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Wind proves to be unsteady source

CHENNAI: Just as agriculture in the country is a gamble on the monsoon, the power situation in Chennai has become a gamble on wind. The city, which is facing rolling power cuts and other unscheduled outages, may be suffering the consequences of an unbalanced development of wind power in the state. With conventional power generation capacity stagnant for the last 10 years in Tamil Nadu, wind has become the marginal, peaking power expected to meet the city’s additional power needs exactly the wrong application for wind power, say experts.

Wind power accounts for a little less than 30% of the state’s overall capacity. Much of it has been installed in the last 10 years when not many major conventional plants have come online. “Tamil Nadu has put too many of its eggs in the wind basket,” a central agency official says.

Wind, being a widely varying natural phenomenon, is an unsteady source of power and wind power varies on a day-to-day and monthly basis.

Tamil Nadu, known as the most suitable state for development of wind power, boasts of strong winds but only between May and October. In November, wind generation goes down dramatically. Even within a month during the peak season, wind generation can fluctuate sometimes up to 100%.

Experts say integrating fluctuating wind power into the grid is a challenge all over the world: One that has been tackled in various ways. “You have to plan for renewables,” says Rangan Banerjee, professor in the department of energy science and engineering, IIT Bombay.

Typically, wind is introduced in areas with surplus power, so that if wind power sags, other forms of power generation are ready to ramp up on demand. Wind forecasting needs to be improved in Tamil Nadu, says Banerjee, so that other plants can be scheduled to provide steady power to consumers.

Also, while introducing large amounts of wind power into the grid, other plants need to be redesigned so that they can respond quickly to fluctuations in grid power from wind. Hydro power can be such a source. Maharashtra, for instance, uses pumped energy storage from which power can be drawn on demand when wind power dips, says Banerjee.

Gas-fired plants are another excellent source that are flexible enough to handle wind power. These are the plants of choice in all nations that are increasing wind capacity, experts say.

Grid integration of wind often involves power generating companies banding together in a network, says an official in a central agency. “This ensures that no generating company or region is penalized for choosing an environmentally friendly source of power,” says the official.

“But for that to happen, power generation, distribution and transmission should be done on a commercial basis.” Since these companies are owned by state governments, there is little likelihood of that happening, he adds.

Meanwhile, Tamil Nadu plans to increase its wind capacity there’s potential for another 5,000 MW of wind power in the state. The official hopes that by that time the state will either build enough conventional capacity to act as buffer or strike up commercial agreements with other states to handle wind power.