Global Energy System Research Articles

Recent Developments in Materials for Physical Hydrogen Storage: A Review.

The depletion of reliable energy sources and the environmental and climatic repercussions of polluting energy sources have become global challenges. Hence, many countries have adopted various renewable energy sources including hydrogen. Hydrogen is a future energy carrier in the global energy system and has the potential to produce zero carbon emissions. For the non-fossil energy sources, hydrogen and electricity are considered the dominant energy carriers for providing end-user services, because they can satisfy most of the consumer requirements. Hence, the development of both hydrogen production and storage is necessary to meet the standards of a "hydrogen economy". The physical and chemical absorption of hydrogen in solid storage materials is a promising hydrogen storage method because of the high storage and transportation performance. In this paper, physical hydrogen storage materials such as hollow spheres, carbon-based materials, zeolites, and metal-organic frameworks are reviewed. We summarize and discuss the properties, hydrogen storage densities at different temperatures and pressures, and the fabrication and modification methods of these materials. The challenges associated with these physical hydrogen storage materials are also discussed.

Drivers of Global Mineral Demand: 1900–2050

Editor’s note: The aim of the Geology and Mining series is to introduce early career professionals and students to various aspects of mineral exploration, development, and mining in order to share the experiences and insight of each author on the myriad of topics involved with the mineral industry and the ways in which geoscientists contribute to each. Abstract The global demand for minerals has long been known to be characterized by periods of high demand followed by periods of low demand. These are often referred to as cycles. There are cycles of short (multiyear) duration and cycles of long (multidecade) duration. This paper seeks to explain the driving forces behind the long-duration cycles. There have been five such cycles since 1900. Four of them were in the 20th century, and the fifth was the China mining boom, which lasted from about 2000 to 2015. I interpret the main driver of these cycles to be the pace of urban, or suburban, construction. When this is proceeding at a rapid pace, global mineral demand is high. When construction activity slows, mineral demand slows with it. In the 20th century it was the nations of Europe, North America, and, later in the century, the Soviet Union and Japan that were home to most of the world’s construction activity. Their economic fortunes drove the century’s four long-duration cycles. The century began with a 30-year period of high demand driven by the transformation of these economies from predominantly agriculture based to predominantly urban industrial. It ended with a nearly 30-year period of low demand as these same economies, having already urbanized, moved into being predominantly service-based economies, which have a lower per capita mineral demand. At the beginning of the 21st century, China took the lead with its remarkable transformation from an economy that was farm based to one that was urban industrial, which drove global mineral demand to a high level. I argue that the world is now heading into a 30-year period of low urban construction-driven demand as China turns away from reform, India discovers that its economic success is built on weak foundations, and the “advanced countries” continue with their metals-lite transformation toward ever more sophisticated service activities. However, urban construction may be about to be displaced as the principal driver of global mineral demand. This new driver is the restructuring of global energy systems, or, to be more specific, the shift from hydrocarbon-based energy to solar and wind-based energy. Producing energy from solar and wind is far more materials-intensive than from hydrocarbons. Will this shift propel global mineral demand back to high?

It’s a Material World

Abstract One of the greatest challenges of this century is the reduction or elimination of worldwide greenhouse gas emissions, primarily by moving the global energy system from carbon-based fuels to low- or zero-carbon systems. The energy systems that produce carbon emissions are inherently physical and must be replaced by other physical systems, which means the material constraints of building this new infrastructure cannot be ignored.

