Potential of renewable hydrogen production for energy supply in Hong Kong

Hong Kong is highly vulnerable to energy and economic security due to the heavy dependence on imported fossil fuels. The combustion of fossil fuels also causes serious environmental pollution. Therefore, it is important to explore the opportunities for clean renewable energy for long-term energy supply. Hong Kong has the potential to develop clean renewable hydrogen energy to improve the environmental performance. This paper reviews the recent development of hydrogen production technologies, followed by an overview of the renewable energy sources and a discussion about potential applications for renewable hydrogen production in Hong Kong. The results show that although renewable energy resources cannot entirely satisfy the energy demand in Hong Kong, solar energy, wind power, and biomass are available renewable sources for significant hydrogen production. A system consisting of wind turbines and photovoltaic (PV) panels coupled with electrolyzers is a promising design to produce hydrogen. Biomass, especially organic waste, offers an economical, environmental-friendly way for renewable hydrogen production. The achievable hydrogen energy output would be as much as 40% of the total energy consumption in transportation.     

Optimal design of wind-powered hydrogen refuelling station for some selected cities of South Africa

The transport sector is considered as one of the sectors producing high carbon emissions worldwide due to the use of fossil fuels. Hydrogen is a non-toxic energy carrier that could serve as a good alternative to fossil fuels. The use of hydrogen vehicles could help reduce carbon emissions thereby cutting down on greenhouse gases and environmental pollution. This could largely be achieved when hydrogen is produced from renewable energy sources and is easily accessible through a widespread network of hydrogen refuelling stations. In this study, the techno-economic assessment was performed for a wind-powered hydrogen refuelling station in seven cities of South Africa. The aim is to determine the optimum configuration of a hydrogen refuelling station powered by wind energy resources for each of the cities as well as to determine their economic viability and carbon emission reduction capability. The stations were designed to cater for 25 hydrogen vehicles every day, each with a 5 kg tank capacity. The results show that a wind-powered hydrogen refuelling station is viable in South Africa with the cost of hydrogen production ranging from 6.34 $/kg to 8.97 $/kg. These costs are competitive when compared to other costs of hydrogen production around the world. The cities located in the coastal region of South Africa are more promising for siting wind powered-hydrogen refuelling station compared to the cities located on the mainland. The hydrogen refuelling stations could reduce the CO₂ and CO emissions by 73.95 tons and 0.133 tons per annum, respectively.     

Prospects and challenges for green hydrogen production and utilization in the Philippines

The Philippines is exploring different alternative sources of energy to make the country less dependent on imported fossil fuels and to reduce significantly the country's CO₂ emissions. Given the abundance of renewable energy potential in the country, green hydrogen from renewables is a promising fuel because it can be utilized as an energy carrier and can provide a source of clean and sustainable energy with no emissions. This paper aims to review the prospects and challenges for the potential use of green hydrogen in several production and utilization pathways in the Philippines. The study identified green hydrogen production routes from available renewable energy sources in the country, including geothermal, hydropower, wind, solar, biomass, and ocean. Opportunities for several utilization pathways include transportation, industry, utility, and energy storage. From the analysis, this study proposes a roadmap for a green hydrogen economy in the country by 2050, divided into three phases: I–green hydrogen as industrial feedstock, II–green hydrogen as fuel cell technology, and III–commercialization of green hydrogen. On the other hand, the analysis identified several challenges, including technical, economic, and social aspects, as well as the corresponding policy implications for the realization of a green hydrogen economy that can be applied in the Philippines and other developing countries.     

Wind energy status and its assessment in Turkey

The increase in negative effects of fossil fuels on the environment has forced many countries, especially the developed ones, to use renewable energy sources. Currently the fastest developing energy source technology is wind energy. Because wind energy is renewable and environment friendly, systems that convert wind energy to electricity have developed rapidly. Wind energy is an alternative clear energy source compared to the fossil fuels that pollute the lower layer of atmosphere. Because wind energy will be used more and more in the future, its current potential, usage, and assessment in Turkey is the focus of this study.     

