As a way to resolve wind curtailment, the integration of hydrogen fuel at a wind farm allows flexibility to shift production to best match the resource availability with its particular operational needs and market factors.
As the world faces the environmental consequences of relying on traditional fossil fuels, people are turning to renewable energy sources. Amongst the renewable sources, wind power has been receiving a great deal of attention. As a free, clean, and inexhaustible energy source, it is one of the most promising methods to generate environmental-friendly energy . It also significantly reduces the dependence on fossil fuels and eliminates emissions of carbon dioxide and other harmful pollutants. However, the limitations of producing electricity from wind energy systems include: the dependence on the regularity of wind, storage and transport problems, and the need for converting the energy from wind turbines into a versatile energy carrier . Furthermore, wind curtailment, which is the reduction in electricity generation below the capability produced by a well-functioning wind turbine system, is another big issue that needs to be considered . In this case, hydrogen energy systems may provide the best solutions to many of the problems stated previously. Without releasing any pollutant gases, hydrogen produced from renewable energy sources such as wind, offers the promise of a clean and sustainable energy carrier due to its ability to store and deliver a tremendous amount of energy and has a great potential to be the “fuel of the future” [1,3]. Advantages of hydrogen include environmental safety, a high conversion efficiency, and a high energy density between 120 and 142 MJ per kg . This paper will review the basic principles and necessary requirements of a wind energy-hydrogen system and suggest future research in more undeveloped and developing nations, taking a study conducted in Afghanistan as an example.
The wind power hydrogen industry is currently developing toward the trend of intelligence and informationization, promoting the high-quality development of this industry . As a way to resolve wind curtailment, the integration of hydrogen fuel at a wind farm allows flexibility to shift production to best match the resource availability with its particular operational needs and market factors . The current hydrogen production system by wind power is “a clean and efficient mode of energy” that directly generates electricity through wind turbines or by the electrolysis of water to produce hydrogen in an electrolyzer . The basic structure of the wind energy-hydrogen system is illustrated in Figure 1.
Fig 1. Basic structure of wind energy-hydrogen system 
The key principles of the system presented in Figure 1 are that the hydrogen generated via electrolysis cannot be absorbed by the power grid as it goes to storage right away, and the electricity generated by the non-grid-connected wind power can generate hydrogen directly . The ratio of wind power into power grid and hydrogen production can be adjusted by the control system accordingly, whereby the initial energy lost through wind curtailment can be absorbed maximally . Even during times when there is insufficient wind, the grid connection can operate as back-up electricity to ensure the electrolyzer is functioning at full capacity . Moreover, on top of providing energy to the power grid, excess electric power supplied by the wind turbines can also result in the production of hydrogen through electrolysis of water instead of curtailing the electricity as is commonly done . The hydrogen is pressurized for storage and can be used in a wide range of applications such as hydrogen fuel cell vehicles or for electricity generation using a fuel cell system . The latter may be an alternative method suitable for small-scale energy generation in remote areas where wind is scarce . Further development of the hydrogen fuel cells can meet the needs of various population sizes and provide solutions for the power supply problems of several industries and residential housing . Even though wind energy constitutes a reliable option for hydrogen production with respect to the extensive benefits it brings about, the current scale of the hydrogen production system is typically only within a few megawatts of power, while the main centralized wind power system has reached a few hundred megawatts or more . Even though the storage density of hydrogen can be increased by pressure hydrogen storage technology or solid-state hydrogen storage technology, the capacity deficiency of the electrolysis hydrogen system is one of the main reasons for the differences in power generation, making it a major obstacle to the practical application of the system . For large-scale purposes, the hydrogen fuel cell also needs to undergo further upgrades to form a cell with a higher power density . Other issues include optimizing the electrolyzer during wind power fluctuations and developing a long-lasting fuel cell . With the goal of achieving high efficiency and low-cost, the rapid advancement of the technology for hydrogen production by wind power will lead to the further development of the equipment involved in the process.