Global energy trends in the context of climate and environmental transformations

The article is devoted to the study of issues of energy policy formation in nine changing climatic and environmental vectors. A retrospective analysis of the impact of the climate agenda on the energy intensity of global GDP and greenhouse gas emissions was carried out. The authors present a “time line” from 1972-2022, demonstrating the connection between the adoption of a number of key international documents aimed at achieving global environmental and climate goals, and the dynamics of growth rates in the energy intensity of global GDP and greenhouse gas emissions. According to data from 2010-2022, it is shown that the policy of replacing traditional fossil hydrocarbon fuel and energy resources with renewable energy sources in the global energy balance helps to overcome environmental and climate problems, positive results have been identified, in particular, a steady trend of transformation of development scenarios of the global energy system through the introduction of low-carbon and carbon-free technologies, primarily hydropower, solar photovoltaic energy, and wind energy. An inversely proportional relationship is observed, demonstrating several trends: a decrease in the capital intensity of renewable energy sources, a decrease in the costs of the process of their implementation and operation. The results of the study allow us to state the consistency of processes in relation to changes in the dynamics of global GDP and greenhouse gas emissions, while in recent years the growth rate of greenhouse gas emissions at the global level is lower compared to the growth rate of GDP, which proves the effectiveness of the measures being implemented. The materials presented in the article can be used to develop theoretical models and applied measures to implement scenarios for decarbonization of economic systems, increasing their environmental sustainability and mitigating climate change.

A Decision Support System Based on Hybrid Approach With Copras And Interval Type-2 Fuzzy Topsis For Evaluation Of Renewable Energy Alternatives

Renewable energy (RE) is a vital source for the sustainable development of society and economy. It plays a significant role in meeting energy requirements of both developed and developing countries. Moreover, renewable energy creats multiple benefits such as environmental improvement, increases fuel diversity, reduction of energy price, volality effect on their economy, national economic security, and increases in economic productivity. Selection of the most appropriate RE alternatives for any country can provide guidelines to planners of regional, national and global energy systems. The issue of ranking renewable energy sources involves many conflicting criteria and is a complicated problem since it needs to simultaneously incorporate technical, economic, cost, social-political, and environmental criteria. In this study, an integrated multi criteria decision making (MCDM) aproach consisting of interval type-2 fuzzy Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Compressed Proportional Assessment (COPRAS) method is conducted to prioritize RE alternatives in order to direct planning of the national RE investments. A real case application for Turkey has been presented via expert evaluations to demonstrate applicability of the proposed methodology.

Assessing the implications of hydrogen blending on the European energy system towards 2050

With the aim of reducing carbon emissions and seeking independence from Russian gas in the wake of the conflict in Ukraine, the use of hydrogen in the European Union is expected to rise in the future. In this regard, hydrogen transport via pipeline will become increasingly crucial, either through the utilization of existing natural gas infrastructure or the construction of new dedicated hydrogen pipelines. This study investigates the effects of hydrogen blending in existing pipelines on the European energy system by the year 2050, by introducing hydrogen blending sensitivities to the Global Energy System Model (GENeSYS-MOD). Results indicate that hydrogen demand in Europe is inelastic and limited by its high costs and specific use cases, with hydrogen production increasing by 0.17% for 100%-blending allowed compared to no blending allowed. The availability of hydrogen blending has been found to impact regional hydrogen production and trade, with countries that can utilize existing natural gas pipelines, such as Norway, experiencing an increase in hydrogen and synthetic gas exports from 44.0 TWh up to 105.9 TWh in 2050, as the proportion of blending increases. Although the influence of blending on the overall production and consumption of hydrogen in Europe is minimal, the impacts on the location of production and dependence on imports must be thoroughly evaluated in future planning efforts.

