Welcome domestic solar power

Jagvir Goyal

When the Chandigarh Administration made it mandatory to install solar panels on rooftops of larger houses (1 kanal and above), several residents had some reservations regarding compliance. The general impression was that this was an “avoidable” expense which the authorities were imposing on them. But it is, in fact a laudable effort. A few years ago the directions regarding the installation of rainwater-harvesting system in the houses had also evoked a similar response but now it is a well-accepted norm. Installation of solar panels on rooftops of houses is a step towards power conservation by harnessing plentiful solar energy available in the region. Let’s have a look on some aspects of a domestic solar power unit:

Plot size

Solar panels and power production unit can be installed on the rooftops of houses on any size of plots. Ten marla or 250 square yard plot houses can conveniently accommodate solar panels for the production of 3 KW of power. While 350 square yard houses can have 5 KW power solar plants, 1 kanal houses can have 8 KW power plants. These figures may vary depending upon the availability of rooftop area of the houses.

Area required

About 110 square feet of rooftop area is required for production of 1000 watts or 1 KW of power. Therefore, a 10 KW connection will demand rooftop area of 1,100 square feet and a 3KW connection will need 330 square feet area and so on.

Cost of installation

The cost of installation of solar power plant on the rooftop is about Rs67,000 per KW. The cost per KW decreases with the increase in KW quantity. A 10 KW plant will cost about Rs6 lakh instead of Rs6.7 lakh. A 5 KW plant costs around Rs3.20 lakh. More the KWs to be produced, the lesser is the cost per KW.

Subsidy

In order to attract more people towards utilisation of solar power, Government of India provides 30 per cent subsidy to the people. This subsidy may continue for the few initial years only. The subsidy amount is reimbursed directly into the account of the resident using solar power unit. After accounting for the subsidy, the net cost per KW comes down to about Rs50,000 per KW.

Maintenance concerns

There are a few maintenance concerns involved in rooftop solar power generation system and these should be left to the installation agency. One shouldn’t try to clean the solar panels on one’s own or walk on them. So maintenance of solar power unit is not a major issue for the house owners.

Saving in electricity bills

The generation of solar power depends on the weather scenario of the area in which the solar plant has been installed. In Punjab, Haryana and Chandigarh, a solar power plant conveniently generates about 1,300 units per KW installation per year. At an average cost of Rs8 per unit, it brings a saving of Rs10,000 per KW per year. The equipment cost, therefore, can be recovered in about five to six years.

Plan it initially

It will be an ideal situation if one plans to install the rooftop solar panel system at the time of house construction itself. In India, the rooftops having AC outdoor units, water tanks, vents fitted on them make it difficult to install the solar panel unit, facing a favourable direction for maximum power generation and also avoiding shadows. South is the most favourable direction to face solar panels.

Metering

As the house owners can’t totally depend on solar power only, an electricity connection is also required for the house. With the advent of solar power, metering system has also come of age. Bidirectional and net meters are now available and one can check import and export of power as well as net metering also. Surplus power gets supplied to the electricity department grid and electricity bill is issued to the consumer after adjustment of import and export of power.

Whom to contact

For the installation of solar power unit, one should contact the Akshya Urja shops or other such shops that are empanelled with bodies like PEDA and MNRE to avail the subsidy without any problem and to lodge complaint in case of any problem. These shops know that your complaints to MNRE, PEDA or Energy Development Agencies may create trouble for them.

Equipment

The rooftop solar power generation unit uses photovoltaic cells and includes solar panels mounted over a supporting structure, HPV modules, some cables, solar inverters and other accessories. The capacity and size of the solar panels determine their efficiency in power production. The job is assigned on supply, installation and commissioning basis to those in solar power business. One should avoid choosing Chinese solar panels that are bit cheaper than the Indian ones. The supporting structure is either light weight or medium or heavy. In residential areas, one may safely choose medium weight supporting structure.

— The writer is a former HoD and engineer-in-chief, Civil Engineering Department in a Punjab PSU