 The Act required that, prior to constructing or modifying an electric generating plant, the Commission was to certify the need for the plant and the suitability of the site of the plant.In 1976, the California legislature amended the Warren–Alquist Act to require the Commission, prior to any new nuclear generating plants being built, to certify that there is sufficient capacity to store spent fuel rods, and to establish a moratorium on the certification of any new nuclear generating plants until the federal government has approved and established a means for the disposal of high level nuclear waste.A legal challenge to this amendment by two electric utilities resulted in the United States Supreme Court case "Pacific Gas & Electric Co. v. State Energy Resources Conservation and Development Commission", which upheld the amended Act.