The United States Postal Service (USPS) on Tuesday said it would buy only electric delivery vehicles from 2026 on, an about-face from the agency's original plan to continue with internal-combustion powertrains for most of its next-generation fleet.

The USPS plans to acquire 106,000 vehicles between now and 2028, of which at least 66,000 vehicles will be battery-electric, the agency said in a press release. The plan, which aims to replace an aging deliver fleet that currently numbers 220,000 vehicles, will cost $9.6 billion, with $3 billion coming from the Inflation Reduction Act (IRA).

Under the current plan, at least 45,000 of the USPS' Next Generation Delivery Vehicle (NGDV) mail trucks, designed specifically for the USPS and built by defense contractor Oshkosh, will be battery-electric, representing 75% of the planned 60,000-vehicle fleet. The USPS also plans to acquire 21,000 EVs based on off-the-shelf designs.

USPS Motiv Power e450 delivery truck for Fresno, California

USPS Motiv Power e450 delivery truck for Fresno, California

"The Postal Service also anticipates including internal combustion vehicles necessary to meet immediate vehicle replacement needs," the release noted. Feasibility of a 100% electric USPS fleet "will continue to be explored," according to the agency.

The first NGDV mail trucks are scheduled to enter service in late 2023 as replacement for the aptly-named Long Life Vehicle (LLV) trucks that have plied mail routes for decades. The USPS initially had a much more conservative electrification target—which proved controversial.

The USPS in February 2021 revealed plans for the next-generation trucks, with only 10% electric—after President Biden had made an executive order emphasizing EVs in federal vehicle purchases. That led to lawsuits from states and environmental groups.

USPS Next Generation Delivery Vehicle - Oshkosh Defense

USPS Next Generation Delivery Vehicle - Oshkosh Defense

This past summer, the USPS gave into pressure, boosting its plan for EVs to half of the future fleet. A look into some the original USPS analysis behind the electric mail trucks was released around the same time, and found it to be "significantly flawed"—especially in its life-cycle assessment, which made a strange assumption that the grid wouldn't get any cleaner than it was at present.

As we reported earlier this month, there aren't a lot of EVs currently available to federal agencies. The Ford F-150 Lightning was the first electric pickup officially available, but Ford's closing of orders bumped it off the list for the time being. The NGDV mail trucks are being built for the USPS specifically to a bespoke design, though, so the agency has had an opportunity to order up the ratio of each vehicle type it needs.