The crown prince of Abu Dhabi has thrown his weight behind a huge but uncertain hydrogen project in Texas, offering to buy 35 per cent of ExxonMobil’s plant in Baytown, Houston.

Sheikh Khaled bin Mohammed bin Zayed al-Nahyan, the son of the ruler of the United Arab Emirates, took part in the signing of a “multibillion-dollar” deal on Wednesday between Adnoc, Abu Dhabi’s state oil company, and Exxon.

Michele Fiorentino, executive vice-president of Adnoc’s low-carbon solutions, said the Baytown project was both “the largest, and most importantly, one of the most cost-competitive” attempts to make hydrogen without releasing large quantities of carbon dioxide. He said Adnoc’s investment was “very material, easily at the multibillion-dollar scale”.