$11.5 billion -- That's the amount of money that would be drained from the downstate economy if opponents, including Gov. Andrew M. Cuomo, were successful in closing the Indian Point nuclear power plant about 24 miles north of New York City, according to a report by the Business Council of Westchester. Because there are no plans yet to replace energy produced at the plant, the report postulates that a closure would boost electric rates in the metropolitan area 6.3 percent, or $374 million a year. Caution is required.