Located at the tail-end of the national power transmission corridor of the northern region, Tamil Nadu is unable to avail itself of its due share from the Central generating stations in the north and even the declared surplus in the Delhi region.

The Centre has also not agreed to the reasonable request by Chief Minister Jayalalithaa for allotting to the State the entire power generated by the Centrally-funded power stations in Tamil Nadu, including that from the shortly to be commissioned Kudankulam, as an interim arrangement for one year until the State’s power projects are completed. Wind power would be available only from mid-May when strong pre-monsoon winds set in.

Anticipating the difficult power situation, Ms. Jayalalithaa unveiled in October 2012 an ambitious plan for 1000 MW of solar power. To be administered by the Tamil Nadu Energy Development Agency (TEDA) and TANGEDCO, the plan has met with lukewarm response from solar energy developers because of ambiguities in pricing and other uncertainties. Tenders for only 500 MW from eligible private developers are being processed. Ultimately, solar power from the developers is expected to flow into the State grid by the end of 2013. The situation is bleak for the coming summer.

Power shortage has affected all categories of consumers, big and small. It’s a fallacy that shutdowns reduce power consumption . The widely used standby power system — battery, inverter combination, for periods ranging from one to six hours for households, schools, hospitals, small business establishments and government offices — actually takes power in advance from the same supply mains and stores it in the battery. Power is saved only where this is inadequate and diesel engines are used. So the standby power cannot cope with shutdowns of 8-12 hours in force in many parts of the State.

Fortunately, the solar plan for Tamil Nadu includes decentralised captive power generation by rooftop systems for in situ consumption by individual households. This can either be independent of the grid (off-grid) or supplement the grid. A generation-based incentive of Rs. 2 a unit is planned for off-grid solar PV installations with a TANGEDCO approved meter.

As an illustrative example, a 3BHK residence needs about 300 units a month for efficient CFL lighting, fans, low wattage (<300 watts) kitchen appliances, a small TV& refrigerator and washing machine. Air-conditioners are excluded in this estimate. A properly installed 2.5-kWp solar PV system generates 10-15 kWh (units) during 8 a.m.- 4 p.m. on a sunny day (ie., 300-450 units a month). For high consumption electrical appliances, the household may have to depend on the grid supply but the monthly consumption will definitely move to the lower tariff slab and make a big difference to the net bill.

A million houses or apartments in Tamil Nadu installing similar rooftop systems will reduce the power demand from the grid by more than 10 million units (kWh) a day and enable shorter and less frequent shutdown periods. Similar rooftop systems of bigger capacities if installed in educational institutions, hospitals, and government offices for captive use could conserve hundreds of millions of units (kWh) and will result in considerable relief all round until the planned thermal stations, solar parks and solar power plants become operational.

Bank can chip in

A good 2.5-kWp system costs Rs 2.5-Rs. 3 lakh approximately. Already burdened with an ever-increasing cost of living, the middle class will find it difficult to pay this amount upfront. Public sector banks, which offer car and two-wheeler loans with attractive EMIs, can make a contribution to Tamil Nadu’s solar plan by offering loans for rooftop solar systems at low and affordable interest rates, say, 3 or 4 per cent. Foolproof modalities could be worked out for direct payment to the installing company and recovery of the loan from the user in affordable EMIs in five years.

Loans for buying cars and two-wheelers are meant for increased production of personal transport which, besides increasing traffic density, heavily pollutes the environment. On the other hand, assistance by banks to solar and wind power generation will contribute to green economy by reducing carbon emission, and resulting pollution and fossil fuel consumption.

For this plan to be succeed, rooftop PV systems must become mandatory for residential buildings, single houses or apartment buildings with an adequate terrace area exposed to the sun for at least six hours; and not affected by the shadow of adjacent buildings during 9 a.m.-4 p.m.; and this mandate is linked to the bank loan.

The State/Central governments must encourage banks to extend low interest loan facility for systems not exceeding 4 kWp. per household. It must also exempt PV solar developers, installers, and users from the VAT and service taxes.

Decentralised power generation from a large number of rooftop PV installations will result in a win-win scenario for citizens, the solar panel industry, and the government. And the banks, too, can claim carbon credit!

( D.V. Subramanian is a retired meteorologist. email: dvsmani1229@gmail.com )

A million houses or apartments in Tamil Nadu installing rooftop solar systems

will reduce the power demand from the grid by more than 10 million units a day.