UPS plans to invest $450 million over the next three years to purchase more than 6,000 natural gas-powered trucks in a move aimed at improving the sustainability of its fleet.

The new vehicles would be equipped with compressed natural gas (CNG) fuel systems provided under an agreement with Agility Fuel Solutions. The CNG systems may be used interchangeably with conventional gas and renewable natural gas (RNG), which is produced from landfills, dairy farms and other sources.

The agreement expands UPS’ relationship with Agilityl, which has provided natural gas fuel storage and delivery systems to more than 1,700 UPS trucks since 2016. Starting next year, Agility would provide fuel systems for heavy-duty trucks, terminal tractors and the familiar brown medium-duty walk-in vans that deliver packages across the country.

Over the last decade, UPS has invested more than $1 billion in alternative fuel and advanced technology vehicles and fueling stations to help meet its goal of reducing greenhouse gas emissions by 12% across its global ground operations by 2025. The company has agreed to purchase 230 million gallon equivalents of RNG over the next seven years.

The new gas-powered trucks would be strategically deployed to utilize CNG fueling stations UPS has constructed or added to existing gas fleets in various UPS locations. By the end of the year, the company said it would be operating 61 natural gas fueling stations across the United States Canada and UK.