Port of San Diego to Deploy Bonnet System to Help Reduce Cargo Vessel Emissions

Clean Air Engineering-Maritime
Clean Air Engineering-Maritime
Clean Air Engineering-Maritime operating a Marine Exhaust Treatment System bonnet at the Port of Los Angeles. Photo: Clean Air Engineering.

The Port of San Diego said May 19 that it’s moving forward with a system to control and capture cargo vessel emissions, also known as a bonnet. The port’s bonnet will be available for use by cargo vessels that aren’t yet equipped to connect to shore power.

In support of the port’s new Maritime Clean Air Strategy, San Diego’s Board of Port Commissioners has approved an agreement with L.A.-based Clean Air Engineering – Maritime, Inc. (CAEM) to design, build, and operate a barge-based emissions control and capture device known as the Marine Exhaust Treatment System, or METS.

For vessels that aren’t yet shore power compatible, the METS places a bonnet over the vessel’s stack to capture and treat exhaust while the ship is at berth.

“Shore power allows vessels to plug-in to shore-based electricity so they don’t have to run their diesel engines while at berth. Having a bonnet in addition to shore power at the Port of San Diego’s cargo terminals – one at the Tenth Avenue Marine Terminal and one coming soon at the National City Marine Terminal – will help to further reduce certain air pollutants like nitrogen oxides and diesel particulate matter,” the port said in a statement.

“The bonnet will give some of our cargo carriers a great option in reducing their air quality impacts while they work to transition their vessels to being shore power compatible,” Port Commission Chairman Dan Malcolm said. “This is another example of how we can maintain and grow our maritime business – and protect jobs – while also improving air quality and quality of life for all who live, work and play on and around San Diego Bay.”

The total cost of the project is about $11.5 million, with the port directing $4.9 million in grant funds received from the California Transportation Commission (CTC). CAEM is covering the rest. The bonnet system is anticipated to be operational by January 1, 2025.

By Mark Edward Nero