The myth of hydrogen economy

January 10, 2022 09:38
Photo: Reuters

Elon Musk, Tesla CEO, once said that the idea of hydrogen fuel cell vehicles was "mind-boggling stupid", which has aroused much controversy.

Hydrogen is the most abundant element in the universe, for example, water (H2O) contains hydrogen. With the global trend of reducing carbon emissions in recent years, the hydrogen economy has become a hot topic. In the Ministry of Science and Technology’s 14th Five-Year Plan announced in 2021, hydrogen energy technology is one of the 18 key projects of China’s National Key R&D Programmes (NKPs). Different provinces and cities, including Beijing, Shanghai, Guangdong, Hebei, and Hubei, have successively released supporting policies for hydrogen energy planning.

According to the National Hydrogen Association (NHA) based in the United States, the National Aeronautics and Space Administration (NASA) currently uses the most liquid hydrogen worldwide, primarily for rocket propulsion. By the 1970s, the alarming oil crisis was pushing countries to explore alternatives, and the commercial potential of hydrogen fuel cells began to attract attention.

In theory, hydrogen can generate three times more energy than gasoline, it is a clean energy source that achieves zero carbon emissions. However, there is a joke in the energy industry: "Hydrogen is the fuel of the future, and it always will be.” The problem is that there is no natural source of hydrogen on Earth, most of it is combined with other molecules like those of fossil fuels, biomass, or water. The current hydrogen extraction technology is not cost-effective, hydrogen is difficult to capture directly and use, and the extraction process needs to consume more energy than obtainable from the resulting hydrogen.

At present, global hydrogen energy production can be divided by colour according to carbon emissions during its production:

• Grey & Black: Grey, if made from natural gas, or black, if made from coal.

• Blue: Made by technologies and materials as Grey and Black, with the carbon dioxide being separated out and stored away underground, known as carbon capture and storage (CCS).

• Green: Produced by electrolysis. According to the China Energy News, the cost of hydrogen produced by alkaline electrolysis in Mainland China is as high as RMB 35 per kg.

• Pink: Use nuclear energy in electrolysis.

• Turquoise: Heating methane until the hydrogen is separated out, leaving solid carbon behind.

As mentioned in a report released by the International Energy Agency in 2019, the current production of hydrogen energy is almost entirely from fossil fuels, with 6% from natural gas and 2% from coal. As a result, production of hydrogen is responsible for carbon emissions of around 830 million tonnes of carbon dioxide per year, equivalent to the total carbon emissions of the United Kingdom and Indonesia!

As the cost of renewable electricity continues to fall (electricity accounts for most of the cost of electrolytic hydrogen), and with the trend of falling prices and improved efficiency of related facilities such as electrolytes, the U.S. Department of Energy (DoE) announced the Hydrogen Shot in 2021, which seeks to reduce the cost of various clean hydrogen (i.e. except grey and black ones) by 80% to US$1 per kg within a decade.

Transportation accounts for up to 16% of global greenhouse gas emissions and causes many health problems. This makes people particularly eager for the fuel cell electric vehicles powered by hydrogen. One of the highlights of the Tokyo Olympics in Japan originally was the demonstration of hydrogen-powered vehicles. China is also ambitious in setting the goal to increase the number of the country’s hydrogen-powered fuel cell vehicles from less than 10,000 in 2021 to 100,000 by 2025.

The global hydrogen economy is still in the early stage of development, we need breakthroughs in developing new technologies in production, storage, and usage, while reducing costs at the same time. If China can achieve the goal of 100,000 hydrogen-powered fuel cell vehicles, it will definitely be a major milestone in global emissions reduction.

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Adjunct Professor, Department of Computer Science, Faculty of Engineering; Department of Geography, Faculty of Social Sciences; and Faculty of Architecture, The University of Hong Kong