(Invited) SOEC Upscale; Material Challenges

To ensure the transition of the global energy system to a sustainable one, and to meet emission reduction targets of national climate policies we need in future to produce large amounts of “green” hydrogen. This will be necessary to sustain the world’s need for synthesis of “green” ammonia, “green” methanol and “green” jet fuels, but also for use in form of hydrogen as a transportation fuel and a reduction agent in steel making. Various electrolysis technologies for providing this hydrogen via an electrochemical splitting of water/steam are likely to become the backbone of this emerging sector.Among the different electrolysis technologies, available or under development, SOEC stands out with distinct advantages related to the high temperature of operation, most markedly; 1) there is no need for precious metals in the electrodes, and 2) the achievable efficiency is higher than for the other electrolysis technologies. The electrical efficiency may exceed 90 % as the technology can be run thermo-neutrally producing no waste heat, or may even utilize waste heat if such exist for instance from a down-stream upgrading of the hydrogen to methanol or ammonia.In view of these very significant advantages, SOEC is likely to become a key enabling technology for the above described transition. However, the SOEC technology is less mature than alkaline electrolysis and PEM-based electrolysis and is today deployed much less than the other two technologies. The largest SOEC units manufactured/operated today are in the range of ~1 MW. However, numerous scale up projects have recently been announced and the industrial stakeholders are these years investing massively to bring up production capacity and module sizes.In this paper we shall discuss some of the challenges in upscaling SOEC and some of the materials issues to be addressed, when considering large scale global deployment over the next decades.The inherent brittle nature of the ceramics used in the cells has so far limited the size of the cells of most stakeholders to be in the range with side-lengths from 10 to 15 cm. Ideally, in terms of upscaling module sizes, this should be much larger. This however requires great care in the manufacturing, and a tough and strong backbone material in the cell. Most stakeholders rely on stabilized zirconia to provide the structural support. Use of zirconia in the transformable (metastable) tetragonal version with 2 – 4 % Y2O3 substitution holds some advantages over the use of the fully stabilized cubic version with ~8 % Y2O3, as the former has much higher strength/toughness. We shall present our recent results on optimizing composition and processing routes to maximize toughness and strength, whilst preventing unintended spontaneous transformation to the monoclinic phase during use, and shall discuss the consequences in terms of upscaling cell foot-print.In SOEC one does not need any precious metals (PGM-materials). However, typically the state of the art cells relies on use of several critical raw materials. Several rare earth materials (HREE/LREE) are used (Ce, Gd, Y, La) and also some critical transition metals like Co/Mn and Ni. Ni is by EU not considered critical, but is on the list of strategic materials. For large-scale deployment, it is obviously an advantage if the use of Critical Raw Materials (CRM) can be minimized.Introducing performance improvement in terms of increased production capacity per m2 of cell or kg of material is a straightforward strategy to reduce the CRM-use of the technology and is likely a part of the strategy among all stakeholders. Endeavors to reduce the use of one particular material are also meaningful in such a materials resource perspective.We shall here present recent results on activities to increase the competitiveness of the SOEC technology by introducing a metal-support as the structural backbone and replace the Ni/YSZ-fuel electrode with one based on a mixed conducting Ti-based oxide (Ni and Fe-doped (La,Sr)TiO3). Recently, we have found that such a material combination can in fact sustain SOEC operation for extended periods (tested over 5000 hr) at technologically relevant hydrogen production rates corresponding to current densities of 0.5 A/cm2. The results shall be presented and the possibilities to improve the titanate backbone further by compositional changes shall be discussed with special view to eliminating use of HREE/LREE and critical raw materials in general.Finally, we shall present some recent results on how to eliminate the use of Co in the oxygen electrode. The achieved results shall be compared with other approaches adopted in literature on how to eliminate use of Co and even La in the oxygen electrode.

OPTIMAL JOINT USE OF ALTERNATIVE ENERGY SOURCES

The main structural features and operating principles of alternative energy sources are analyzed, the advantages and disadvantages of each of them are determined, as well as their role in the global energy system. It is shown that the efficient use of solar and wind energy, as well as biological and geothermal energy resources, will meet the electricity needs of developing industries and growing populations around the world, save fuels such as hydrocarbons and coal extracted from mineral deposits and to protect the environment, to reduce the pollution of it. It is noted that the basis for the effective operation of alternative energy sources is the correct economic justification of their use, determination of optimal operating modes and options for connecting these energy sources when used together with traditional energy sources and shows the need to develop an optimal selection algorithm to improve transition processes by reducing commutation, considering possible priorities in the grid. Keywords: solar, wind, thermal, bioenergy, joint use

Low risk management intervention: Limited impact of remedial tillage on net ecosystem carbon balance at a commercial Miscanthus plantation.

