nixos-config/modules/system/powersave.nix

{
  config,
  lib,
  ...
}: {
  options.myConfig.powersave.enable = lib.mkEnableOption "";

  config = lib.mkIf config.myConfig.powersave.enable {
    services.auto-cpufreq = {
      enable = true;
      settings = {
        charger = {
          governor = "powersave";
          turbo = "never";
          energy_performance_preference = "power";
        };
        battery = {
          governor = "powersave";
          turbo = "never";
          energy_performance_preference = "power";
        };
      };
    };
  };
}