India witnesses one of the fastest phases of economic growth, resulting in the fifth largest economy in the world. Further, the country surpassed China in terms of its population in 2023 and has the largest population in the world. Subsequent to policies resulting in a growth in manufacturing sector coupled with rapid urbanisation, large spending on infrastructure and housing, there has been a massive demand for electricity in India. Power generation companies play an important role in India’s economy. However, there are lots of concerns in the power companies in India, including transmission and distribution losses, emissions of hazardous gas, and reliance on exported coal for production, which in turn makes the production costlier, resulting in weaker utilisation of resources. In this context, it is crucial to address how effectively the power companies in India utilise their resources. The study analyses the technical and scale efficiency of select private power companies in India during 2022–2023 financial year using Data Envelopment Analysis (DEA). The study has used an input-oriented model with multiple inputs, including number of employees, and capital expenditure, and outputs such as total power generated and total revenue with alternate models. The study also adds to the literature by also including undesirable output like sulphur dioxide emissions. The study finds that private companies are only 64–70% technically efficient during the period and the Reliance Power is the only company which is technically efficient across the alternate models. The scale efficiency estimates show that most of the companies are increasing returns to scale which calls for further possibility of expansion of production. The study further calls for research in the direction of more measures by considering the measures taken by the power plants to check emissions as input variables and to correlate with undesirable output as well as addressing the transmission and distribution of energy loss.