The Karnataka Power Transmission Corporation Limited (KPTCL) has announced plans to gradually replace conventional mineral oil used in power transformers with environmentally friendly ester oil, marking a significant step toward building a greener and safer electricity transmission network. The initiative is part of the utility's broader strategy to modernise grid infrastructure while reducing environmental risks associated with transformer operations.

The transformer oil is highly essential in terms of cooling and insulation of electrical devices. The mineral oil that is made up of petroleum products has been used in the past as the main insulating agent in transformers. But due to safety, environmental issues, and dependency on crude oil products, there has been a move towards finding alternative technologies. And this is where the ester oil comes into focus because it is eco-friendly and non-flammable.

According to reports, KPTCL has already embarked on the change process through the conversion of several high-capacity transformers to natural ester oils. Instead of changing the entire transformer units, the utility identifies older units and then upgrades them through retrofilling, whereby mineral oil is changed to ester oil for better efficiency and increased longevity.

One of the major advantages of ester oil is its superior fire safety. Synthetic ester fluids have a much higher fire point than conventional mineral oil, making them particularly suitable for substations located near urban centres, industrial facilities and environmentally sensitive areas. The technology also reduces the risk of soil and groundwater contamination in the event of leaks because ester oil is biodegradable.

This is happening amid the growing inclination of the Indian power industry towards adopting sustainable transmission solutions. In a recent development this year, POWERGRID installed India's first 315 MVA synthetic ester oil-filled transformer at the Bhiwadi substation, showing how esters have been accepted for insulation purposes in high voltage transformers.

The modification has also been done in line with recently released guidelines from the Central Electricity Authority (CEA) which recommended that ester oil be used in at least 10% of new transformers and reactors with 33kV and above voltages. Some of the advantages listed in the guidelines include fire safety and sustainability among others.

As renewable energy capacity continues to grow and electricity demand rises, utilities are under increasing pressure to improve grid reliability while reducing their environmental footprint. The adoption of ester oil technology is expected to support both objectives by extending transformer life, improving safety standards and contributing to cleaner power infrastructure.