The world’s largest oil firms may need to be careful relying on carbon capture and storage to reduce emissions from operations as much as they would like.

While almost every major oil and gas firm has said it would design facilities with CCS and use these technologies to cut the carbon footprint of their operations, U.S. oil supermajor Chevron has just had to admit that its massive CCS project at the Gorgon LNG facility in Australia has fallen short of the requirements to inject carbon dioxide (CO2) set by the Australian regulators.

Western Australian regulators approved the Gorgon LNG project, operated by Chevron, with Exxon and Shell holding 25 percent each as joint venture partners, with the requirement that at least 80 percent of reservoir CO2 is removed and injected.

Chevron, however, has injected only 30 percent of the CO2 due to continuous problems with the systems, Boiling Cold reported on Friday.

Chevron Australia managing director Mark Hatfield said on Monday that “while the system had delivered significant reductions in Gorgon’s emissions, the time taken to safely start the system meant Chevron had not met injection requirements.”

“Chevron is working with the WA regulator on making up the shortfall and will report publicly on that later in the year,” Hatfield said.

“Like any pioneering endeavour, it takes time to optimise a new system to ensure it performs reliably over 40-plus years of operation. The road hasn’t always been smooth, but the challenges we’ve faced – and overcome – make it easier for those who aspire to reduce their emissions through CCS,” Hatfield added.

According to Chevron and Hatfield, “CCS is a proven technology which experts agree is critical to achieving a lower carbon future while ensuring access to affordable and reliable energy for billions around the world who rely on it.”

Chevron is betting on CCS as one area in which it would invest in the coming decades. Unlike European supermajors, Chevron doesn’t have any plans to reduce its oil and gas business to invest in solar or wind power, chief financial officer Pierre Breber said at a Reuters conference last month.

At its annual investor meeting in March, Chevron said it plans to invest in low-carbon technologies such as hydrogen and carbon capture, utilization, and storage (CCUS).