Unit 2 at J-POWER's Isogo Thermal Power Station entered commercial service in July 2009. The 600-MW ultrasupercritical unit joins an earlier, similar plant built in 2002. Together, these two new plants replaced 1960s-vintage coal-fired plants and doubled power generation from the small project site. In addition, the new unit improves the plant's gross thermal efficiency to about 45% while reducing air emissions to those of a gas-fired combined-cycle plant.