Design and operation of a future hydrogen supply chain: Multi-period model

Introducing hydrogen as the fuel of the future necessitates a comprehensive, widespread supply chain network that is capable of producing, distributing, storing, and dispensing hydrogen to end users. Most of the early attempts to design and model the future hydrogen supply chain (HSC) were either limited to examining an individual component of the supply chain or focused on a predetermined hydrogen pathway. In these studies, a simulation-based approach has commonly been adopted rather than using a mathematical programming-based approach. The work presented here is an extension of an early attempt to design and operate a deterministic, steady-state HSC network using a mathematical modelling approach. In this paper, however, the model is developed to consider the availability of energy sources (i.e. raw materials) and their logistics, as well as the variation of hydrogen demand over a long-term planning horizon leading to phased infrastructure development. The proposed model is formulated as a mixed-integer linear programming (MILP) and solved via a commercial software tool, GAMS. The results show that the optimal design of the future HSC network of Great Britain (GB) starts with small-size plant together with using the hydrogen currently produced by chemical processing plants. As demand grows, more plants of different sizes should be built to meet the demand. The hydrogen produced will be transported using liquid hydrogen trucks and stored in different sizes of storage facilities.     

Systematic planning to optimize investments in hydrogen infrastructure deployment

The introduction of hydrogen infrastructure and fuel cell vehicles (FCVs) to gradually replace gasoline internal combustion engine vehicles can provide environment and energy security benefits. The deployment of hydrogen fueling infrastructure to support the demonstration and commercialization of FCVs remains a critical barrier to transitioning to hydrogen as a transportation fuel. This study utilizes an engineering methodology referred to as the Spatially and Temporally Resolved Energy and Environment Tool (STREET) to demonstrate how systematic planning can optimize early investments in hydrogen infrastructure in a way that supports and encourages growth in the deployment of FCVs while ensuring that the associated environment and energy security benefits are fully realized. Specifically, a case study is performed for the City of Irvine, California – a target area for FCV deployment – to determine the optimized number and location of hydrogen fueling stations required to provide a bridge to FCV commercialization, the preferred rollout strategy for those stations, and the environmental impact associated with three near-term scenarios for hydrogen production and distribution associated with local and regional sources of hydrogen available to the City. Furthermore, because the State of California has adopted legislation imposing environmental standards for hydrogen production, results of the environmental impact assessment for hydrogen production and distribution scenarios are measured against the California standards. The results show that significantly fewer hydrogen fueling stations are required to provide comparable service to the existing gasoline infrastructure, and that key community statistics are needed to inform the preferred rollout strategy for the stations. Well-to-wheel (WTW) greenhouse gas (GHG) emissions, urban criteria pollutants, energy use, and water use associated with hydrogen and FCVs can be significantly reduced in comparison to the average parc of gasoline vehicles regardless of whether hydrogen is produced and distributed with an emphasis on conventional resources (e.g., natural gas), or on local, renewable resources. An emphasis on local renewable resources to produce hydrogen further reduces emissions, energy use, and water use associated with hydrogen and FCVs compared to an emphasis on conventional resources. All three hydrogen production and distribution scenarios considered in the study meet California's standards for well-to-wheel GHG emissions, and well-to-tank emissions of urban ROG and NO_X. Two of the three scenarios also meet California's standard that 33% of hydrogen must be produced from renewable feedstocks. Overall, systematic planning optimizes both the economic and environmental impact associated with the deployment of hydrogen infrastructure and FCVs.     

Simulation and optimization of a stand-alone power plant based on renewable energy sources

By using the optimization software tool HOMER, this project aims at the energetic and economical optimization of a RES-based stand-alone system, already installed at Leicestershire, UK. Based on local meteorological data, an optimization strategy has been developed to identify the most economical and efficient scenarios for the generation of electricity to cover the desirable load in annual basis. Furthermore, the environmental-friendly character of the system was highly concerned in terms of emissions reduction, therefore the capability of an off-grid system was also investigated. The simulations show that an off-grid project with zero emissions is feasible, presenting the additional advantage of minimal capital investment costs. Finally, it is found that grid connection corresponds to very high operational costs in a long term.     

