 It produces about ten billion kilowatt hours of electricity from some five million tons of coal each year.All nine generating units are equipped with selective catalytic reduction (SCR) systems to reduce nitrogen oxide () emissions that contribute to the formation of ozone.In 1976, its original nine stacks were taken out of service (though left standing) and replaced by a pair of 1,000-foot (304.8 meter) tall chimneys, one for Units 1–5 and one for Units 6–9.