The Ports of Los Angeles and Long Beach, the largest container ports in the nation, are home to the first and only hybrid electric tugboat in the world, and researchers at the University of California have found that this has had a big impact on air pollution.
The diesel electric drive train on the hybrid tug that allows the use of auxiliary power for propulsion was the primary cause for the overall in-use emission reductions as opposed to the batteries, according to the study (PDF).
Tugboats are used to help much larger ships maneuver through the cramped conditions of a busy port. As such, the tugboats are typically powered by marine compression ignition engines that are designed to be extremely powerful relative to the size of the vessel (ENN).
Because these massive engines require a lot of fossil fuel that sends harmful emissions and diesel particulate into the air, the Ports of Los Angeles and Long Beach have become the largest contributors of air pollution in the South Coast Basin according to the California Air Resources Board (CARB).
In an attempt to change this dirty reputation, both ports worked with the South Coast Air Quality Management District to create the Carolyn Dorothy, the first electric tugboat in the world.
The tugboat runs on four diesel engines and 126 batteries and cost the ports and Management District approximately $1.35 million.
ENN reports that after the tugboat’s launch in January of 2009, “researchers from UC Riverside’s College of Engineering Center for Environmental Research and Technology conducted a study to see how much emissions the new hybrid tugboat saved. They found it decreased emissions of soot by 73 percent, nitrogen oxides (smog forming compounds) by 51 percent, and CO2 (greenhouse gas) by 27 percent.”