A global survey of hydrogen energy research,development and policy

Several factors have led to growing interest in a hydrogen energy economy, especially for transportation. A successful transition to a major role for hydrogen will require much greater cost-effectiveness, fueling infrastructure, consumer acceptance, and a strategy for its basis in renewable energy feedstocks. Despite modest attention to the need for a sustainable hydrogen energy system in several countries, in most cases in the short to mid term hydrogen will be produced from fossil fuels. This paper surveys the global status of hydrogen energy research and development (R&D) and public policy, along with the likely energy mix for making it. The current state of hydrogen energy R&D among auto, energy and fuel-cell companies is also briefly reviewed. Just two major auto companies and two nations have specific targets and timetables for hydrogen fuel cells or vehicle production, although the EU also has an aggressive, less specific strategy. Iceland and Brazil are the only nations where renewable energy feedstocks are envisioned as the major or sole future source of hydrogen. None of these plans, however, are very certain. Thus, serious questions about the sustainability of a hydrogen economy can be raised.     

Wind energy and the hydrogen economy—review of the technology

The hydrogen economy is an inevitable energy system of the future where the available energy sources (preferably the renewable ones) will be used to generate hydrogen and electricity as energy carriers, which are capable of satisfying all the energy needs of human civilization. The transition to a hydrogen economy may have already begun. This paper presents a review of hydrogen energy technologies, namely technologies for hydrogen production, storage, distribution, and utilization. Possibilities for utilization of wind energy to generate hydrogen are discussed in parallel with possibilities to use hydrogen to enhance wind power competitiveness.     

Analysis of the wind energy market in Denmark and future interactions with an emerging hydrogen market

The transition from fossil fuels to renewable energy sources is critical to reduce future emissions and mitigate the consequences hereof. Yet, the expansion of renewable energy, especially the highly fluctuating production of wind energy, poses economic challenges to the existing energy system in Denmark. This paper investigates the economic feasibility of integrating a 250 kW, 500 kW, 750 kW and 1 MW water electrolysis system in the existing Danish energy market to exploit excessive off- and onshore wind energy for hydrogen production used as fuel for transportation purposes. In 2018, Danish wind turbines produced excess energy during 1238 h, which poses a capacity constraint as the electrolysis systems are limited to only produce hydrogen for 14% of the total available annual hours. This paper concludes that the net present value of each investment is negative as the fixed and variable production costs exceeds the generated revenues and it is therefore not economical feasible to invest in an electrolysis system with the purpose of only operating whenever excess off- and onshore wind energy is available.     

Advanced optimal planning for microgrid technologies including hydrogen and mobility at a real microgrid testbed

This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis, seasonal storage and fueling station for meeting the hydrogen fuel demand of fuel cell vehicles, busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation).     

South African hydrogen infrastructure (HySA infrastructure) for fuel cells and energy storage: Overview of a projects portfolio

The paper provides brief introduction to the National South African Program, branded HySA (Hydrogen South Africa) as well as discusses potential business cases for deployment of hydrogen and fuel cell technology in South Africa. This paper also describes some key activities in the area of hydrogen production and storage within HySA Infrastructure Center of Competence in South Africa. The content of this paper is based on the presentation given during the recent WHEC 2016 Congress in Zaragoza, Spain. More specifically, the discussion of activities at HySA Infrastructure Center of Competence in the paper includes hydrogen production and storage.     

Projecting full build-out environmental impacts and roll-out strategies associated with viable hydrogen fueling infrastructure strategies

A transition from gasoline internal combustion engine vehicles to hydrogen fuel cell electric vehicles (FCEVs) is likely to emerge as a major component of the strategy to meet future greenhouse gas reduction, air quality, fuel independence, and energy security goals. Advanced infrastructure planning can minimize the cost of hydrogen infrastructure while assuring that energy and environment benefits are achieved. This study presents a comprehensive advanced planning methodology for the deployment of hydrogen infrastructure, and applies the methodology to delineate fully built-out infrastructure strategies, assess the associated energy and environment impacts, facilitate the identification of an optimal infrastructure roll-out strategy, and identify the potential for renewable hydrogen feedstocks. The South Coast Air Basin of California, targeted by automobile manufacturers for the first regional commercial deployment of FCEVs, is the focus for the study. The following insights result from the application of the methodology:

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Compared to current gasoline stations, only 11%-14% of the number of hydrogen fueling stations can provide comparable accessibility to drivers in a targeted region.

