Synchronous Condensers for India’s Evolving Grid: Leveraging India’s Retiring Generators for Reactive Power and Inertia Support

India has defined ambitious interim targets for 2030, including increasing non-fossil fuel–based installed capacity to 500 GW, meeting 50% of total energy requirements from renewable sources, reducing cumulative carbon emissions by one billion tonnes, and lowering the emissions intensity of GDP by 45% relative to 2005 levels.

Problem: Rapid growth of inverter-based renewables and retirement of synchronous generation are reducing system inertia, short-circuit strength, and dynamic reactive capability in the Indian grid. Although new synchronous condensers offer a technical solution, their deployment is constrained by rising material costs, long manufacturing lead times, evolving technology and skill requirements, and geopolitical-driven supply-chain risks, increasing procurement and execution uncertainty at a time of growing grid stability needs

Objective: The objective of this work is to demonstrate the technical feasibility, economic viability, and system-level benefits of converting retired synchronous generators into synchronous condensers, with the aim of restoring inertia, dynamic reactive power support, and short-circuit strength in renewable-rich power systems, while mitigating procurement uncertainties, skill-transition challenges, and supply-chain risks associated with new machine installations. This paper does not seek to compare synchronous condensers with alternative technologies that offer partial or overlapping grid-support functionalities.

Approach: The proposed approach utilizes publicly available government and industry data to identify representative classes of retired synchronous generators based on machine rating and type.A hypothetical mid-size turbo-generator case is then considered as a reference case to technical requirements for conversion to synchronous condenser operation, including retrofit, relocation, and auxiliary systems. Capital and operational aspects are assessed at an indicative level by comparing key cost drivers and operating characteristics against a large sized greenfield synchronous condenser installation.

Key Results: The study demonstrates that repurposed mid-size retired synchronous generators can provide meaningful contributions to system inertia, dynamic reactive power support, and short-circuit strength comparable to those of dedicated synchronous condenser installations.

The analysis shows that conversion and relocation of existing machines can achieve these benefits with lower indicative capital expenditure and shorter deployment timelines, while maintaining operational familiarity and established maintenance practices.

Value: The solution encourages the utilities to strengthen inertia and voltage control using available assets, minimizing capital exposure, execution uncertainty, and skill-transition challenges while maintaining long-term operability.