[Kim Yong-joo Column] Hydrogen Fuel Cell Tractors: The State of Domestic and Global Patent and Technology Competition and the Urgency of Securing Domestic Technology

[Kim Yong-joo Column] Professor, Department of Smart Agriculture Systems and Mechanical Engineering, College of Agriculture and Life Sciences, Chungnam National University
 

Introduction — For Large Agricultural Machinery, the Shift to Eco-Friendly Power Sources Is Now Essential

As the farming population continues to decline and the area burden per person increases, mechanization in agricultural fields has developed with a focus on larger equipment. Large tractors exceeding 100 horsepower must perform high-load tasks such as plowing, rotary tilling, and towing large implements for long periods, making the stability and continuity of the power source more important than anything else. However, amid the recent global trend toward carbon neutrality, the introduction of eco-friendly power sources to replace diesel engines has emerged as an unavoidable task in the field of large agricultural machinery as well.

The question is which eco-friendly power source is suitable for large agricultural machinery. Electric batteries have established themselves as a strong alternative in passenger cars and small agricultural machinery, but their limitations are clear when applied directly to large tractors of 100 horsepower or more. Batteries have low energy density, meaning the amount of energy that can be stored relative to weight, so securing the energy needed for long-duration, high-load work makes the battery itself excessively heavy. In addition, placing batteries within the limited space allowed by tractor structures creates design problems. On top of that, charging times are long, creating practical constraints for continuous work during the busy farming season.

Hydrogen fuel cells are drawing attention as an alternative that can fundamentally overcome these limitations. Hydrogen fuel cells generate electricity through the electrochemical reaction of hydrogen and oxygen, making them a pollution-free power source that emits only water while also offering far superior energy density and shorter refueling times compared with batteries.

                        <Figure 1> Comparison of energy density per unit weight between lithium-ion batteries and compressed hydrogen

As can be seen from the comparison above, hydrogen fuel cells can store about four times more energy than lithium-ion batteries at the same weight. In other words, to store the same amount of energy, a battery must be much heavier than a hydrogen fuel cell. Tractors require a certain level of weight to secure high traction, but excessive weight increases soil compaction and driving resistance and can reduce energy efficiency and work efficiency.

        <Figure 2> Comparison of time by charging method for batteries and hydrogen fuel cells (based on 100 kWh)

Also, as shown in the figure above, because hydrogen is stored and refueled under high pressure in gaseous form, energy can be replenished in a short time, making it more advantageous than battery systems in actual agricultural work sites. When replenishing about 100kWh of energy, hydrogen can be refueled in about 3 to 5 minutes depending on refueling conditions and storage vessel specifications. By contrast, a battery using a 200kW-class fast charger may take about 30 to 40 minutes, while slow charging may take about 6 to 10 hours or more. Therefore, in agricultural work during the busy season when working time is limited or in operations requiring long continuous running, hydrogen systems that can reduce waiting time for refueling may have relatively high competitiveness in terms of equipment utilization and work efficiency.

                  <Figure 3> Power generation principle and flowchart of a hydrogen fuel cell (PEMFC) tractor

The figure above schematically illustrates the power generation principle of a hydrogen fuel cell tractor. Hydrogen stored in the hydrogen storage tank undergoes an electrochemical reaction inside the fuel cell stack together with oxygen taken in from the air to generate electricity, and this electricity is basically used to drive the vehicle. If the power produced by the fuel cell exceeds the vehicle's required output, the surplus power is stored in an auxiliary power source such as a high-voltage battery or supercapacitor. Conversely, if the vehicle's required output is greater than the fuel cell's generated output, the energy stored in the auxiliary power source is used together. Since only water and thermal energy are emitted after the reaction, this is a structure that can completely replace diesel engines while achieving zero emissions.

<Figure 4> Number of patent applications for hydrogen fuel cell agricultural tractors by major domestic and foreign companies (based on the five IP countries and PCT, publications and registrations disclosed before July 1, 2026)

Kubota of Japan in a League of Its Own — Preempting the Future Market Through Patents
The key issue is who secures this hydrogen fuel cell large tractor technology first. The company leading this competition is Kubota of Japan, the world's third-largest agricultural machinery company. At the 2025 Osaka-Kansai Expo, Kubota unveiled the world's first 100-horsepower-class autonomous hydrogen fuel cell tractor prototype. This tractor can operate continuously for nearly half a day on a single hydrogen refueling, and the refueling time is only about 10 minutes, making it a case that demonstrates the practical effectiveness of hydrogen fuel cells in the eco-friendly transition of large agricultural machinery.

