LONG BEACH has warned that half the ships docked in port must stop using their own engines to generate electricity and plug into local Southern California Edison power grid starting January 1.

Port officials said terminals and shipping lines are spending millions to plug in to local power at berth to cut air pollution ahead of the enforcement of state regulations next year.

Speaking at a "Shore Power Summit", officials said the use of shore power for lights, pumps, communications, refrigeration cuts air pollution by 95 per cent.

The port is completing US$100 million in dockside power hookups, vessel operators are retrofitting older ships for shore power and building new ones as well as installing transmission systems.

The Long Beach Board of Harbour Commissioners hosted the event at the port. New regulations were brought about by the Port of Long Beach and the Port of Los Angeles as part of their 2006 joint San Pedro Bay Ports Clean Air Action Plan (CAAP).