The Hindu Business Line : TN, AP, Karnataka utilities overdrawing power

Chennai, Feb. 1 Electricity utilities in the Southern States, barring Kerala, have been drawing more than their entitlement of power from the Southern regional grid, paying heavy penalty in the process.

Data about the Southern regional load despatch centre on Power Grid Corporation of India's Web site shows that in 2006-07, Andhra Pradesh has notched up the highest overdrawal, followed by Tamil Nadu and Karnataka.

Any utility drawing power more than its entitlement is fined at rates fixed by the Central Electricity Regulatory Commission. The rate varies depending upon the frequency band.

After the implementation of the availability-based tariff system from 2003, all the utilities have to give their requirement in advance while the generating stations should specify the quantum of power that they will feed into the grid.

Any departure from the committed schedule - known as unscheduled interchange - is penalised.

For instance, if a utility draws more power than what it has specified that it would require, it would have to pay penalty to the other members of the regional grid.

Likewise, if a utility draws below its committed schedule, it will be rewarded.

The rate of penalty varies from Rs 2.04 a unit to Rs 5.70 a unit, depending on the frequency at which the overdrawal occurs.

The availability-based tariff system was introduced to ensure that States followed grid discipline and maintain the system frequency at acceptable levels.

It also changed the system of levying tariffs on generating stations. In ideal conditions, the system frequency has to be maintained between 49.5 Hz and 50.3 Hz, according to power experts.

In the South, Kerala State Electricity Board has earned more from the regional pool than it has paid into it, while Transmission Corporation of Andhra Pradesh (APTRANSCO), Karnataka Power Transmission Corporation Ltd and Tamil Nadu Electricity Board have paid more as penalty than they have earned from the grid.

Likewise, the inter-State generating stations - Ramagundam Super Thermal Power Station - Stages I, II and III, Neyveli Lignite Corporation and Talcher Super Thermal Power Plant, which supply electricity to the Southern regional grid - have all earned money from the regional pool for having pumped in more electricity than they had committed themselves to.

According to power experts, some States, at times, back down costly power, either from their own generating stations or private power projects, instead of preferring to overdraw from the regional grid, assuming that the total cost - electricity tariff and the unscheduled interchange penalty - is still lower than the cost of their own power.