An even more noteworthy aspect is Kubota's patent strategy. A comparison of the status of hydrogen fuel cell agricultural tractor-related patents held by major domestic and foreign companies in the agricultural tractor field (KUBOTA, YANMAR, ISEKI, Deere & Company, CNH) showed that Kubota holds a total of 171 patents, accounting for about 82% of the total and ranking overwhelmingly first. Meanwhile, the only group pursuing Kubota in this field was a Korean research team. These achievements were created by the industry-academia-research team for the 'Development of an Eco-Friendly Hydrogen Fuel Cell-Based 110kW-Class Large Tractor'¹ (19 cases, about 9%).

         <Figure 5> Number of annual patent applications for hydrogen fuel cell agricultural tractors by major domestic and foreign companies

Status of Domestic Technology — The Challenge of the Domestic Development Consortium and the Remaining Tasks
As examined earlier, since 2022 the domestic research team's average annual growth rate in patent applications has been 18.9%, only about one-fifth of Kubota's 98.3%. In addition, among the 19 patents disclosed domestically, only 7 PCT applications (about 37%) were filed to secure rights in overseas markets, showing that it falls far short of Kubota in terms of responsiveness to overseas markets as well. Still, there is also a hopeful aspect. While Kubota is concentrating on patents specialized in a structure that places hydrogen tanks on the upper part (roof) of the cabin on its tractor platform, the domestic research consortium is focusing on a structure that mounts hydrogen modules below the cabin driver's seat and above the powertrain. This can be evaluated as a point of technological differentiation in that it has secured both versatility that can be easily applied to any of the platforms of Korea's three tractor manufacturers and design technology that takes vehicle stability into account. 

Conclusion and Suggestions — To Avoid Missing the Golden Time
In summary, hydrogen fuel cells are a more realistic alternative than batteries for the eco-friendly transition of large agricultural machinery, and the technology competition has already begun. While Kubota, the world's third-largest agricultural machinery company, is accelerating patent applications based on overwhelming capital strength, in Korea an industry-academia-research team is, at least for now, the only one forming a competitive structure. However, it cannot be guaranteed that this structure will continue in the future.

The practical obstacles blocking the commercialization of hydrogen fuel cell tractors must also be clearly pointed out. Korea's hydrogen refueling infrastructure is still centered on passenger cars, and even that has been built along urban areas and major roads, making it difficult to find refueling infrastructure in rural regions. No matter how excellent a hydrogen fuel cell tractor is developed, if hydrogen cannot be easily refueled near farms, commercialization will inevitably be difficult.

First, with only the independent investment of research institutions and individual companies, it is difficult to keep up with the speed of technological development of leading overseas companies that are ahead in capital strength and market size. Even if initial development costs are high, continuous investment can increase the localization rate of core components and production scale, thereby stabilizing system prices in the long term. Just as electric vehicles and electric charging infrastructure overcame high initial costs and limited marketability to grow into an industry, hydrogen agricultural machinery must also secure economic feasibility and practicality through continuous technological development and market investment.

Second, to supply hydrogen stably in rural areas, it is necessary to build not only refueling infrastructure but also an eco-friendly agricultural energy ecosystem that organically links hydrogen production, transportation, storage, and refueling. In particular, unlike ordinary passenger cars, agricultural machinery is operated for long periods in rural areas and remote work sites where access to refueling stations is low, so existing fixed refueling stations alone are not sufficient to respond effectively to actual agricultural work demand. Therefore, it is necessary to develop and demonstrate various supply methods suited to regional and working conditions, such as mobile hydrogen refueling stations, on-site hydrogen production and refueling facilities, and dedicated charging systems for agricultural machinery. The hydrogen agricultural machinery industry must go beyond separately developing vehicles and refueling infrastructure and evolve into a sustainable eco-friendly agricultural energy ecosystem by linking the entire process from hydrogen production to supply and use at agricultural work sites into a single industrial system.

Third, in the hydrogen fuel cell agricultural machinery market, it is important not only to develop the technology first but also to secure rights to that technology as broadly as possible. Kubota is preparing for the future global market by filing many patents simultaneously in multiple countries through priority claims and family patent strategies. At present, domestic researchers still maintain technological potential in competition with leading overseas companies. If the research achievements secured so far are not connected to follow-up development and demonstration, patents, and industrialization, the competitive structure that has been built with difficulty could quickly collapse. 

Hydrogen fuel cell tractors, together with electric tractors, are expected to become a key pillar leading the future eco-friendly agricultural machinery market. Depending on which country takes hold of the technological leadership, the landscape of the global agricultural machinery industry could change over the coming decades. In the next article, I would like to examine in more concrete detail the core component technologies of hydrogen fuel cell tractors and domestic and international demonstration cases.