Onam season could have induced a spike in the sugar levels of Malayalis, but it has caused a pronounced drop in another kind of consumption: electricity.

From a high of 92.39 million units on August 20, daily power consumption in Kerala slid to 87.93 MU on August 24 (Pooradam day, Monday), then dropped more steeply to 81 MU on August 25 (Uthradom) and from there went on a near free fall to 72.78 MU on August 26 (Thiruvonam).

Though offices and business establishments reopened, consumption still remained low on Avittom (August 27), Chathayam (August 28) and Pooruruttathi (August 29) days also; at 78 MU, 82 MU and 84 MU respectively.

So while Malayalis went on an Onam spending spree, Kerala State Electricity Board Limited could, for a brief period, suspend its crazy spending habits. While it had to purchase 11-12 million units at exorbitant rates from the Day Ahead and Real Time markets during most of August, its outside purchases fell by more than half to below 4 million units during the Onam season.

"This is a huge but temporary relief for the KSEB as the cost of power during peak hours is as high as Rs 10 a unit," a senior KSEB official said. Fact is, Kerala has been suffering a power deficit of around 200 MW throughout the year.

The KSEB official cited four factors that had pushed up both daily consumption and KSEB's purchase costs in recent times, and eventually necessitated power curbs. One, weak monsoon. Two, critically low reservoir levels. Three, persistent base Load Generation Balance (LGB) deficit (difference between power generation capacity and demand). And four, non-availability of adequate power during peak hours.

The Onam season has now offered a temporary respite. "Of course, consumption falls during holidays because offices and some businesses, too, would be shut. But in the case of Onam, the fall in daily consumption is more noticeable because the average household consumption also weakens. This is particularly so during Onam because families get together in one location, at their ancestral home for instance, for up to even three days to celebrate. This will leave multiple houses unoccupied, with near-zero demand for power from them," the KSEB official said.

However, there is a major concern. KSEB has been overworking its hydel reservoirs. Over 25 MU are being generated on a daily basis from its major units like Idukki (780 MW), Lower Periyar (180 MW)and Sabarigiri (340 MW).

The problem is, Kerala's hydel stations do not have enough water storage to support such high generation. It is usual to make hydel stations slog during the post-monsoon period. Last time, during the post-monsoon period, Kerala's reservoirs were 80 per cent full. But this time, thanks to the erratic southwest monsoon, it is only 64 per cent. Caution, and not gambling instinct, is therefore advised while operating hydel stations.

Take, for instance, Idukki. Last year same time, it had water to generate 1633 MU of power. It could be safely over-exploited. This year, its storage can generate only 1365 MU.

Nonetheless, there is a reason why KSEB is over-reliant on its hydel stations. They have terrific reflexes, unlike a coal or nuclear-based power plant. "Turbine acceleration can be achieved in no time by simply releasing more water through the penstock pipes," a KSEB chief engineer said. Other kinds of power plants do not have such quick reaction time in times of distress.

However, there could be trouble if more water than is sustainable is drained out of KSEB's reservoirs at this stage and the northeast monsoon, which ordinarily begins in October, turns out to be as unreliable as the southwest monsoon.