Perennial bioenergy crops are a key tool in decarbonizing global energy systems, but to ensure the efficient use of land resources, it is essential that yields and crop longevity are maximized. Remedial shallow surface tillage is being explored in commercial Miscanthus plantations as an approach to reinvigorate older crops and to rectify poor establishment, improving yields. There are posited links, however, between tillage and losses in soil carbon (C) via increased ecosystem C fluxes to the atmosphere. As Miscanthus is utilized as an energy crop, changes in field C fluxes need to be assessed as part of the C balance of the crop. Here, for the first time, we quantify the C impacts of remedial tillage at a mature commercial Miscanthus plantation in Lincolnshire, United Kingdom. Net ecosystem C production based on eddy covariance flux observations and exported yield totalled 12.16 Mg C ha-1 over the 4.6 year period after tillage, showing the site functioned as a net sink for atmospheric carbon dioxide (CO2). There was no indication of negative tillage induced impacts on soil C stocks, with no difference 3 years post tillage in the surface (0-30 cm) or deep (0-70 cm) soil C stocks between the tilled Miscanthus field and an adjacent paired untilled Miscanthus field. Comparison to historic samples showed surface soil C stocks increased by 11.16 ± 3.91 Mg C ha-1 between pre (October 2011) and post tillage sampling (November 2016). Within the period of the study, however, the tillage did not result in the increased yields necessary to "pay back" the tillage induced yield loss. Rather the crop was effectively re-established, with progressive yield increases over the study period, mirroring expectations of newly planted sites. The overall impacts of remedial tillage will depend therefore, on the longer-term impacts on crop longevity and yields.

Global energy scenarios: A geopolitical reality check

The ongoing Global Energy System Transformation (GEST) has attracted the attention of multiple academic disciplines and practitioners, approaching the process with different analytical and conceptual tools. We explore the ‘integration gap’ that exists between, on the one hand, Energy System Modelling and the stylised scenarios they use, and on the other, energy geopolitics. We consider how these approaches can complement each other to further our understanding of the global energy system’s future. Using a novel qualitative analytical framework, we review the extent to which a range of state-of-the-art global energy scenarios capture and reflect key issues in energy geopolitics in their narratives and model implementation. We find that few scenarios consider geopolitics in any depth. Those that do often treat it as a barrier to decarbonisation efforts that are aligned with the climate objectives of the Paris Agreement. Normative, Paris-aligned scenarios describe smooth processes of change where cooperation and coordination between countries are assumed and where geopolitics is often completely absent. Our findings emphasise the need for a more intricate understanding of the difference between ‘paper transitions’ and the real-world messiness and complexities of GEST, where geopolitics has a dual quality of simultaneously accelerating and hindering the transformation process.

Hybrid ultra-short-term PV power forecasting system for deterministic forecasting and uncertainty analysis

The rapid development of the photovoltaic industry provides a new source of power for the continued operation of the over-consumed energy world. While providing new opportunities for global energy systems, it also poses challenges for power grids. Therefore, it is a priority to fully grasp the characteristics of photovoltaic changes and accurately forecast and analyze them. To enrich the existing research, a novel hybrid prediction system considering meteorological factors is constructed. First, a feature selection module is introduced to select features and assign weights to exogenous meteorological factors, which breaks through the limitations of single-data dimension prediction. Second, shallow and deep learning models are flexibly applied and multi-objective intelligent optimization strategies are introduced to construct deterministic combinatorial prediction models. The module can effectively increase the diversity of prediction models while fully weighing the accuracy and stability of prediction to meet the needs of different information users. Finally, an interval prediction model is constructed to further enrich the PV power prediction system from the perspective of uncertainty analysis. The empirical study is carried out with 5-minute interval data at three sites, and the results show that the hybrid system obtains superior out-of-sample forecasting performance with technical feasibility and general applicability.

A Review of Rural Household Energy Poverty: Identification, Causes and Governance

Energy poverty is one of the three major crises of the global energy system. It tends to deepen as a result of the imbalance between supply and demand, energy transition and financial factors, especially in rural areas of developing countries. This paper took rural household energy poverty as the subject and collected 27 Chinese papers and 44 English papers from Google Scholar, Sci-hub, CNKI and other academic websites in the academic field on the definition, identification methods, influencing factors and governance countermeasures of energy poverty. It focused on analyzing the influence of income level, geographic location, urban–rural differences, demographic characteristics and other factors on energy poverty, as well as the profound impact of energy poverty on the population’s health, the population’s economic status, social equity, welfare of the population, the national economic development, etc. It finally landed on the government’s countermeasures to govern energy poverty so as to provide references for solving the problem of energy poverty by systematically sorting out the literature.

