Florida Power & Light is scheduled to implode the 495 -foot (150-meter) chimney stack of its last coal-fired generating plant on Wednesday, a milestone in its full transition to cleaner energy sources. A demolition company will use 171 pounds (78 kilograms) of explosives to implode the stack and an adjoining conveyor building in Indiantown, 30 miles (about 50 kilometers) north of West Palm Beach. The plant was built in 1995 and FPL purchased it in in 2016. It shut the plant down more than two years ago. FPL will tear down the rest of the plant later this year. The company hasn’t said what it will do with the site, but it has been investing heavily in natural gas and solar-powered plants. FPL is the state’s largest electricity producer, serving most of the Atlantic Coast and the Gulf Coast south of Tampa Bay.