Lower city embedded generation a cause for Mumbai power cuts: Tata Power

Lower city embedded generation a cause for Mumbai power cuts: Tata Power

Mumbai’s decreasing dependence on City Embedded Generation (CEG) is one of the reasons for it being more prone to power cuts, senior officials of Tata Power told Moneycontrol on June 5 – World Environment Day.

Frequent power cuts, even in high-end locales like Bandra, have been occurring in the past fortnight.

While discoms, or distribution companies, primarily attribute the power cuts to immediate “external reasons”, such as overload and cable damage, Tata Power officials said a long-term reason could also be the weakening of the city’s islanding system due to lower dependence on CEG.

What is CEG?

CEG refers to electricity generation or storage plants connected to a distribution network rather than to the transmission network, according to the UK’s ESO (Electricity System Operator). Most regions of Mumbai have an embedded generation installation, thus facilitating an ‘islanding system’.

Islanding refers to a condition in which a consumer continues to get power even when there is disturbance in the external grid. This was achieved by isolating the distribution network from the adjoining external grid. After isolation, the power demand is managed through generation sources embedded within the island, which was intentionally planned to keep pace with demand.

Tata Power officials, during a media tour of its Trombay Thermal Power Plant on June 5, said the “CEG is continuously reducing with increasing power demand, making the islanding system more vulnerable to failure during system disturbance”.

Data provided by the power company showed that since 2011, the embedded generation of Mumbai has been on a steady decline, whereas power sourced from outside has been increasing.

This means that Mumbai is sourcing more electricity from external stations, such as national grids and renewables, because of which the city’s islanding system is frequently disrupted, leading to power cuts.

On June 1, the Trombay plant reached a peak demand of 3,951 megawatts (MW). But the city’s pre-established CEG system now only provides approximately 1,500 MW of the peak demand of about 4,000 MW.

Push for renewables

As a mitigating measure, Tata Power is now adding renewables to its city-based generation portfolio as thermal power plants are polluting, way more expensive, and take much longer to be built.

P Devanand, Chief of the Power System Control Centre at Tata Power, said that though a challenging task, Tata Power is working on floating solar cells, and looking at batteries for energy storage and transfer, in terms of bringing renewable energy under CEG.

Running the decommissioned 500 MW Unit 6 of the Trombay plant, with naphtha and green hydrogen, is also being looked at as a possibility. They have also tried utilising biomass pellets to generate power, citing it an expensive method.

Speaking to journalists on World Environment Day, panellists from Tata Power also highlighted the various environmental activities taken up by the Trombay plant, such as production of tetrapods with bottom-ash, instead of sand.

“Currently, the plant is sourcing ‘Enviro-coal’, a low-ash, low-sulphur coal from Indonesia, and is looking at greener techniques for power generation in the years to come. The employees also undertake tree plantation drives as a part of the 33 percent green cover legislation for thermal power plants,” Shirish Kamat, Chief of the Trombay Tata Power plant, said.