In 2021, Australian gas producer Santos unveiled ambitious plans to turn the near depleted Bayu-Undan gas field in the Timor Sea into a carbon capture and storage (CCS) facility. In the three years since, Santos has yet to disclose the costs or provide technical details on the world’s largest CCS venture proposal. The project also presents many legal and regulatory risks.

The Bayu-Undan announcement followed Santos reaching final investment decision on its Barossa gas project, also located in the Timor Sea. The company plans to start producing gas from Barossa in 2025, and it claims the project will have net zero emissions from day one. This is a bold claim given Barossa will be the most carbon-intensive gas field to supply feedstock to an Australian LNG project, with carbon dioxide (CO2) content of 18%. 

Santos’s net zero claim on Barossa is contingent on burying some of the CO2 it produces at Bayu-Undan. Santos plans to develop the world’s largest CCS facility, and one of the most complex, with CO2 moving through almost 800km of pipelines and across maritime boundaries.

To date, Santos has not published an offshore project proposal or environmental impact statement on Bayu-Undan CCS, as would be expected for a venture of this scale. Instead, Santos says only that it intends to sanction Bayu-Undan CCS in 2025 and start injecting CO2 into it from 2028, buying carbon credits in the interim. Santos still requires regulatory approval for some of the CCS infrastructure, and it has no permits in place to allow it to send CO2 to Timor-Leste.