Hydrogen energy is the chemical energy of hydrogen, that is, the energy released by the element hydrogen during physical and chemical changes. Hydrogen and oxygen can be burned to produce heat or converted into electricity using fuel cells. Hydrogen energy is currently categorized by color into grey, blue and green hydrogen(see descriptions below), depending on how it is produced and its carbon footprint.

❖ Grey hydrogen

Grey hydrogen is produced through the conversion reaction of fossil fuels (natural gas, coal, etc.). It is also the most common form of hydrogen production today due to its low production costs and mature technology. It

is called grey hydrogen because it releases a certain amount of carbon

dioxide during the hydrogen production process and is therefore not completely carbon-free and green.

❖ Blue hydrogen

Technologies such as carbon capture and storage are applied to grey hydrogen to retain carbon rather than emitting it into the atmosphere. Blue hydrogen production, as a transitional technical method, will accelerate the development of a green hydrogen society.

❖ Green hydrogen

Green hydrogen is produced by using renewable energy sources such as solar and wind power to electrolyze water in a manner that results in essentially no greenhouse gas emissions, which is why it is called “zero carbon hydrogen.” Green hydrogen is the ideal form of hydrogen energy, but at present the technical threshold and high costs mean that it will take time to achieve large-scale application.

Globally, approximately 70 million tons of hydrogen energy is produced annually, primarily from fossil fuels. As the global low-carbon transition accelerates, hydrogen energy, especially clean hydrogen energy, will develop rapidly. According to forecasts by the major international energy agencies, hydrogen energy production will reach 500-800 million tons annually by 2050 (see Figure 1). By this point, hydrogen energy that is produced will mostly consist of clean hydrogen energy, represented by blue and green hydrogen. In terms of market share, hydrogen energy is expected to rise from a mere 0.1% of global energy at present to more than 12% by 2050s.

Pic.2 Forecasts of global hydrogen production by 2050 by major international energy agencies (in 100 million tons)

(the picture originates from Sources: Statista; KPMG analysis)

The article originates from Sources: Statista; KPMG analysis