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To meet reasonable capacity demand for hydrogen fueling, approximately 30% the number of hydrogen stations are required compared to current gasoline stations.

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Replacing gasoline vehicles with hydrogen FCEVs has the potential to (1) reduce the emission of greenhouse gases by more than 80%, reduce energy requirements by 42%, and virtually eliminate petroleum consumption from the passenger vehicle sector, and (2) significantly reduce urban concentrations of ozone and PM2.5.

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Existing sources of biomethane in the California South Coast Air Basin can provide up to 30% of the hydrogen fueling demand for a fully built-out hydrogen FCEV scenario.

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A step-wise transition of judiciously located existing gasoline stations to dispense and accommodate the increasing demand for hydrogen addresses proactively key infrastructure deployment challenges including a viable business model, zoning, permitting, and public acceptance.

     

Thermodynamic analysis of solar energy use for reforming fuels to hydrogen

In this paper, a method is proposed for reforming fuels to hydrogen using solar energy at distributed locations (industrial sites, residential and commercial buildings fed with natural gas, remote settlements supplied by propane etc). In order to harness solar energy a solar concentrator is used to generate high temperature heat to reform fuels to hydrogen. A typical fuel such as natural gas, propane, methanol, or an atypical fuel such as ammonia or urea can be transported to distributed locations via gas networks or other means. The thermodynamic analysis of the process shows the general reformation reactions for NH₃, CH₄ and C₃H₈ as the input fuel by comparison through operational fuel cost and CO₂ mitigation indices. Through a cost analysis, cost reduction indices show fuel-usage cost reductions of 10.5%, 22.1%, and 22.2% respectively for the reformation of ammonia, methane, and propane. CO₂ mitigation indices show fuel-usage CO₂ mitigations of 22.1% and 22.3% for methane and propane respectively, where ammonia reformation eliminates CO₂ emission at the fuel-usage stage. The option of reforming ammonia is examined in further detail as proposed cycles for solar energy capture are considered. A mismatch of specific heats from the solar dish is observed between incoming and outgoing streams, allowing a power production system to be included for a more complete energy capture. Further investigation revealed the most advantageous system with a direct expansion turbine being considered rather than an external power cycle such as Brayton or Rankine type cycles. Also, an energy efficiency of approximately 93% is achievable within the reformation cycle.     

Automation infrastructure and operation control strategy in a stand-alone power system based on renewable energy sources

The design of the automation system and the implemented operation control strategy in a stand-alone power system in Greece are fully analyzed in the present study. A photovoltaic array and three wind generators serve as the system main power sources and meet a predefined load demand. A lead-acid accumulator is used to compensate the inherent power fluctuations (excess or shortage) and to regulate the overall system operation, based on a developed power management strategy. Hydrogen is produced by using system excess power in a proton exchange membrane (PEM) electrolyzer and is further stored in pressurized cylinders for subsequent use in a PEM fuel cell in cases of power shortage. A diesel generator complements the integrated system and is employed only in emergency cases, such as subsystems failure. The performance of the automatic control system is evaluated through the real-time operation of the power system where data from the various subsystems are recorded and analyzed using a supervised data acquisition unit. Various network protocols were used to integrate the system devices into one central control system managing in this way to compensate for the differences between chemical and electrical subunits. One of the main advantages is the ability of process monitoring from distance where users can perform changes to system principal variables. Furthermore, the performance of the implemented power management strategy is evaluated through simulated scenarios by including a case study analysis on system abilities to meet higher than expected electrical load demands.     

