A top official of the regional grid operator that would be most affected by Energy Secretary Rick Perry’s proposal to subsidize ailing coal and nuclear plants said Thursday that the plan would impose a “sledgehammer” on competitive power markets and discourage investments in energy development.

Craig Glazer, vice president of federal government policy of PJM Interconnection, which operates the grid from Illinois to Virginia, said he recognizes the reliability and resilience challenges that the electric grid faces as coal and nuclear lose market share to natural gas and renewables.