Golden Gate Ferry Commissions 10-Megawatt-Hour Floating Battery Barge and Pantograph Charger at Larkspur Terminal

Marine engineering directors with the Golden Gate Bridge, Highway and Transportation District and clean-maritime specialists from the California Air Resources Board commissioned a 10-megawatt-hour (MWh) floating lithium-iron-phosphate battery energy storage barge and an automated 4-megawatt overhead pantograph charging arm on Sunday afternoon at Berth 1 of the Larkspur Ferry Terminal at 101 East Sir Francis Drake Boulevard in Marin County. Serving the flagship 30-minute transbay commuter route between Larkspur and the San Francisco Ferry Building, the floating energy buffer enables high-speed battery-electric and plug-in hybrid catamaran ferries to recharge during fifteen-minute passenger boarding turnarounds.

Because drawing a sudden 4-megawatt power spike directly from the local Marin distribution feeder during every ferry docking would require a multi-year onshore utility substation rebuild, engineers housed ten liquid-cooled marine-certified LFP battery racks inside the double-hulled steel boarding float itself. The barge draws a steady, low-power 650-kilowatt trickle charge from 100 percent renewable MCE Deep Green shore power throughout the day and night, then discharges at up to 4,000 kilowatts DC through an automated robotic mast arm the moment a ferry moors.

Laser optical alignment sensors on the dockside charging tower mate with the vessel's bow receptacle in twelve seconds, delivering 950 kilowatt-hours of propulsion energy while passengers walk off and on the gangway. During an earthquake or Marin grid blackout, the 10-MWh barge can also back-feed emergency power to the entire Larkspur terminal and SMART rail pedestrian bridge.

The $11.6 million maritime charging float was funded through a Federal Transit Administration Passenger Ferry Grant and California Cap-and-Trade Low Carbon Transit Operations funds. Riders can view transbay sailing schedules on the Golden Gate Ferry Official Portal.