Since that time, generative capacities have grown exponentially, and technologies have evolved dramatically. Today's combined-cycle plants operate with greater efficiencies and lower emissions than any other type of fossil plant, and it's realistic to expect these numbers to continue to evolve and improve. Natural gas plants supply more than half the energy consumed in residential and commercial applications, and 41 percent of the energy used by U.S. industries, all while producing half the carbon dioxide, a third the nitrogen oxides, and one percent the sulfur oxides of the average coal-fired plant.