With 12 percent of U.S. electricity now being supplied by nuclear power, Commonwealth Edison has found nuclear plants to be good investments relative to other base load energy sources. The country's largest user of nuclear power, Commonwealth Edison, estimates that its commitment to nuclear saved its customers about 10 percent on their electric bills in 1977, compared to the cost with the next best alternative, coal. This advantage is seen as continuing, contrary to criticisms of the economics and reliability of nuclear power and claims that it has hidden subsidies. It is concluded that there is a need for both nuclear and coal and that government policy precluding or restricting either would be unwise.