Review of Hydrogen Standards for China

Standards are essential to establish a market-receptive and safe environment for commercial hydrogen equipment and systems. A review of ISO, IEC and Chinese national hydrogen standards is presented in this paper. China has a larger number of hydrogen national standards than ISO and IEC, involving terminology, hydrogen fuel quality, hydrogen safety, construction, production and purification, storage, transportation and fuelling, applications, and testing. ISO hydrogen standards are mainly specialized in hydrogen fuel quality, safety, production, hydrogen fuelling station, and testing. IEC hydrogen standards are mainly specialized in fuel cell safety, applications and testing. Hydrogen standard system is now imbalanced and insufficient for China. We should pay much more attention on drafting standards for hydrogen production, storage, transportation and fuelling.


Introduction
Emissions from the energy and transport sectors are exacerbating climate change and reducing air quality. Hydrogen is one of only a few potential near-zero emission energy carrier, which has the potential to play a significant role in reducing GHG emission and improving air quality [1,2] . Hydrogen has garnered interest in recent years in applications of transportation and power, for example hydrogen fuel cell passenger cars, buses, trucks, trains, forklifts, ships, scooters, and stationary and portable fuel cell power systems [3] . Hydrogen fuel cell vehicles have been previously demonstrated in Olympic Games, World Expo, and Asian Games in China. Since 2017, hydrogen industry is booming in China. By the end of 2018, more than 25 cities have announced to support the deployment of hydrogen industry. The cumulative sales number of hydrogen fuel cell vehicles reached 3428. About 23 hydrogen fuelling stations are in operation. More 40 hydrogen fuelling stations are in construction and planning. Hydrogen fuel cell buses and trucks are in demonstration in Beijing, Foshan, Shanghai, Zhenghou, Yanchen, Yunfu, Zhangjiakou, etc [4,5] .
Standards provide technical definitions, guidelines, and instructions for design, manufacture, and testing. Standards also set minimum component or performance requirements. Standards are essential to establish a market-receptive and safe environment for commercial hydrogen equipment and systems.
International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) are the two key international standard development organizations. In China, Standardization Administration of the P. R. C. (SAC) undertakes unified management, supervision and overall coordination of standardization work in China. A review ISO, IEC and Chinese national hydrogen standards is presented and discussed in this paper. Organization of this paper is as follows: In session 2, hydrogen standard framework and technical committees are introduced.
In session 3, details and distribution of hydrogen standards for China are described and discussed.
In session 4, we summarize the main conclusions and provide some advices for hydrogen standardization work.

ISO technical committees
Technical Committee of Hydrogen Technologies (ISO/TC 197) is specialized in standardization in the field of systems and devices for the production, storage, transport, measurement and use of hydrogen. Subcommittee of Electrically Propelled Vehicles of Road Vehicles (ISO/TC 22/SC 37) is specialized in aspects of electrically propelled road vehicles, electric propulsion systems, related components and their vehicle integration.

IEC technical committees
Technical Committee of Fuel Cell Technologies (IEC/TC 105) is the main technical committee involving in drafting IEC hydrogen standards. IEC/TC 105 is specialized to develop standards of fuel cell technologies for all fuel cell (FC) types and various associated applications, including stationary FC power systems for distributed power generators and combined heat and power systems, FCs for transportation, auxiliary power units, portable FC power systems, micro FC power systems, etc.

Hydrogen standard framework for China
Hydrogen industry chain is complicated, involving production, storage, transportation, fuelling station, application, etc. Hydrogen standard framework is the guidance and base for hydrogen standardization work. In 2010, SAC/TC 309 established the hydrogen standard framework and prepared lists of standards in being and in planning for China. Hydrogen standard framework for China [6] As is shown in Figure 1, hydrogen standard framework consists of eight parts, including terminology, graphics and symbols; hydrogen fuel quality; safety; construction; production and purification; storage, transportation and fuelling; applications; and testing [7] . a) Terminology, graphics and symbols: This part includes standards of glossary, classification, symbols, naming specification, etc. b) Hydrogen fuel quality: This part includes standards of hydrogen specification for gaseous hydrogen, liquid hydrogen, HCNG, etc. c) Hydrogen safety: This part includes standards of safety in production, storage, transportation, fuelling, application, operation, etc. d) Hydrogen related construction: This part includes standards of design, construction, installation, and verification, etc. e) Hydrogen production: This part includes standards of various hydrogen production methods, including water electrolysis, purification of industrial gas, methanol reforming, steam reforming of natural gas, coal gasification, etc. f) Hydrogen storage, transportation and fuelling: This part includes standards of storage and transportation for gaseous hydrogen, liquid hydrogen, and hydrogen absorbed in reversible metal hydride. It also includes standards of hydrogen fuelling stations and its components. g) Hydrogen applications: This part includes standards for various applications of fuel cells, not only transportation, but also power generation, combined heat and power systems, etc. h) Testing: This part includes testing standards for hydrogen production, storage tanks and materials, performance of applications, safety, etc. Figure 2 shows the number of existing and effective national, ISO and IEC standards for hydrogen. China now has 93 national standards for hydrogen infrastructure and applications, which is much more than the number of ISO and IEC standards.

Summary
Terminology, graphics and symbols 3.62% Hydrogen fuel quality 5.80% Hydrogen safety 20.29% Hydrogen related construction 1.45% Hydrogen production and purification 5.80% Hydrogen storage, transportation and fuelling 12.32% Hydrogen applications 15.94% Testing 34.78% Fig. 6. Distribution of ISO, IEC and national hydrogen standards Figure 6 shows the distribution of ISO, IEC and national hydrogen standard. Amount of testing standards are more than the others. Amount of standards for hydrogen construction, production and purification, storage, transportation and fuelling are not adequate.

Conclusions
A review of ISO, IEC and Chinese national hydrogen standards is presented in this paper. Based on analysis and comparison, concluding remarks are as follows: (1) China has a larger number of hydrogen national standards than ISO and IEC, involving terminology, hydrogen fuel quality, hydrogen safety, construction, production and purification, storage, transportation and fuelling, applications, and testing.
(2) ISO hydrogen standards are mainly specialized in hydrogen fuel quality, safety, production, hydrogen fuelling station, and testing.
(3) IEC hydrogen standards are mainly specialized in fuel cell safety, applications and testing.
(4) Hydrogen standard system is imbalanced and insufficient for China. We should pay much more attention on drafting standards for hydrogen production, storage, transportation and fuelling.