use of fresh water, which has not been considered sufficiently by national and international governments, especially considering the negative contribution caused by population growth and economic development, together with the effects of climate change on its availability in the long-term timeframe. This last one is especially the most relevant, considering the link between the production of green hydrogen and renewable energy sources.