A closed dynamic input-output model is used to appraise the effects of specific pollution abatement and new energy technologies on the rate of economic growth and on the relative importance of sectors in the U.S. economy over the next 10 to 15 years. Three sets of structural changes are considered: (1) expected changes in technology for electric power generation, transmission, and distribution; (2) reliance on coal gasification for additional fossil fuel consumption; and (3) pollution abatement to meet stricter standards for six types of air, water, and solid waste pollution. All of these changes tend to reduce the long-run growth potential of the system. Taken separately, none of them has a striking effect on the capital and output proportions of the economy nor on its growth rate, but their combined effect could be substantial. However, the computations show that the effects of increased pollution abatement and energy costs could be offset by modest reductions in the growth of energy consumption or by increased rates of consumer savings.