Performance investigation of an integrated wind energy system for co-generation of power and hydrogen

In this paper, a wind turbine energy system is integrated with a hydrogen fuel cell and proton exchange membrane electrolyzer to provide electricity and heat to a community of households. Different cases for varying wind speeds are taken into consideration. Wind turbines meet the electricity demand when there is sufficient wind speed available. During high wind speeds, the excess electricity generated is supplied to the electrolyzer to produce hydrogen which is stored in a storage tank. It is later utilized in the fuel cell to provide electricity during periods of low wind speeds to overcome the shortage of electricity supply. The fuel cell operates during high demand conditions and provides electricity and heat for the residential application. The overall efficiency of the system is calculated at different wind speeds. The overall energy and exergy efficiencies at a wind speed 5 m/s are then found to be 20.2% and 21.2% respectively.     

Performance analysis and optimization of a hydrogen liquefaction system assisted by geothermal absorption precooling refrigeration cycle

The present paper deals with the hydrogen liquefaction with absorption precooling cycle assisted by geothermal water is modeled and analyzed. Uses geothermal heat in an absorption refrigeration process to precool the hydrogen gas is liquefied in a liquefaction cycle. High-temperature geothermal water using the absorption refrigeration cycle is used to decrease electricity work consumption in the gas liquefaction cycle. The thermoeconomic optimization procedure is applied using the genetic algorithm method to the hydrogen liquefaction system. The objective is to minimize the unit cost of hydrogen liquefaction of the composed system. Based on optimization calculations, hydrogen gas can be cooled down to ?30 °C in the precooling cycle. This allows the exergetic cost of hydrogen gas to be reduced to be 20.16 $/GJ (2.42 $/kg LH₂). The optimized exergetic cost of liquefied hydrogen is 4.905 $/GJ (1.349 $/kg LH₂), respectively.     

Electrolytic hydrogen based renewable energy system with oxygen recovery and re-utilization

The Hydrogen Research Institute (HRI) has developed a stand-alone renewable energy (RE) system based on energy storage in the form of hydrogen. When the input devices (wind generator and photovoltaic array) produce more energy than is required by the load, the excess energy is converted by an electrolyzer to electrolytic hydrogen, which is then stored after stages of compression, purification and filtration. Conversely, during a time of input energy deficit, this process is reversed and the hydrogen produced earlier is reconverted to electrical energy through a fuel cell. The oxygen which has been produced by the electrolyzer during the hydrogen production is also stored at high pressure, after having gone through a purification and drying process. This stored oxygen can be re-utilized as oxidant in place of compressed air in the fuel cell. The modifications of the electrolyzer for oxygen storage and re-utilization of it as oxidant for the fuel cell are presented. Furthermore, the HRI has designed and developed the control system with power conditioning devices for effective energy management and automatic operation of the RE system. The experimental results show that a reliable autonomous RE system can be realized for such seasonal energy sources, using stored hydrogen as the long-term energy buffer, and that utilizing the electrolyzer oxygen by-product as oxidant in the fuel cell increases system performance significantly.     

Intermittent renewable energy: The only future source of hydrogen?

In this paper we assess the feasibility of various future energy production pathways for hydrogen. We argue that neither nuclear energy, nor coal gasification with carbon collection and storage can provide sufficient climate-neutral energy to be probable routes to a hydrogen future. Their contributions are likely to be too little and too late to be of much help. Hydroelectricity, geothermal and biomass energy can all provide base-load power, but even combined have limited potential, and are not always climate-neutral in operation. On the other hand, the high-potential renewable energy (RE) sources, particularly wind and direct solar energy, are intermittent. Further, wind resources are poorly matched to the existing distribution of world population. Wind power's high potential compared with present electricity demand, high return on energy invested, intermittency, and mismatch with load centres all favour hydrogen conversion and transmission to load centres.     

Technology forecasting and patent strategy of hydrogen energy and fuel cell technologies

This study presents the technological S-curves that integrates the Bibliometric and patent analysis into the Logistic growth curve model for hydrogen energy and fuel cell technologies and identifies the optimal patent strategy for the fuel cell industry, including PEMFC, SOFC, and DMFC/DAFC. Empirical analysis is via an expert survey and Co-word analysis using the United States Patent and Trademark Office database to obtain useful data. Analytical results demonstrate that the S-curves is a highly effective means of quantifying how technology forecasting of cumulative publication patent number. Analytical results also indicate that technologies for generating and storing hydrogen have not yet reached technological maturity; thus, additional R&D funding is needed to accelerate the development of hydrogen technology. Conversely, fuel cell technologies have reached technological maturity, and related patent strategies include freedom to operate, licensing, and niche inventions. The proposed model can be applied to all high-technology cases, and particularly to new clean technologies. The study concludes by outlining the limitations of the proposed model and directions for further research.     

