After Prime Minister Narendra Modi's call to switch off lights for 9 minutes on April 5, the power ministry has reiterated that Indian grids are robust and and stable, and the Power System Operation Corporation (POSOCO) has issued advisory to be followed by state and regional despatch load centres to maintain grid balance.

The power ministry has clarified that lights in hospitals and all other essential services like public utilities, municipal services, offices, police stations, manufacturing facilities, etc will remain on and local bodies have been advised to keep the street lights on for public safety.

"Some apprehensions have been expressed that this may cause instability in the grid and fluctuation in voltage which may harm the electrical appliances. These apprehensions are misplaced. The Indian electricity grid is robust and stable and adequate arrangements and protocols are in place to handle the variation in demand" said SN Sahai, Power Secretary. Power System Operation Corporation (POSOCO) has issued advisory to all regional and state load despatch centers. The advisory has been issued to ensure the reliable and secure operation of systems to ensure there is no imbalance on the power grids.

POSOCO estimated electricity demand reduction on the basis of the March 29 (day of Janata Curfew) demand pattern. It has observed that all India demand was at around 1,01,207 MW at 18:07 hours and it subsequently increased up to 1,12,551 MW at 21:00 hours during the peak period.

Source: POSOCO

Taking an account of the load behaviour it is anticipated that total demand reduction for the April 5 event is likely to be in the range of 12,000 to 13,000 MW. "Unlike normal operation, this reduction in load of the order of 12-13 GW would happen in 2-4 minutes and recover nine minutes later within 2-4 minutes. This sharp reduction in load and recovery, which is unprecedented, will need to be handled through hydro and gas resources identified" as per advisory.

Source: POSOCO

The advisory has also guided all grid operators to maintain frequency at the lower side of 49.90 hertz starting 8:30 pm. for the power generators, it has asked hydro and gas-based power plants to start ramping up starting 8:57 pm and thermal power generation plants starting at 9:05 pm to meet the sudden demand of electricity once India switches on its lights.

Some states like Tamil Nadu, Uttar Pradesh and Maharashtra have raised the issue of grid balance on account of switch off and switch off event on April 5, many states including them are keeping its technical team on toe in case of any eventualities.