Hydrogen energy is an important secondary energy for the clean transformation of the future energy system. In this paper, we first investigate the research, development, and implementation strategy of hydrogen energy in the USA, EU, and Japan. With the advantages of hydrogen energy and the future task of global carbon emissions reduction, we then analyze the key technologies research, industrial development, and transportation industry application on hydrogen energy. The promotion strategies of hydrogen energy technologies in the USA, EU, and Japan are compared from the technical point of view. And the gap in hydrogen energy technologies between China and the countries was pointed out. Based on the actual statistical data, the carbon emissions of railway, highway, water, and air transportation in China are analyzed. With the characteristic parameters of hydrogen energy, the effect of hydrogen energy application on carbon emission reduction is calculated in different fields, such as road and railway. The results show that the carbon emissions are reduced by 70 million tons if the hydrogen energy can reach 10% in energy consumption of road freight transportation, using 10 million tons of hydrogen could reduce nearly 100 million tons of carbon emissions. We propose the research and application strategy of hydrogen energy and establish the comprehensive complementary regulation mechanism of renewable energy and hydrogen energy. For example, the abandoned electricity of renewable power generation in western China can be used recently to reduce the cost of hydrogen production from electrolytic water, gray hydrogen can be used to replace fuel oil, and the market of the hydrogen fuel cell can be expanded in the medium and long term. We also study the key fields which are suitable for hydrogen energy development in the transportation industry. The analysis shows that if the application of hydrogen energy in road transportation can reach 40 million tons in 2060, it is expected to achieve a carbon emission reduction of about 400 million tons in the transportation industry. Under the goal of the carbon neutrality, we propose suggestions of promoting hydrogen energy technology and products in passenger and freight transportation of high-power, long-distance, and low-temperature areas and building a green transportation system together with the existing development strategy of electric vehicles. Copyright © 2021 by Science Press.
