Tuesday, November 23, 2010

Foss Hybrid Tug Found to Shave Significant Emissions

Researchers at the University of California, Riverside have found that the a one-of-a-kind Foss Maritime hybrid electric tugboat is effective in significantly reducing emissions from tug sources at the Ports of Los Angeles and Long Beach.

Researchers at the UC Riverside College of Engineering Center for Environmental Research and Technology (CE-CERT) demonstrated that the Foss hybrid electric tug Carolyn Dorothy generated 73 percent less particulate matter, 51 percent less oxides of nitrogen, and 27 percent less carbon dioxide than a typically powered diesel tug. The hybrid tug also used 5 percent less fuel than a conventionally powered tug over the eight months of the study.

The Carolyn Dorothy, which took station in Southern California in January 2009, runs on four diesel engines and 126 batteries.

The UC Riverside study was the result of work sponsored by the California Air Resources Board and carried out with the assistance of Foss.

The ultimate goal of the research was to develop and implement a new test protocol that quantifies the benefits of using hybrid technology for a tugboat. For this purpose the researchers chose a side-by-side comparison of two “dolphin class” tugs, one conventional and the other hybrid, operating in the Ports of Los Angeles and Long Beach was performed. The Carolyn Dorothy was the hybrid tug while Foss' Alta June tug with four diesel engines was used as the conventional model.

In addition to the fuel usage and emission reduction, the study also found that the hybrid system increased the average operating load on the auxiliary engine from 12 percent to 34 percent. However, the average load on the main engines was found to be only 12 percent of the maximum rating. The study concluded that hybrid engines are still operating in an inefficient zone, which suggests "the need for a larger energy storage system and smaller main engines in the next generation of hybrid tugs."