The South Pasadena Police Department in California unveiled its all-electric police fleet on July 29, becoming the first law enforcement agency in the nation to completely replace its gasoline-powered vehicles with electric vehicles.

The department announced that it would be rolling out all-electric fleet consisting of 20 Teslas, including 10 Model Ys and 10 Model 3s, according to a press release.

“This transition reflects the city’s vision of a sustainable future based on both sound fiscal management and environmental stewardship,” South Pasadena Mayor Evelyn Zneimer said during a news conference. “We will have a 21st-century police force that is safe, clean and saves taxpayer dollars.”

According to city officials, the transition is expected to save about $4,000 a year per vehicle on energy costs, and generate savings on maintenance such as oil changes, brakes and air filters, the news release said. The overall operational cost per mile will be at least half of what it was previously with gas-powered vehicles, according to Police Chief Brian Solinsky.

“Switching to these vehicles offers the police department the opportunity to acquire a cutting-edge vehicle fleet,” Solinsky said. “This initiative not only ensures the safest vehicles for officers and staff but also leads to substantial reductions in both fuel and maintenance costs.”

Police have been hesitant about electric vehicles because of concerns about “range, potential inability to charge when the grid goes down, and worries that the technology is new and unproven,” the release stated.

To address those drawbacks, the project includes 34 electric vehicle chargers at South Pasadena City Hall, plus solar panels and battery storage in case the grid fails.