Green hydrogen

Hydrogen is the subject of a renewed global enthusiasm: its current and future uses could avoid the use of fossil fuels in several sectors.

And since it is possible to obtain “green” hydrogen with low-emission production techniques, hydrogen could play a key role in the global energy transition by 2050.

On May 25, 2022, the Gouvernement du Québec unveiled the first Québec Green Hydrogen and Bioenergy Strategy.

There are different techniques for producing hydrogen. Depending on the process, the hydrogen obtained may be labelled as black, grey, blue, green, etc.

Yet hydrogen is odourless and colourless. Assigning a colour to hydrogen is a visual way of reflecting its origin, that is, the material and energy sources used in its production cycle.

Production from fossil fuels

Currently, 95% of the hydrogen consumed worldwide is produced from natural gas or coal.

Steam reforming of natural gas is the most common mode of production. It provides grey hydrogen from natural gas at a low cost.

It is also possible to convert coal into gas to produce brown hydrogen, from lignite, or black hydrogen, from anthracite. 

These processes rely on the transformation of fossil fuels and generate significant amounts of greenhouse gases. The production of 1 kg of hydrogen from natural gas emits 9 kg of carbon dioxide (CO₂).

If steps are added to the production cycle to capture and store the emitted CO₂, the resulting hydrogen will be labelled blue hydrogen.

Green hydrogen production

Green hydrogen can be produced by “water electrolysis”, whereby an electric current is passed through water to break down its molecules (H₂O) and extract hydrogen. In addition, if the current comes from a renewable energy source (hydroelectricity, wind or solar power), all elements of the generation cycle are low-carbon. This production technique generates very little greenhouse gas emissions.The produced hydrogen is labelled as green hydrogen. 

Green hydrogen accounts for about 2% of global production. Its production costs are currently higher than those of grey hydrogen.

Green hydrogen can also be produced from biomass through gasification. The process involves heating the biomass at very high temperatures to extract synthetic gas and eventually hydrogen.

Hydrogen can be used in very diverse sectors of activity.

Hydrogen has been used in various industrial processes for many years:

• in steel production;
• in petroleum refining;
• in the production of ammonia and fertilizers;
• in high-temperature processes such as glass production.

Most industries currently use hydrogen produced from natural gas or coal. Using green hydrogen would allow these companies to reduce their GHG emissions and improve their energy balance.

In the transportation sector, the use of hydrogen is still emerging. Two approaches are currently being explored:

• using fuel cell electric vehicles powered by hydrogen;
• replacing fossil fuels with synthetic fuels produced with hydrogen.

Fuel cell electric vehicles

In fuel cell electric vehicles, hydrogen plays the role of fuel to generate electricity on demand. The reaction of hydrogen and oxygen releases energy, recovered in the form of electricity and heat.

The development of fuel cell vehicles varies by sector:

• Light-duty vehicles: Some electric vehicle models, equipped with fuel cells, have been marketed primarily in Asia; their market share remains low to date.
• Heavy-duty vehicles: Hydrogen is being considered to decarbonize the freight transportation sector, particularly for long-haul trucking. Fuel cells will provide long range with minimal recharge time.
• Marine, rail and air transportation: Work is underway in different countries to commercialize sustainable and competitive solutions. For example, a hydrogen passenger train has been in service in Germany since 2018, and other European countries have followed suit in similar projects. A zero-emission aircraft project is also undergoing intense technological research.

Synthetic fuel production

To run a thermal engine, it is possible to replace, in whole or in part, the fossil fuel consumption with a synthetic fuel produced with green hydrogen. GHG emissions from a vehicle are then reduced based on the amount of synthetic fuel used.

Examples of synthetic green hydrogen fuels: 

• synthetic ammonia and methanol, used in marine transportation
• synthetic kerosene, used in air transportation
• synthetic gasoline and diesel, used in road transportation

Green hydrogen represents a promising solution to help the petrochemical industry increase its supply of synthetic fuels. The transportation sector can take advantage of these green fuels and find sustainable solutions to reduce its GHG emissions in the long term.

Hydrogen can also be combined with carbon dioxide captured from industrial emissions to produce syngas, an alternative to fossil-based natural gas.

Hydrogen can also be used to store electricity. It is temporarily stored and used when there is a greater need for an electricity supply.

Here are some examples of possible uses:

• Store energy for use in areas not connected to the power grid. For example, mining sites in northern Québec are producing electricity using diesel, a polluting energy source. They could use green hydrogen to generate electricity.
• Store energy to support electricity generation from solar panels or wind farms. These facilities provide varying amounts of energy depending on the weather. Excess electricity produced when demand is low could be used to produce hydrogen. During peak periods, hydrogen would be converted into electricity using a fuel cell. Solar and wind power generation could then better respond to changes in consumption.

Other uses of green hydrogen may be developed in the coming years.

With new technologies and clear standards, hydrogen could be injected directly into the natural gas system, taking advantage of the existing distribution system.

Technical report on hydrogen uses.