In an effort to curb pollution, cruise ports all over the United States are opting to allow ships to switch from diesel powered engines to shore side power while they are harbored. The ships can plug in to the shore side power docks and this will prevent the ships from running their diesel engines and polluting the port side waters.
While this may not be the ultimate solution for pollution, there are a good number of ports all over the United States that are using this system. This is seen as a step in the forward direction.
When a ship plugs in to shore side power, the diesel engines of the ship do not have to be powered. This will reduce polluting the ocean side atmosphere and water. The ship connects to the electrical grid of the city to power its systems on board.
While the ship is connected to the power grid, there is very little fuel emissions taking place. This is seen as a definite advantage. Juneau was the port that first offered this service in 2001. Seattle can next. Vancouver joined in 2009. San Francisco, San Diego and Los Angeles were the latest additions from California.