What is your estimate of lifespan of a 1500 mw powerplant? Bear in mind boilers can be re-tubed, turbines rebuilt and auxillary equipment replaced. Longevity estimates are sometimes made for bond issues, regulators or other single issue bodies. These estimates may have no real basis.
It uses 13-14 thousand tons/day.
Don't know. But the famous coal-fired Battersea Power Station's boiler 1 lasted 36 years, boiler 2 less than 30. In the end, it'll all boil down to the numbers, but with compliance costing more than the today's-value cost of the original plant with no increase in output, efficiency, or longevity of the actual power systems it doesn't look good to me.