Prioritization of potential locations for harnessing wind energy to produce hydrogen in Afghanistan

Due to the devastating ecological effects and constrained reserves of fossil fuels, renewable energies are now globally accepted as viable alternative sources of energy. Among renewable energy sources, wind energy has become globally popular, primarily because wind farms can be rapidly built and easily maintained at a relatively low cost. Wind-powered hydrogen production is an effective solution for storing the excess energy output of wind farms. The hydrogen produced in this way can be used not only in fuel cells but also in cooling, oil, gas, and petrochemical fields. As a country devastated by war and instability, Afghanistan has major energy generation challenges and a substantially large power supply deficiency. However, there are good wind energy potentials in several parts of this country. There are also several hydrogen-consuming fields in Afghanistan that can benefit from hydrogen production from wind energy. This paper endeavored to distinguish the appropriate areas in Afghanistan for harvesting wind energy for hydrogen production using multi-criteria decision-making techniques. Eleven criteria were utilized to prioritize 20 Afghan provinces with wind energy potential. The Step-wise Weight Assessment Ratio Analysis (SWARA) was utilized to weight the criteria and Evaluation based on Distance from Average Solution (EDAS) were utilized to prioritize the provinces. Then, ARAS, TOPSIS, and VIKOR methods were used to validate the resultants. For criteria weighting with SWARA, “wind speed”, “wind power density” and “area of windy regions” with weights of 0.1423, 0.1356, and 0.1221 were introduced as the most significant criteria for this ranking. In all the rankings, Herat, Farah, and Jowzjan were identified as the top three most suitable provinces for wind power generation. The power output and hydrogen output to be achieved in Herat province using a 900-kW turbine were estimated to 2558.4 MW per year and 41.4 tons per year, respectively.     

Hydrogen from biomass – Present scenario and future prospects

Hydrogen is considered in many countries to be an important alternative energy vector and a bridge to a sustainable energy future. Hydrogen is not an energy source. It is not primary energy existing freely in nature. Hydrogen is a secondary form of energy that has to be manufactured like electricity. It is an energy carrier. Hydrogen can be produced from a wide variety of primary energy sources and different production technologies. About half of all the hydrogen as currently produced is obtained from thermo catalytic and gasification processes using natural gas as a starting material, heavy oils and naphtha make up the next largest source, followed by coal. Currently, much research has been focused on sustainable and environmental friendly energy from biomass to replace conventional fossil fuels. Biomass can be considered as the best option and has the largest potential, which meets energy requirements and could insure fuel supply in the future. Biomass and biomass-derived fuels can be used to produce hydrogen sustainably. Biomass gasification offers the earliest and most economical route for the production of renewable hydrogen.     

The sustainability of green hydrogen: An uncertain proposition

Green hydrogen is increasingly considered a vital element for the long-term decarbonization of the global energy system. For regions with scarce land resources, this means importing significant volumes of green hydrogen from regions with abundance of renewable energy. In producing countries, this raises significant sustainability questions related to production and export. To assess these sustainability-related opportunities and challenges, the authors first present a review of renewable energy deployment in the electricity sector, and then extend it to the foreseeable opportunities and risks of green hydrogen production in exporting countries. The paper finds that questions of freshwater and land availability are critical from an environmental and a socio-economic point of view, and that the development of international standards for the governance of hydrogen-related projects will be crucial. These should also address potential conflicts between the deployment of renewable energy for the decarbonization of local power grids, and the export of green hydrogen.     

Political,economic and environmental impacts of biomass-based hydrogen

The purpose of this study is to assess the political, economic and environmental impacts of producing hydrogen from biomass. Hydrogen is a promising renewable fuel for transportation and domestic applications. Hydrogen is a secondary form of energy that has to be manufactured like electricity. The promise of hydrogen as an energy carrier that can provide pollution-free, carbon-free power and fuels for buildings, industry, and transport makes it a potentially critical player in our energy future. Currently, most hydrogen is derived from non-renewable resources by steam reforming in which fossil fuels, primarily natural gas, but could in principle be generated from renewable resources such as biomass by gasification. Hydrogen production from fossil fuels is not renewable and produces at least the same amount of CO₂ as the direct combustion of the fossil fuel. The production of hydrogen from biomass has several advantages compared to that of fossil fuels. The major problem in utilization of hydrogen gas as a fuel is its unavailability in nature and the need for inexpensive production methods. Hydrogen production using steam reforming methane is the most economical method among the current commercial processes. These processes use non-renewable energy sources to produce hydrogen and are not sustainable. It is believed that in the future biomass can become an important sustainable source of hydrogen. Several studies have shown that the cost of producing hydrogen from biomass is strongly dependent on the cost of the feedstock. Biomass, in particular, could be a low-cost option for some countries. Therefore, a cost-effective energy-production process could be achieved in which agricultural wastes and various other biomasses are recycled to produce hydrogen economically. Policy interest in moving towards a hydrogen-based economy is rising, largely because converting hydrogen into useable energy can be more efficient than fossil fuels and has the virtue of only producing water as the by-product of the process. Achieving large-scale changes to develop a sustained hydrogen economy requires a large amount of planning and cooperation at national and international alike levels.     

