FirstEnergy Corp.’s subsidiaries reached a settlement that would allow the companies to flow back $900 million in savings from the federal tax cut law that lowered the corporate income tax rate to 21 percent from 35 percent. The company said that the tax savings would be credited through a new mechanism reconciled annually, and that treatment of savings not reflected in riders will be effective Jan. 1, 2018 continuing until rate changes are implemented in the next base rate case. The settlement filed with the Ohio Public Utilities Commission on Nov. 9 would allow the company to invest over $500 million to modernize the grid including the installation of 700,000 smart meters and establishing time-varying rates. The company said that the grid modernization efforts are consistent with Ohio’s PowerForward initiative, which seeks to foster innovation that allows for an enhanced experience for customers. The utilities are Ohio Edison Company, The Cleveland Electric Illuminating Company, and The Toledo Edison Company.