Even though many key areas in wind power hydrogen production technology are to be improved, several technical requirements have been established to ensure an overall efficient operation of a wind-energy hydrogen system. The most important one being the adaptability of wind turbines to have strong resistance to wind fluctuations, since wind turbines contribute directly to powering the electrolyzer as well as the external power grid . Design characteristics of wind turbines, such as the size, vary according to their particular applications and area of use. A safety feature that protects wind turbines from damage is the cut-out speed . Cut-out speeds, typically above 25 km/h, refers to the wind speed at which wind turbines cease power generation . Another important requirement is building an electrolytic cell with the proper electrode, catalyst, and other parts to improve the conversion of high purity hydrogen . Lastly, the flexibility of the control system that brings together the hydrogen production technology and wind power is important to control the output distribution from the wind turbines to the electrolyzer for hydrogen production[1,2].
Other than the technical requirements mentioned above, the analysis of environmental and economic feasibility is necessary to verify that a site is favorable for wind power installations. Selecting the proper location to install wind turbines is the most important parameter to achieve economic viability . For an economy to reach a consensus to employ this system, additional precise evaluations are done to calculate the production, operation, and maintenance costs, as well as the payback period, the time when income exceeds costs and profitability is reached . Given that numerous developed countries have done research and assessed the competence of the hydrogen and wind energy system within various areas in their respective countries, undeveloped and developing nations are suffering from a lack of researchers’ attention . This lack of information encouraged a study of thorough economic evaluation of generating hydrogen using wind energy in Afghanistan in 2020 . By defining the exact specifications of the wind turbines such as nominal power and survival wind speed, accurate calculations can be done to investigate the possible electricity produced annually . The research collected data of some locations in Afghanistan with favorable wind speed and also considered some unpredictable circumstances that may degrade the ideal performance of the wind power plant. The study concluded that Fayzabad was found to be the best region for launching the wind-powered hydrogen production system, being the area with the average highest wind speed and that can generate up to approximately 260,601 kWh of electricity per year . Considering other scenarios and degradation rates, installing and utilizing the hybrid hydrogen-wind plant could be paid back in a period of 4-6 years. Despite the acute political and social problems undeveloped and developing countries such as Afghanistan are facing , this type of research helps to reach a goal of sustainable development.
The production of hydrogen by wind power not only provides an alternative for clean renewable energy with its great potential for a wide range of applications, but it also alleviates many existing problems of wind power generation such as the need for a storage and transport carrier and wind curtailment. Technical requirements such as the high adaptability of wind turbines, high efficiency of the electrolytic cell and the flexibility of the control system contribute to the overall efficiency of the system. Additionally, analysis of environmental and economic feasibility must be done to find and verify suitable sites for installation. However, the capacity deficiency of the electrolysis and optimizing the electrolyzer during wind power fluctuations are still main issues in the wind-power hydrogen system. More research also needs to be conducted in more undeveloped and developing nations such as Afghanistan to promote sustainable development. The continuous expansion of wind-power hydrogen production technology is of great significance to the future development and is an important strategic direction for the advances of renewable energy.
Dr. Raj Shah, Ms. Joceline Gan, Mr. Karthik Ladella | Koehler Instrument Company
Dr. Raj Shah is a Director at Koehler Instrument Company in New York, where he has worked for the last 25 years. He is an elected Fellow by his peers at IChemE, CMI, STLE, AIC, NLGI, INSTMC, The Energy Institute and The Royal Society of Chemistry An ASTM Eagle award recipient, Dr. Shah recently coedited the bestseller, “Fuels and Lubricants handbook”, details of which are available at
A Ph.D in Chemical Engineering from The Penn State University and a Fellow from The Chartered Management Institute, London, Dr. Shah is also a Chartered Scientist with the Science Council, a Chartered Petroleum Engineer with the Energy Institute and a Chartered Engineer with the Engineering council, UK. An adjunct professor at the Dept. of Material Science and Chemical Engineering at State University of New York, Stony Brook, Raj has over 350 publications and has been active in the alternative energy field for 3 decades. More information on Raj can be found at https://www.petro-online.com/news/fuel-for-thought/13/koehlerinstrument-company/dr-raj-shah-director-at-koehler-instrumentcompany-conferred-with-multifarious-accolades/53404
Ms. Joceline Gan, Mr. Karthik Ladella are part of a thriving internship program at Koehler Instrument company and students at State University of New York, Stony Brook, where Dr. Shah currently heads the External advisory board of directors at the Dept. of Chemical Engineering.
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