A review of hydrogen production via biomass gasification and its prospect in Bangladesh

Hydrogen has been using as one of the green fuel along with conventional fossil fuels which has enormous prospect. A new dimension of hydrogen energy technology can reduce the dependency on non-renewable energy sources due to the rapid depletion of fossil fuels. Hydrogen production via Biomass (Municipal solid waste, Agricultural waste and forest residue) gasification is one of the promising and economic technologies. The study highlights the hydrogen production potential from biomass through gasification technology and review the parameters effect of hydrogen production such as temperature, pressure, biomass and agent ratio, equivalence ratios, bed material, gasifying agents and catalysts effect. The study also covers the all associated steps of hydrogen separation and purification, WGS reaction, cleaning and drying, membrane separation and pressure swing adsorption (PSA). To meet the huge and rising energy demand, many countries made a multidimensional power development plan by adding different renewable, nuclear and fossil fuel sources. A large amount of biomass (total biomass production in Bangladesh is 47.71 million ton coal equivalent where 37.16, 3.49 and 7.04 MTCE are agricultural, MSW and forest residue based biomass respectively by 2016) is produced from daily uses by a big number of populations in a country. It also includes total feature of biomass gasification plant in Bangladesh.     

Renewislands—Renewable energy solutions for islands

Increase of the global energy demand and environmental problems relating to fossil energy utilization request the new energy sources to replace the traditional fossil fuels. With respect to energy production, most of the islands in European Union and in the other parts of the world, depend on importation, mainly from oil and its related products. The global development of renewable energy technologies can assure sustainable supply of power for islands. To overcome the limitation of the sources of renewable energy, hydrogen is utilized as a storage medium integrated with intermittent renewable energy sources such as wind and solar. This paper introduces the programme of “Renewislands—Renewable Energy Solutions for Islands”, the work tasks, details of the design of the activities to develop solutions integrating intermittent renewable energy supply (RES), fuel cell (FC) and hydrogen infrastructure to promote RES and innovative decentralized power systems penetration in islands; main results achieved in each work packages are presented; in addition, the development of intermittent renewable energy penetration in specific European Islands are reviewed briefly.     

A figure of merit assessment of the routes to hydrogen

The efficient use of primary energy sources, which can be used for hydrogen production, is addressed by a consideration of four key measures, which reflect the ability of different sources and processing routes to meet underlying needs and the practical demands of energy on a large scale. The measures considered are carbon dioxide emission reduction, primary energy availability, land use implications and hydrogen production costs. Fourteen pathways to hydrogen are considered involving fossil fuels and nuclear energy as well as the range of renewable sources, and including additional strategies for carbon sequestration.The overall comparison of routes, based on simple figures-of-merit, shows a clear division between those using renewable energies and those associated with the traditional ‘high energy density’ primary sources. Emerging from the work is a clearer view of the implications of following a particular production path, the limitations of certain technologies and the research challenges which must be met in addressing future fuel options and global warming.     

Renewable energy market conditions and barriers in Turkey

Decentralized wind, hydropower, biogas and biomass, geothermal, solar thermal and solar electricity energy systems are the most commonly found renewable energy technologies promoted for rural energy supply within sustainable developments programs. They are, therefore, seen to have a central place in the practice of sustainable development and in allowing less development countries to bypass the environmentally damaging fossil fuel intensive paths made by industrialized countries. On the political front, many less development countries are critical of pressure on them to adopt environmental energy technologies.Turkey is situated the meeting point of three continents (Asia, Europe and Africa) and stands as a bridge between Asia and Europe. The country is located in southeastern Europe and southwestern Asia. As Turkey’s economy has expanded in recent years, the consumption of primary energy has increased. Presently in order to increase the energy production from domestic energy resources, decrease the use of fossil fuels as well as reduce of green house gas emissions different renewable energy sources are used for energy production in Turkey. The share of energy production from renewable energy sources has increased during the last 10 years. Turkey must import most of the energy to meet her needs. Turkey also has a large potential for renewable energies. The lack of knowledge about renewable energy technologies by most policy-makers, potential consumers, and energy firm managers has played against renewable energy developments. The paper presents renewable energy used in Turkey and Europe Union and evaluation of the market conditions and barriers of renewable energy use in Turkey.     

