Foss Maritime and Aspin Kemp receive US patent for hybrid marine propulsion and energy management system used in harbor tugs
Foss Maritime Company and Aspin Kemp & Associates (AKA) with their technology partner XeroPoint Energy, have received US patent protection for their hybrid propulsion and energy management system. (Earlier post.) Foss, which owns and operates one of the largest tug and barge fleets on the US West Coast, partnered with AKA, a Canadian system integrator and marine engineering company, in developing this technology.
|System schematic. Click to enlarge.|
The hybrid propulsion and energy management system has been proven to significantly reduce emissions, fuel consumption and equipment maintenance for marine vessels. The award-winning hybrid technology draws energy from various sources to optimize system operations across a wide range of propulsive load demands.
Diesel engines are designed to optimally perform at or near their full load design point. However, many marine vessels operate under variable load requirements. Our system provides operators with the flexibility of a diesel electric system and the simplicity of a conventional system, without the cost or footprint of a traditional full diesel electric installation.—Paul Jamer, VP of Corporate Development at AKA
The powerplants in conventional tugs are designed to operate full out, but typically run there less than 3% of the time; for the rest of the time, they are near idle. The design of the hybrid system takes into account the varied duty cycle of the harbor tug.
|Harbor tug duty cycle and design points. Source: AKA and Foss. Click to enlarge.|
Foss built the first hybrid tugboat, Carolyn Dorothy, and has successfully converted a second vessel, Campbell Foss, to a hybrid at its shipyard in Rainier, Oregon. Both of these vessels use the AKA energy management system to provide Green Assist tug services to customers in the Ports of Los Angeles and Long Beach, California.
The hybrid propulsion and energy management system is patented under US Patent 8,062,081 and additional international patents are pending.
The Hybrid Solution; Power And Reliability In A Green Package (Foss and AKA presentation at 2012 Greening the Research Fleet workshop at Duke University.)