Living Lab for the design and activation of energy communities in the inner areas

In order to accelerate the “green and digital” transition and the achievement of carbon neutrality objectives, the EU has launched a profound transformation of the global energy system in the regions of member countries. In this context, the research project, which addresses the reduction in impacts from climate change through mitigation and adaptation processes and strategies, has the objective of activating a demonstration (Living Lab) in the SNAI pilot area “Grecanica” (RC). It envisages developing and transfering advanced sustainable technologies for “energy self-production of communities”, with processes enabled by technologies belonging to advanced systems for customised production and distributed generation from renewable sources, smart grids and digital flow management.

The effect of heterogeneous national technological capabilities on a Net-zero energy system

Numerous studies have linked the heterogeneous nature of national technological capabilities to the disparities in country-level low-carbon investment patterns. This study investigates how differences in national and regional technological capabilities can impact the pathway to a global net-zero energy system using an integrated assessment modeling approach. The study begins by developing a novel metric that captures the heterogeneity of national low-carbon technological endowments. The metric is then modeled to explore the regional and global low-carbon investment and CO2 abatement trends. Modeling results reveal that the heterogeneity of low-carbon technological competencies induces an asymmetry in low-carbon investments across countries and regions. This asymmetry is driven by a low-carbon investment gap created by developing economies with inferior technological capabilities. Conversely, frontier low-carbon technology regions increase their technology deployment efforts to compensate for the investment deficits. The resultant impact of the asymmetry leads to a moderate but non-trivial increase (i.e., 5.1 to 9.3 %) in the policy cost for achieving the net-zero energy target. Insights gleaned from this computational thought experiment reassert the importance of supporting local technological capabilities in the context of global climate mitigation.

Objective limitations of the current vector of ESG-transition development

Aim. To identify objective reasons for the slowdown of ESG-transition, as well as a list of risks and limitations of the current vector of development of the climate agenda, which are often ignored by developers of “green” standards and taxonomies.Tasks. To evaluate ESG transition initiatives during the COVID-19 coronavirus pandemic; to identify non-obvious barriers and constraints to ESG transition; and to uncover the reasons that have shaped the current vector of the climate agenda.Methods. The study is based on the analysis of empirical data. Their processing showed that ideas of the international climate agenda are often broadcast regarding the ESG topic, but there are very few critical articles and reviews about it.Results. The current vector of development of the climate agenda is primarily conditioned by the goals of its initiators - international economic organizations. These include the Organization for Economic Cooperation and Development (OECD), the International Monetary Fund (IMF) and the World Trade Organization (WTO). The propagated notions of global environmental crises that future generations will inevitably face unless measures are taken to facilitate the transition to sustainable development are only a political tool for competing in the hydrocarbon market. Given the lack of strong technological solutions, investments in green assets can be seen as high-risk given their speculative nature.Conclusions. Despite the priorities of the global economic agenda, there are doubts about its integrity, as it fails to take into account a number of constraints and circumstances, including failure to take into account the scale of the raw material strain required to transform the global energy system; the lack of technologies to efficiently process large volumes of retired so-called renewable energy sources; the lack of energy technologies for which demand is not yet evident; and the “rebound” effect, i.e. the question of what happens next. As a result, market participants often use so-called greenwashing (or “green camouflage”) to formally meet the requirements, or rather, to portray the “greenness” of their technology/products.

Green hydrogen and an evolving concept of energy security: Challenges and comparisons

The electrification of the global energy systems via renewable resources is seen as a key method of decarbonization but as not all energy demand can be easily electrified new solutions are needed. One of them is hydrogen. Production of green hydrogen requires large amounts of renewables, wind and solar, and water. The transition to a net-zero energy system changes the geopolitics of energy and while alleviating some problems might cause others. In this paper we firstly map the evolution of the energy security concept and the place of hydrogen in that discussion. Although a transition to a green energy system is considered a positive development taking into consideration the climate needs, the shift itself may also bring challenges. We point out three categories of risks linked to the wider use of green hydrogen: geopolitical, market and trade challenges. Secondly, we evaluate the cost of green hydrogen and its derivatives from eight exporting countries to the port of Rotterdam and evaluate cost developments in several 2035 and 2050 scenarios.

