The decision dashes the hopes of the Biden administration, which had lobbied the independent agency to switch to a predominantly electric vehicle fleet. It also ends any chance, at least in the near term, for any EV manufacturer to capture some of the contract estimated to be valued at $6 billion. The Postal Service finalized its decision, which it outlines in a 384-page document, after reviewing comments from the Environmental Protection Agency and evaluating the potential environmental impacts of its next-generation delivery vehicle (NGDV) program.

Under the approved program, USPS will buy between 50,000 to 165,000 mail trucks from the Wisconsin-based Oshkosh Corp. About 10% of those would have to be electric. The vast majority, and up to 90%, of the fleet would be gas-powered vehicles.

“As we have reiterated throughout this process, our commitment to an electric fleet remains ambitious given the pressing vehicle and safety needs of our aging fleet as well as our fragile financial condition. As our financial position improves with the ongoing implementation of our 10-year plan, Delivering for America, we will continue to pursue the acquisition of additional BEV as additional funding — from either internal or congressional sources — becomes available,” Postmaster General and USPS Chief Executive Officer Louis DeJoy said in a statement. “But the process needs to keep moving forward. The men and women of the U.S. Postal Service have waited long enough for safer, cleaner vehicles to fulfill on our universal service obligation to deliver to 161 million addresses in all climates and topographies six days per-week.”

The USPS said it determined that its preferred alternative vehicle from Oshkosh “is the most achievable” because a battery electric (NGDV) vehicle has a significantly higher total cost of ownership than the gas-powered one. The USPS said this is why the agency will not commit to having more than 10% EV vehicles in its fleet.

The decision was rebuked by the Biden administration and various pro-EV groups, including the Electrification Coalition. 

“It’s beyond disappointing that the USPS has ignored the justified criticisms of its opaque and flawed environmental impact analysis and committed to an overwhelmingly gas-fueled new fleet,” Electrification Coalition Executive Director Ben Prochazka said in a statement.

The USPS began searching for replacement vehicles in 2015. This next-gen vehicle would need to have improved ergonomics, be equipped with air conditioning and heating, and have advanced vehicle and safety technology such as 360-degree cameras, advanced braking and traction control, air bags and a front- and rear-collision avoidance system that includes visual, audio warning and automatic braking. The vehicles also had to have increased cargo capacity.

Last year, USPS announced it had awarded Oshkosh Defense the contract. Lordstown Motors, the EV startup turned troubled publicly traded company, lost out on the contract.