From kitchen waste to sky-high costs: inside Hong Kong’s quest for green jet fuel

China’s once-notorious “gutter oil”, recycled from kitchen and drainage waste, has almost vanished from dining tables in recent years and now carries the nickname liquid gold.

The substance has become a highly sought-after feedstock for producing clean energy, especially sustainable aviation fuel (SAF), with biofuel producers such as Hong Kong-based Ecoceres sourcing gutter oil across the Greater Bay Area.

EcoCeres’ co-chairman, Alan Chan Ying-lung, witnessed how the restaurant waste transformed from a nationwide food safety concern into a valuable commodity.

“I can recall that the gutter oil we collected was basically free 10 years ago, and authorities even offered subsidies [to collectors], but now the unit cost is even more expensive than fuel,” he said.