State-of-art of Liquid Hydrogen Carriers: Trends in the Selection of Organic Molecules

Abstract: Nowadays, fossil fuels represent the main energy source. According to the BP Statistical Review of World Energy report, in 2021, global energy consumption amounted to 595.15 EJ of which 82% was generated from natural gas, oil and coal. The energy consumption growth, rapid depletion of fossil fuels and increasing pressure on the environment threaten the continued sustainability of the global energy system. In this context, renewable energy sources (RES), which now account for 6.7% are attracting increasing attention. The key obstacles to the introduction of RES (solar, wind geothermal, etc.) are their nonstationarity due to seasonality, meteorology and differences in geoclimatic conditions. In this regard, an important role is played by the development of technologies for efficient storage and transportation of renewable energy to consumers. One of the most promising storage technologies is the processing of renewable energy into hydrogen, which, due to the high mass energy intensity (120 MJ⋅kg-1) and environmental friendliness, can be considered a promising energy carrier. Nevertheless, the widespread use of hydrogen as a fuel is limited due to the low volumetric energy density and high explosiveness. Thus, along with the development of technologies for processing renewable energy sources into hydrogen (e.g., electrolysis), a large number of studies are focused on the development of technologies for storage and transportation. This study provides a brief overview of the state of the art of these technologies, with a focus on technology based on the use of liquid organic hydrogen carriers (LOHCs).

Comparison of green ammonia and green hydrogen pathways in terms of energy efficiency

The global energy system transition necessitates new energy carriers with low greenhouse gas emissions. Chemical energy storage technologies provide a viable basis for long-term energy storage. Ammonia is a promising approach in this regard. This study takes a closer look on the energetic potential of ammonia as energy carrier compared to hydrogen. The efficiencies of five green ammonia and four green hydrogen pathways are evaluated for production, storage and utilisation on a power-to-X-to-power basis. The round-trip efficiency for each pathway is calculated by comparing the energy demand that each individual technology requires along the pathways and the usable electric energy that is provided at the end of the pathways. The most efficient pathway for ammonia turns out to be a combination of a decomposition-unit and a solid-oxide fuel cell with a round-trip efficiency of 28 ± 5 % for 30-day storage duration. This is similar to the value for the most efficient pathway using hydrogen. Pathways utilising ammonia are energetically particularly beneficial compared to the hydrogen pathways in case of long storage duration.

Development of Non-Spherical Platinum Nanoparticles on Carbon Supports for Oxygen Reduction Reaction

Proton exchange membrane fuel cells are anticipated to play an important role in decarbonizing the global energy system, but the performance of platinum (Pt) catalysts must be improved to make this technology more economical. Studies have identified non-spherical Pt nanoparticles on carbon supports as promising approaches to address this challenge. However, to realize the full benefits of these strategies, the catalyst synthesis procedures must be successfully simplified and scaled up, and the catalyst must perform well in half and full-cell tests. In this study, a surfactant-free one-pot method is developed to synthesize non-spherical Pt nanoparticles on Ketjen Black carbon, which is either non-treated (Pt/KB), acid-treated (Pt/KB-O), or nitrogen-doped (Pt/KB-N). The catalysts are synthesized in both small and large batches to determine the effect of scaling up the synthesis procedure. The nitrogen-doped carbon support shows a nearly identical morphological structure with uniform distribution of non-spherical Pt nanoparticles for both small and large batches’ synthesis compared with non-treated and acid-treated carbon samples. The comparative oxygen reduction reaction (ORR) activity shows that the Pt/KB-N prepared in small and large batches has better ORR activity, which is likely caused by uniformly distributed non-spherical Pt nanoparticles on the nitrogen-doped carbon support. All three catalysts show similar ORR durability, testing from 0.5–1.0 V, while Pt/KB-O displays slightly better durability from 1.0–1.5 V for carbon corrosion. These results will help inform the implementation of shape-controlled Pt catalysts on modified carbon supports in large scale.

Recent legislation in the United States: consequences for the US and global energy and climate innovation systems

This Perspective sketches how recent legislation in the United States may impact the domestic and global energy and climate innovation systems, drawing on systems concepts articulated by Arnulf Grubler. It also sets out risks and gaps that could lead to less favorable outcomes.