Review policy, promote rooftop solar power system

The article written by Saptak Ghosh (December 23, 2015) has brought out the issues relating to the slow progress in the installation of roof top solar photoelectric units (RTPV). It is relevant to point out here that preference needs to be given to RTPV over conventional solar photovoltaic units (SPV) of MW scale such as the one of 5MW capacity installed at Sivanasamudram in Karnataka for several reasons.

Not many are aware that SPV systems are land guzzlers and 1 MW of plant requires as much as five acres of land. Thus, 25 acres of precious cultivable land has been gobbled up by the 5MW plant at Sivanasamudram. The justification normally given for the installation of MW size SPV units is that land not cultivable is being planned for installation of SPV units.

It is to be pointed out that except in Rajasthan where desert exists, even arid land would be required for purposes other than agriculture. Preference therefore needs to be given to roof top units even if the cost per KW of installed capacity is slightly higher. Another advantage of RTPV is that electricity produced is consumed at the point of generation resulting in lower distribution loss which is another form of energy conservation.

Yet another fact which is not known to many is that in the case of large solar photovoltaic units, the tariff worked out by the Karnataka Electricity Regulatory Commission ensures the firm gets a return of 16 per cent on its equity after meeting all other expenses including operation and maintenance, depreciation, interest on loans.

In the case of people who install roof top units, they would be happy even if they get a return of 10 to 12 per cent on their investment which results in lower cost per unit to the ESCOMs which are required to purchase a certain quantum of electricity produced from renewable sources of energy under Renewable Energy Obligation (RPO).

Taking the above factors into consideration, production of electricity from roof top units should be promoted even though the cost of energy will be marginally more expensive than that from larger units.

The main cause for RTPVs not being installed in large numbers can be attributed to the imposition of ‘net energy concept’ which is ill-conceived for more than one reason. Firstly, it tantamounts to discrimination as compared with the supply from a larger unit. Whereas a firm which installs a large unit gets paid for every unit it supplies to the grid, the electricity supplied by ESCOM and consumed by the owner of the roof top unit house is deducted from the quantity of electricity he produces from the SPV unit installed on the roof of his home. The impact of this discrimination becomes clearer by an example.

Suppose a house owner installs a 2KW solar unit on his roof. Normally it would produce 3,000 units per year or 250 units on the average per month. Assuming that he is consuming 250 units per month, the electricity produced by him in his RTPV unit gets fully adjusted towards the electricity he consumes and he does not get paid any amount for the electricity he produces other than the fact that he is exempted from paying the electricity bill.

In other words, this is equivalent to getting paid for the electricity he produces in his SPV unit at about Rs 5-6 per unit by the ESCOM for the energy he produces instead of Rs 9.56 per unit. This is totally unjustified and discriminatory.

In contrast, the owner of a larger unit gets paid for every unit he supplies to the grid though at a slightly lower rate of Rs 8.40 per unit. This is clearly a case of discrimination. The net benefit that a person gets by installing a RTPV varies from consumer to consumer depending on the quantity of electricity he produces and purchases from the ESCOM.

Cost of meter

Once a consumer is assured that he would get paid at a rate approved by the Commission for every unit he produces, it is certain that a number of house owners would install RTPVS and the targets set by the government in respect of capacity of solar photovoltaic units would be achieved and may be exceeded in a short time.

There is yet another point which deserves attention by the authorities. The ESCOMS intend replacing the existing meters of house owners by bi-directional meters to assess the net energy supplied by the consumer. A far simpler system is to install a meter after the terminals of RTPV and the connection from the SPV terminals given to the grid on the upstream side of the existing meter.

The consumer could be made to bear the cost of the meter which can be calibrated by the ESCOM. The bill to the consumer will be the difference between the amount to be paid by the consumer for electricity he consumes and the amount payable by ESCOM to the consumer for the electricity supplied by him to the ESCOM.

It is also desirable that the capacity of RTPV is restricted to a value such that the amount payable by ESCOM for the electricity supplied by the consumer is less than the amount payable by the consumer. Such a condition will alleviate the necessity of amount payable by the ESCOM which could result in complaints and even disputes.

It should be appreciated that the licensee has the obligation to supply electricity to any consumer at the rates approved by the Commission from time to time. This obligation should not be linked with the electricity produced by a person on the roof of his building.    

(The writer was Chairman, Karnataka Electricity Board and Director, Karnataka Power Corporation)