Cruise ships that dock at the Embarcadero in downtown San Diego are now able to turn off their engines while in port, and plug into power on shore. San Diego is the second port in California to install a system that radically cuts pollution from cruise ships.
More than 220 cruise ships pulled into San Diego Bay last year, and spent several hours moored at the Embarcadero downtown.
David Merk of the Port says they used to have to keep their engines running in order to keep the lights on.
"We estimate that a ton of air emissions are discharged by a cruise ship every time that it pulls in to San Diego," he said. "So this allows us to have them operated by electricity rather than by their normal power source."
Plugging in to electricity on shore is called "cold ironing." The system cost the Port $7 million, but part of that was covered by a state grant of more than $2 million.
By 2014, all cruise lines will have to use shore power for at least 50 percent of their ports of call.