BP has unveiled the Alaskan Navigator, one of two oil tankers in its operating fleet to be retrofitted to use shore-based electrical power when it is at berth.

The 2005-built 193,048 dwt double-hulled suezmax crude oil tanker called at the Port of Long Beach on Wednesday to become the first tanker in the world to plug into a dockside electrical outlet, reported California's Press-Telegram. The practice is commonly referred to in the industry as cold ironing.

“It was difficult, challenging and ultimately quite costly, but worth it,” said Roger Brown, a BP executive during a welcoming ceremony for the Alaskan Navigator at BP's oil terminal at Pier T in the Port of Long Beach.

“There's really no price you can put on benefits in air quality and people's health,” he added.

It reportedly took some five years and $24 million to design and build the dockside power outlet at Pier T.

The cold ironing facility was made available through engineers constructing a million-pound underwater outlet anchored by a series of 168-foot concrete pilings and holding a massive steel cable that connects to the ships.

The Alaskan Navigator is said to burn some 10,000 gallons of diesel (33.3 metric tonnes) per day at berth in order to power “massive pumps” needed to discharge its crude.

According to Long Beach Harbour Commission president Jim Hankla, engineers from other ports have visited to study what he described as an “engineering marvel”.

The Pier T cold ironing facility is slated to handle up to three cold-ironing enabled tankers per month, which will reportedly cut nitrogen oxides (NOx) emissions equivalent to 187,000 cars during each call.

Similar efforts are said to have been introduced at three box terminals in Long Beach and its twin Port of Los Angeles, and several more are reportedly on the cards to come on-line next year.

It is believed that cold ironing is more crucial for oil tankers than any other type of vessels as much more power is needed at berthing for loading and discharging operations.