As the workday begins at the Port of Tacoma, the engines start.  

Members of the International Longshore and Warehouse Union Local 23 drive giant straddle carriers from their parking spots to the North Intermodal Yard, where they’ll move containers coming and going by ship. 

“Pretty much anything that touches containers that's not electric is running mostly off of diesel,” said Rick Atkinson, the Port’s director of equipment maintenance.  

In May, the Port began using a renewable diesel called R99, a drop-in fuel that can run in any diesel engine without equipment retrofits.  

“You just make the choice today, put it in your tank, and you’re on your way to reducing your carbon footprint,” said Laura Yellig, President and CEO of Petrocard, one of the largest fuel distributors in the Northwest. 

R99 stands for 99% renewable. 

While it’s made from the same materials as biodiesel, like used cooking oil and animal fats, the manufacturing process is different. 

“I consider it the more refined sibling of biodiesel,” Yellig said.  

Renewable diesel is made in refineries to be chemically identical to petroleum diesel, allowing it to be easily blended at any percentage. 

Compared to traditional diesel, renewable diesel looks like water. 

More importantly, it burns much cleaner. 

“Depending on the fuel source, it can offer a 60 to 75% reduction in lifecycle greenhouse gas emissions and about a 20 to 30% reduction in particulate matter,” said Rose Arsers, environmental project manager at the Port of Tacoma and The Northwest Seaport Alliance. 

In 2023, Port of Tacoma Commissioners voted to reduce greenhouse gas emissions under the port’s direct control to net zero by 2040, accelerating the target by a decade. 

The Port and NWSA are adding electric vehicles and yard trucks, encouraging greener short haul trucks, and installing shore power at more container terminals. 

In June 2024, a new report showed Puget Sound maritime-related greenhouse gas emissions down 10% between 2005 and 2021. 

 “We are making the major investments today so that when we have this press conference in ten years, you will see the results,” Port of Tacoma Commission President Kristin Ang said at an event releasing the report. 

While electric alternatives for big, specialized equipment are developed, renewable diesel is a good fit. 

“It’s a good strategy to reduce emissions until the zero emission strategies are feasible,” Arsers said.  

Atkinson said because R99 burns cleaner, exhaust filters don’t get clogged, reducing the Port’s maintenance costs. 

“It makes the equipment run better,” Atkinson said.   

Incentives in the state’s clean fuel standard mean that supply is up and the price is now in line with conventional diesel. 

According to Petrocard, so far, one of Washington’s five refineries is blending in renewable diesel, which is mostly brought in from other states by barge or train.  

Until it becomes widely available, fleet customers like the Port of Tacoma are getting a head start, making the switch to greener diesel.