Key strategies of hydrogen energy systems for sustainability

Here we conduct a parametric study to investigate the effects of hydrogen energy utilization on the global stability and sustainability. In this regard, in order to derive the hydrogen energy based sustainability ratio, the green energy based sustainability ratio, as developed earlier, is modified to come up with a new parameter, namely “hydrogen energy utilization ratio through non-fossil fuels”. We take actual historical data from key sources to determine the role of hydrogen energy for sustainability and make some future projections as the road map for hydrogen economy. In addition, an illustrative example on the hydrogen energy based sustainability ratio is presented by considering green energy sources such as solar, wind, hydro and nuclear to make hydrogen economy more environmentally benign and sustainable. It is found that hydrogen energy based global stability and sustainability ratios increase with the rise of hydrogen energy utilization ratio. The best results for hydrogen energy based sustainability ratio are obtained for the highest hydrogen energy impact ratios between 73.33% and 100%. In case of 10% of hydrogen energy utilization ratio, hydrogen based sustainability ratios for year 2010 are, respectively, determined to be 0.21%, 0.23%, 0.25%, 0.27% and 0.29% in 2.92% of hydrogen based global stability ratio by depending on the hydrogen energy impact ratios (=73.33%$=73.33\%$, 80%, 86.67%, 93.33% and 100%). In case of 20% of hydrogen energy utilization ratio, the hydrogen energy based sustainability ratios are found to be 1.09%, 1.19%, 1.28%, 1.38% and 1.48% in 7.41%, respectively. The results are really encouraging in a way that hydrogen economy appears to be one of the most significant players for better sustainability.     

Re-envisioning the role of hydrogen in a sustainable energy economy

This paper addresses the fundamental question of where hydrogen might fit into a global sustainable energy strategy for the 21st century that confronts the three-pronged challenge of irreversible climate change, uncertain oil supply, and rising pollution. We re-envision the role of hydrogen at national and international strategic levels, relying entirely on renewable energy and energy efficiency. It is suggested the time for an exclusive ‘hydrogen economy’ has passed, since electricity and batteries would be used extensively as well. Yet hydrogen would still play a crucial role: in road and rail vehicles requiring a range comparable to today’s petrol and diesel vehicles; in coastal and international shipping; in air transport; and for longer-term seasonal storage on electricity grids relying mainly on renewables. Hydrogen fuel cell vehicles are proposed where medium and long distance trips are required, with plug-in battery electric vehicles reserved for just short trips. A hierarchy of spatially-distributed hydrogen production, storage and distribution centers relying on local renewable energy sources and feedstocks would be created to limit the required hydrogen pipeline network to the main metropolitan areas and regions by complementary use of electricity as a major energy vector. Bulk hydrogen storage would provide the strategic energy reserve to guarantee national and global energy security in a world relying increasingly on renewable energy. It is recommended that this vision next be applied to specific countries by conducting detailed energy-economic-environmental modeling to quantify its net benefits.     

Overview of US patents for energy management of renewable energy systems with hydrogen

The problems of energy shortage, severe pollution, and global warming are becoming increasingly severe. Renewable energy systems with hydrogen have been widely used. In recent years, much literature has described the energy management of renewable energy systems with hydrogen in a comprehensive way. However, most of them are proposed and discussed from an academic point of view. There are likewise several different approaches and ideas in the patents that address the energy management of hydrogen renewable energy systems. Moreover, most patents are oriented toward industrial applications and still need to be reviewed and analyzed. To fill this gap, this paper reviews relevant US patents to find potential and industrial hydrogen applications and energy management strategies in renewable energy systems. The work presented in this paper will provide solutions and guidance in solving energy management problems in renewable energy systems.     

Modeling and optimization of an energy generation island based on renewable technologies and hydrogen storage systems

The widespread use of renewable energy sources is hindered by their intermittent and unpredictable nature. This problem can be overcome with a storage system which manages the time mismatch between energy production and load requirements.