Argos Honduras revealed this week that it has been testing the injection of hydrogen into the kiln of its integrated Piedras Azules cement plant. It has completed a pilot with Portugal-based company UTIS. As part of the process it has been trialling, it has split water by electrolysis and then injected the hydrogen and oxygen directly into the kiln via the main burner. The pilot has reportedly increased clinker production and reduced petcoke consumption at the plant.

Argos is far from alone in using hydrogen in this way. At the end of August 2022 Cemex said that it was also starting to use hydrogen at its San Pedro de Macorís cement plant in the Dominican Republic. CRH UK-subsidiary Tarmac completed a trial in July 2022 using hydrogen as an alternative to natural gas at its Tunstead lime plant. HeidelbergCement UK-subsidiary Hanson also ran a successful trial using hydrogen as part of the fuel mix at its Ribblesdale cement plant in 2021. The government-funded trial used a combination of hydrogen (39%), meat and bone meal (12%) and glycerine (49%) to reach a 100% alternative fuels substitution rate. In 2021 Hanson reported that fuel switching to hydrogen could help it reduce its 2050 CO₂ emissions by about 3%, or by -35kg CO₂/t of cement product.

Cemex appears to be a leader in using hydrogen in this way. The Mexico-based company started injecting hydrogen in 2019 and retrofitted all of its European cement plants with the technology to do so in 2020. It then said it wanted to roll this out to the rest of its operations. The project in the Dominican Republic is an example of this. In February 2022 it announced an investment in HiiROC, a UK-based company that has developed a method using thermal plasma electrolysis to convert biomethane, flare gas, or natural gas into hydrogen. The stated aim of this investment was to increase Cemex's hydrogen injection capacity in its cement kilns and to increase its alternative fuel substitution rate. Back in 2020 Cemex said that it planned to use hydrogen injection to contribute 5% of its progress towards its 2030 CO₂ emissions reduction target along with other measures such as increasing its thermal substitution rate and reducing its clinker factor.

As can be seen above there are a number of examples of hydrogen injection being used in cement plants in Europe and the Americas. However, there is very little actual data available publicly at this stage on how much hydrogen that the plants are actually using. For example, Cemex may have hydrogen injection equipment installed at all of its plants in Europe but it is unclear how many plants are actually using it. This is understandable though, given how commercially sensitive the fuel mix of a cement plant is and in Cemex’s case if it wishes to maintain a leader’s advantage in using a new technology.

It is interesting to see, in what has been released so far, the focus on doing deals with companies that supply electrolysis technology such as HiiROC and UTIS. A feasibility study ahead of the Hanson trial at Ribblesdale by the MPA, Cinar and the VDZ suggested that upgrading a kiln burner and adding all the necessary hydrogen storage and pipework could cost at least Euro400,000. However, this study also pointed out that the cost of hydrogen made a big difference to the cost of the CO₂ saving from using it as an alternative fuel. Hence the focus on the technology partners. It will be interesting to see how many more hydrogen injection projects are announced in the coming months and years and, crucially, who is providing the technology to supply the hydrogen.

For more information on the use of hydrogen in cement production see the proceedings from the 15th Global CemFuels Conference & Exhibition where presentations on the topic were given by Cemex and the VDZ