What weighs in at 122,000 tons, travels about 25mph, carries more than 4,000 people and is green all over?

Celebrity Equinox, the world’s newest and most environmentally friendly cruise ship, is today welcoming hundreds of specially invited guests to tour her decks while the vessel is alongside Southampton’s Western Docks.

The ship, with its distinctive shape, livery and two funnels, is the latest in a new generation of vessels, purpose built in Germany for Celebrity Cruises, which for the past 20 years has been at the forefront of marine conservation with its Save the Waves campaign The second Solstice class vessel to enter service, Celebrity Equinox incorporates highly specialist systems ensuring the luxury cruise ship leaves only a green wake on the oceans of the world.

Sister-ship to the forthcoming Celebrity Eclipse, now under construction in Germany and due in Southampton next year, Celebrity Equinox bristles with equipment designed to cut back on her environmental footprint.

More than 200 solar panels are situated throughout the ship providing power, enough to operate more than 7,000 LED lights, which in turn boost the ship’s electricity grid.

A special silicon coating has been applied to the entire underwater hull area to reduce resistance as the ship moves through the water and to trim fuel consumption. The non-toxic coating also inhibits marine growth such as barnacles and algae and reduces the likelihood of invasive species being transferred from one habitat to other ecosystems.

Celebrity Equinox’s acres of glass are specifically manufactured to reduce heat transfer from outside into cabins and public rooms, which in turn cuts the amount of air conditioning.

The glazing still allows natural light to enter the ship, but filters out 99.9 per cent of UV rays and protects the vessel’s interiors and furnishings.

Advanced purification systems treat all waste water onboard and restore it to virtually drinking quality before discharge.

Even the smallest measures have been adopted to save water consumption, including the use of river rocks instead of ice beds in buffets, shower heads that use less water and reduced-flow dishwashers and low-consumption machines in the galley and laundry.

Celebrity Cruises has also added what it calls an interceptor, which wraps around the ship’s stern, effectively lifting the back slightly to cut the vessel’s drag through the water.

Celebrity Equinox, berthed alongside Mayflower Park, will be officially named in Southampton on Wednesday.

The first ship in her class, Celebrity Solstice, entered service last year.