Why Can't Coal Power Stations Quick Start with Natural Gas?

Coal fired power stations are used for the base electricity load in Australia, due to the  low cost of coal. For peak demand quicker starting natural gas power plants are used, which emit less carbon dioxide. I noticed that a new coal-fired power plant in West Virginia is using natural gas as part of its commissioning. This makes me wonder why a coal plant can't be started quickly using natural gas, then switch over to coal. That way they could be switched off when not needed, burning less coal.