How best to produce it
Renewable or green hydrogen is produced through water electrolysis using electricity from renewable sources. The lower the cost of the electricity and the electrolysers, and the higher the utilisation rates, the more competitive the production costs become. This question of commercial viability is one of the dimensions Petrofac considered when it completed a front-end engineering design (FEED) study for the Arrowsmith project for Infinite Green Energy in Australia – a 25-tonne-per-day green hydrogen facility containing 60 MW of electrolysers.
In this regard, the Gulf, with its abundant sunshine and low cost of solar-generated power, has a clear advantage. Even so, it is often necessary to find alternative energy sources to step in at nighttime to maximise utilisation and optimise production costs. Again, the Gulf is in a formidable position, as it can deploy its gas assets to generate low-carbon or blue hydrogen through methane reforming, then capture the CO2 emissions and store in facilities like ADNOC’s mighty Al Reyadah project.
Although plenty of low-carbon hydrogen can be generated in this way, exporting it is another matter.
How best to export it
The hydrogen molecule is minuscule yet occupies a much larger volume than other energy vectors (for example, an equivalent volume of methane holds more than three times as much energy). And these twin attributes – of minute molecules and large volumes – present real challenges.
Although the export of liquefied hydrogen is an option, the amount of energy involved means it is around twice as efficient to export LNG and convert it to blue hydrogen at its destination. Therefore, other hydrogen carriers are required for efficient export.
One option is to turn to existing supply chains and export the hydrogen in the form of green ammonia, and we have delivered engineering studies for projects in Egypt and Chile. Another promising hydrogen carrier is methanol, which also utilises existing supply chains but avoids the toxicity challenge of ammonia. Here, the challenge is to obtain enough biogenic CO2 or non-fossil fuel CO2 to react with the green hydrogen to produce methanol, and, again, we have direct experience in engineering two projects in Southern Europe. Other potential technologies, like liquid organic hydrogen carriers (LOHCs) and metal hydrides, are being developed. However, it is the final uses of hydrogen that should dictate the carrier.