Unsustainably high internal demand for power in Kerala has already inflicted multiple power cuts on the state during evening peak hours. As if this was not enough, national factors caused further stretches of power cuts in Kerala during the last two days.

This week, high domestic demand in Kerala coincided with a huge mismatch in power demand and generation at the national level, posing a serious threat to the stability of the national grid. It was the safety of the national power system that necessitated these additional bouts of load shedding in the state. (The 'grid' is the high voltage backbone system of interconnected transmission lines, substations and generating plants.)

The crisis of the grid was particularly severe on September 15 and 16, and is expected to continue for the whole of September. On these two days, the grid frequency was outside the Indian Electricity Grid Code (IEGC) band. As per the IEGC, the operational frequency in the grid has to be maintained between 49.90 and 50.05 Hertz.

This is achieved primarily by distribution companies like KSEB accurately anticipating daily power demand and then planning the supply accordingly. On September 15 and 16, the grid frequency was outside the IEGC band for over nine hours, most of it during peak hours. This meant that the power utilities failed not just to foresee the increase in demand but also to ensure that supply kept pace; both demand- and supply-side management broke down.

A power-starved Kerala compounded the situation by drawing more power than what was originally scheduled from the national grid during these periods. On September 16, Kerala had overdrawn 4.67 million units (MU). On September 15, the overdrawal was 2.12 MU. There were other states also that, like Kerala, drained more power than they were supposed to from the grid.

The grid was, therefore, subjected to a twofold strain: unhealthy frequency and excessive power drain.

In times like these, to restore optimum frequency and protect the national power system from collapsing, the country's power mechanism automatically shuts down certain loads. "The grid was in a critical condition," a top KSEB official said. Since Kerala had overdrawn, feeders in various parts of Kerala were shut down these days for 10 minutes, and in certain areas for over an hour, to revive the grid. These blackouts were on top of KSEB's official power cuts.

At the national level, in response to the soaring temperatures and humidity, there was an additional demand of over 5000 MW in the last two days. Worsening the high demand was the fall in generation by an even greater quantity of 5500 MW. The drop in generation was witnessed mainly in the wind farms of Tamil Nadu and Karnataka, and this was caused by unusually low wind speed. Power experts say that the situation is unlikely to ease this fortnight.

Kerala's internal consumption, too, shows no signs of cooling down. Daily requirement on September 16 was 95.82 MU, the second highest this month after 96.39 MU on September 12. There was a shortage of over 900 MW on the day. At 10.23 pm alone on September 16, when the power requirement was the highest, the shortage was nearly 700 MW.

When the demand was over 95 MU, hydel, solar, wind and assured sources like central generating stations and long- and medium-term contracts together could provide only 81 million units on September 16. Normally, the difference is made up by short-term purchases. But on September 16, like in all other days this month, KSEB could manage just 3.5 MU from the short-term power markets.

A top KSEB source said that the demand on September 17, too, remained high. All attempts to purchase power during peak hours failed on Thursday, too.