(Bloomberg) -- Chinese exports of used cooking oil to Singapore jumped to a record last month, likely due to more demand from Neste Oyj’s renewable fuel refinery.

Shipments of UCO rose to 48,832 tons in May, 18% more than April and almost double the amount from a year earlier, according to data from Chinese customs. 

The surge was mainly attributable to the Finnish company’s plant, which completed an expansion this year, said biofuel traders who asked not to be identified as they aren’t authorized to speak publicly. The facility is the world’s biggest renewable diesel refinery and largest producer of sustainable aviation fuel, according to Neste.

Demand for green diesel and jet fuel is increasing as governments and industries seek to de-carbonize. China exported a record 1.58 million tons of UCO in 2022, while shipments from Malaysia and Indonesia also climbed.

The jump in cargoes to Singapore come as Chinese biodiesel producers pledge to improve compliance and export standards after European rivals called for action to stem “potentially fraudulent” shipments. China’s sales of methyl ester, a feedstock for biodiesel that’s made from UCO, to Europe have jumped sharply, but there are claims the fuels may be being mixed and mislabeled.

Read More: Asia Floods Europe with Green Fuel Suspected to Be Fraudulent

China’s total exports of used cooking oil rose 9% in May from a month earlier to 151,428 tons, the customs data show. Shipments to the US climbed 46%. Sales to Singapore and the US accounted for over 70% of Chinese exports, while most of the rest went to Europe.

Most of the Chinese UCO exports to Singapore and the US would be used to produce hydrogenated vegetable oil, which is recognized as a second-generation biodiesel.

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