The 726.6 MW gas-based unit, being built by its subsidiary ONGC Tripura Power Corp Ltd, "is a fuel- substitution project, which would mitigate over 1.6 million tons of carbon-dioxide emissions per year for the next 10 years," it said in a statement here.
"Fetching 1.6 million carbon credits per year, this is one of the biggest CDM projects in the world," it said.
With this registration, ONGC now has 10 registered CDM projects.
The project is being developed by ONGC as a joint venture with the Tripura government.
Speaking after the registration, ONGC Chairman and Managing Director Sudhir Vasudeva said, "Our sustainable development record is commendable. Our commitment to sustainable development is organically integrated to our Exploration and Development of energy assets".