The expansion of the Trombay Thermal Generating Station became imperative to meet the escalating power demands in Mumbai. The Tata Electric Companies sought governmental approval for the installation of a fifth unit at Trombay, proposing a substantial 500 MW capacity - the largest in the country at the time. To finance this ambitious project, assistance from the World Bank was sought.

Following prolonged discussions and a five-year period of inactivity awaiting Central Government clearance, the Government of India granted approval in 1977. Tata Electric received the green signal to proceed with the project, opting to entrust TCE with the detailed engineering and procurement services, while Ebasco Services Inc. was retained as a Review Consultant to scrutinise critical aspects of TCE’s design.

The Trombay Unit 5 Project reached completion in 1984, and even during its implementation, Tata Electric was already contemplating further expansion. A proposal for another 500 MW unit faced unexpected resistance, not from authorities who readily approved it given the pressing power situation, but from environmentalists. Eventually cleared on the condition of utilising only clean fuels to prevent environmental pollution, this project, known as Trombay 6, was also engineered by TCE in Bangalore.

Due to opposition from environmentalists and space restrictions preventing additional units at Trombay, Tata Electric proposed replacing Units 1, 2 & 3. Each over 30 years old and having served their useful life with a 205 MW Combined Cycle Power Plant. This forward-looking project received approval and World Bank aid, similar to the Trombay Units 5 & 6 Projects. TCE was again retained as a consultant, overseeing the project’s completion in 1996.

The project seamlessly integrated a myriad of advanced design elements, exemplifying a commitment to innovation. Noteworthy for being India’s inaugural 500 MW power plant exclusively designed by TCE, it proudly featured a 275-meter chimney, the tallest in Asia. This exceptional design earned TCE several prestigious awards. The project culminated in a successful completion in 1991.