The nation’s largest public utility plans to switch out 1,200 of its vehicles for electric ones by 2030. Tennessee Valley Authority officials announced the plan during a board meeting Wednesday. They say the changeout will include reducing the fleet’s 600 light-duty vehicles to 400 electric versions and initially changing out 800 medium-duty vehicles, representing half of the federal utility’s pickup trucks. The plan coincides with the rollout of efforts to install fast-charging stations every 50 miles along major thoroughfares in Tennessee, extend charger installation across the region and coordinate with utilities on the effort outside the utility’s seven-state region.