A snapshot of geothermal energy potential and utilization in Turkey

Turkey is one of the countries with significant potential in geothermal energy. It is estimated that if Turkey utilizes all of her geothermal potential, she can meet 14% of her total energy need (heat and electricity) from geothermal sources. Therefore, today geothermal energy is an attractive option in Turkey to replace fossil fuels. Besides, increase in negative effects of fossil fuels on the environment has forced many countries, including Turkey, to use renewable energy sources. Also, Turkey is an energy importing country; more than two-thirds of her energy requirement is supplied by imports. In this context, geothermal energy appears to be one of the most efficient and effective solutions for sustainable energy development and environmental pollution prevention in Turkey. Since geothermal energy will be used more and more in the future, its current potential, usage, and assessment in Turkey is the focus of the present study. The paper not only presents a review of the potential and utilization of the geothermal energy in Turkey but also provides some guidelines for policy makers.     

Life cycle cost analysis: A case study of hydrogen energy application on the Orkney Islands

Hydrogen can compensate for the intermittent nature of some renewable energy sources and encompass the options of supplying renewables to offset the use of fossil fuels. The integrating of hydrogen application into the energy system will change the current energy market. Therefore, this paper deploys the life cycle cost analysis of hydrogen production by polymer electrolyte membrane (PEM) electrolysis and applications for electricity and mobility purposes. The hydrogen production process includes electricity generated from wind turbines, PEM electrolyser, hydrogen compression, storage, and distribution by H₂ truck and tube trailer. The hydrogen application process includes PEM fuel cell stacks generating electricity, a H₂ refuelling station supplying hydrogen, and range extender fuel cell electric vehicles (RE-FCEVs). The cost analysis is conducted from a demonstration project of green hydrogen on a remote archipelago. The methodology of life cycle cost is employed to conduct the cost of hydrogen production and application. Five scenarios are developed to compare the cost of hydrogen applications with the conventional energy sources considering CO₂ emission cost. The comparisons show the cost of using hydrogen for energy purposes is still higher than the cost of using fossil fuels. The largest contributor of the cost is the electricity consumption. In the sensitivity analysis, policy supports such as feed-in tariff (FITs) could bring completive of hydrogen with fossil fuels in current energy market.     

“Green” path from fossil-based to hydrogen economy: An overview of carbon-neutral technologies

While the dominant role of hydrogen in a sustainable energy future is widely accepted, the strategies for the transition from fossil-based to hydrogen economy are still actively debated. This paper emphasizes the role of carbon-neutral technologies and fuels during the transition period. To satisfy the world's growing appetite for energy and keep our planet healthy, at least 10 TW (or terawatt) of carbon-free power has to be produced by mid-century. Three prominent options discussed in the literature include: decarbonization of fossil energy, nuclear energy and renewable energy sources. These options are analyzed in this paper with a special emphasis on the role of hydrogen as a carbon-free energy carrier. In particular, the authors compare various fossil decarbonization strategies and evaluate the potential of nuclear and renewable energy resources to meet the 10 TW target. An overview of state-of-the-art technologies for production of carbon-free energy carriers and transportation fuels, and the assessment of their commercial potential is provided. It is shown that neither of these three options alone could provide 10 TW of carbon-neutral power without major changes in the existing infrastructure, and/or technological breakthroughs in many areas, and/or a considerable environmental risk. The authors propose a scenario for the transition from current fossil-based to hydrogen economy that includes two key elements: (i) changing the fossil decarbonization strategy from one based on CO₂ sequestration to one that involves sequestration and/or utilization of solid carbon, and (ii) producing carbon-neutral synthetic fuels from bio-carbon and hydrogen generated from water using carbon-free sources (nuclear, solar, wind, geothermal). This strategy would allow taking advantage of the existing fuel infrastructure without an adverse environmental impact, and it would secure a smooth carbon-neutral transition from fossil-based to future hydrogen economy.     

Renewable energy options: What could developing countries expect from them?

In order to make a realistic assessment of the energy alternatives for the developing world, the present conditions of the developing region, consisting of Africa and Asia (excluding South Africa, Japan and China), are studied first. Highlights include: low commercial energy consumption (0.2 kW/cap), heavy dependence on oil and noncommercial energy, and especially poor conditions of the rural energy supply.Since fossil fuels need to be conserved and nuclear energy is not an option for many of the developing countries, what renewable options could bring is evaluated in detail. Socio-techno-economic parameters for developing and employing renewable energy sources are identified for biogas, wood plantation, solar, and hydropower. The study concludes that the developing countries could obtain 35% of the energy in 2030 with the low-demand scenario of 0.9 kW/cap. However, with the high-demand scenario of 1.4 kW/cap, active policies in nuclear energy and fossil fuels as well would be required.     

