Buildings are experimenting with alternative energy with small wind turbines on rooftops

In the last few weeks, the city has had a respite from its daily burden of two-hour power cuts — wind energy has helped reduce load shedding to one hour a day. Thanks to the huge wind turbines that dot the State's southern coast, much-needed power is supplied to grids.

Of late, some buildings in the city have begun to take their own measures to go green. Small wind turbines have cropped up on several rooftops. These green buildings use natural lighting, conserve every drop of rainwater and use solar energy. Now, they are also going in for wind turbines – known as hybrid systems, where the charge controller, battery and inverter are common for both the solar as well as the wind system.

A happy rooftop power producer is Navadisha Montessori School in Velachery, which has been using such a system for six months now, to power the EPBAX, four fans and a computer. “The trustees decided to go in for green energy on a small level at least. Ours is also a rainwater harvesting structure,” said a source at the school.

“Ideally the consumer has to spell out his demands. The contribution of solar and wind energy is location-specific. For instance in Ladakh, 90 per cent of power comes from wind energy and 10 per cent from solar power. Equipment for one kilowatt of installed power of a hybrid system would cost around Rs.2.50 lakh, which is not inclusive of the government subsidy,” said C. Raghuraman, founder of E-Hands Energy, a micro wind energy solution provider.

“Though many people don't seem to even go in for the government subsidy as they want to go green, if somebody is looking for a subsidy, they need to look for companies that are empanelled by the Centre for Wind Energy Technology (C-WET) under the Ministry of New and Renewable Energy or other competent laboratories,” said S. Gomathinayagam, Executive Director, C-WET.

K.R. Jagadeesh Babu, general manager of Solkar Solar Industry however, said that wind turbines were not yet suitable for domestic installation, as their use depended on wind velocity. “They are not as reliable as solar energy, as you cannot predict when the wind will stop blowing,” he said. Nevertheless, there are wind turbines that run for 250 – 300 days a year and the smallest ones can have a capacity of 0.3KW and cost around Rs.60,000.

Solar products that had a lead over wind ones, are also being invented in newer forms now. Manufacturers point out that solar inverters and solar power plants are highly sought-after products. “People who were so far mulling over the use of solar products are now purchasing them. They are affordable now compared to earlier, as prices have come down. Solar inverters are priced between Rs.28,000 and Rs.40,000,” he said.

However, the day is not far off when domestic consumers can pitch in with supply to the city's power grid. Residents could provide the surplus electricity generated from their solar plants to the government, for which incentives could be provided.

P. Ashok Kumar, president of the Tamil Nadu Energy Developers Association and a member of the governing body of Tamil Nadu Energy Development Agency, said that the State government's Green Power Policy is in its final stages.

The policy will make the State's stand on net metering or reverse metering. There is already talk going around to the effect that the government is considering implementing net metering.

The Tamil Nadu Energy Developers Association has recommended that the setting up of solar power plants in commercial and large residential buildings be made mandatory. This concept has been successfully implemented in Europe, he said.

T. Vijayakumar, GM, special projects, of wind power technology major, Gamesa, said, “Other States like Karnataka, Maharashtra and Gujarat have given a big push to renewable sources of energy. In Mumbai, common areas in large apartment complexes are lit by hybrid power plants. This is because solar power prices are on par with those supplied through the grid. In Tamil Nadu, if you compare prices, solar power is higher by Rs. 2 to Rs.3.”