Utilization of green ammonia as a hydrogen energy carrier for decarbonization in spark ignition engines

Rising concerns about the dependence of modern energy systems on fossil fuels have raised the requirement for green alternate fuels to pave the roadmap for a sustainable energy future with a carbon-free economy. Massive expectations of hydrogen as an enabler for decarbonization of the energy sector are limited by the lack of required infrastructure, whose implementation is affected by the issues related to the storage and distribution of hydrogen energy. Ammonia is an effective hydrogen energy carrier with a well-established and mature infrastructure for long-distance transportation and distribution. The possibility for green ammonia production from renewable energy sources has made it a suitable green alternate fuel for the decarbonization of the automotive and power generation sectors. In this work, engine characteristics for ammonia combustion in spark ignition engines have been reported with a detailed note on engines fuelled with pure ammonia as well as blends of ammonia with gasoline, hydrogen, and methane. Higher auto-ignition temperature, low flammability, and lower flame speed of ammonia have a detrimental effect on engine characteristics, and it could be addressed either by incorporating engine modifications or by enhancing the fuel quality. Literature shows that the increase in compression ratio from 9.4:1 to 11.5:1 improved the maximum power by 59% and the addition of 10% hydrogen in supercharged conditions improved the indicated efficiency by 37%. Challenges and strategies for the utilization of ammonia as combustible fuel in engines are discussed by considering the need for technical advancements as well as social acceptance. Energy efficiency for green ammonia production is also discussed with a due note on techniques for direct synthesis of ammonia from air and water.     

Prospects and challenges of renewable hydrogen generation in Bangladesh

The collective endeavor in reaching net-zero emissions by 2050 and halting the impending effects of global warming has found a promising solution-hydrogen, a clean energy carrier with diversified applications. It is practical to transition H₂ production at scale from fossil fuels to renewable sources. The choice of appropriate hydrogen production route from renewables would regionally vary, depending on various factors. While a majority of the developed countries have kickstarted their transition towards a hydrogen economy, developing countries like Bangladesh have been lagging. This review explores the potential of a hydrogen-based energy system for Bangladesh - commencing with a technological comparison of existing production paths from renewable resources; then moving on to a preliminary analysis of its available resources and technology options. Finally, a roadmap toward a hydrogen economy is envisioned, as the foundation for further study and public policy initiatives aimed at hastening Bangladesh's transition to a carbon-free energy system.     

Life Cycle Assessment (LCA) for use on renewable sourced hydrogen fuel cell buses vs diesel engines buses in the city of Rosario,Argentina

The purpose of this paper is to build the first Energy and Life Cycle Analysis (LCA) comparison between buses with internal combustion engine currently used in the city of Rosario, Province of Santa Fe, Argentina, and some technological alternatives and their variants focusing on buses with an electrical engine powered by compressed hydrogen that feet fuel cells of polymer electrolyte membrane (PEM). This LCA comprehend raw material extraction up to its consumption as fuel. Specifically, hydrogen production considering different production processes from renewable sources called “green hydrogen” (Velazquez Abad and Dodds, 2020) [1] and non-renewable sources called “grey hydrogen” (Velazquez Abad and Dodds, 2020) [1]. Renewable sources for hydrogen production are rapid cut densified poplar energy plantation, post-industrial wood residues such as chips pallets, and maize silage. For non-renewable hydrogen production sources are the local electrical power grid from water electrolysis and natural gas from the steam methane reforming process.Buses whose fuel would be renewable hydrogen, produced near the City of Rosario, Province of Santa Fe, Argentina, meet one of the main criteria of sustainability biofuels of the European Union (EU) taken into account Renewable Energy Directive (RED) 2009/28 [2] and EU RED Directive 2018/2001 [3] that need significant reduction on net greenhouse gases (GHG) from biomass origin row material respect fossil fuels. At least 70% of GHG would be avoided from its main fossil counterpart of the intern combustion engine (ICE), in the worst and current scenario of the emission factor of the electrical grid of Argentina in the point of use that is about 0.40 kg CO_2eq/kWh with energy and environmental load of 100% in the allocation factor in the hydrogen production stage of the LCA analysis.     

Exergy analysis of renewable energy sources

Oil crises in the past years made more obvious the dependency of economies on fossil fuels. As a consequence, the need for new energy sources became more urgent. Renewable energy sources could provide a solution to the problem, as they are inexhaustible and have less adverse impacts on the environment than fossil fuels. Yet, renewable energy sources technology has not reached a high standard at which it can be considered competitive to fossil fuels. The present study deals with the exergy analysis of solar energy, wind power and geothermal energy. That is, the actual use of energy from the existing available energy is discussed. In addition, renewable energy sources are compared with the non-renewable energy sources on the basis of efficiency.