The energy to move a cruise ship through the water is the biggest draw on fuel, but the second biggest is often overlooked and is getting major changes on both modern and existing cruise ships.
Cruise ships are more streamlined and fuel-efficient than ever before. From specialized paint that allows them to cut through the water more easily to streams of bubbles along the bow to cut fuel costs, cruise lines are finding ways to get more out of every drop of fuel.
The biggest part of fuel consumption on a cruise ship comes from the propulsion itself. It takes a lot of energy to spin those blades and get a 150,000 gross ton vessel moving at 20+ knots.
But there’s another energy hog that is second only to propulsion and it’s constantly in use all over the ship: the ventilation system.
The size and constant use of a cruise ship’s heating, AC, and ventilation systems make it the second-largest consumer of energy on board.
According to Halton, a company that specializes in indoor air solutions, ventilation on a large cruise ship accounts for 30% of energy use. This could mean as much as 250 tons of fuel each day on a mega ship.
So, as you can see, there’s a big reason cruise lines want you to keep your balcony door closed and try to cut off power and air circulation to the cabin when you’re not present.
Why Ventilation Uses So Much Energy
Think about the sheer amount of power that’s needed for things we take for granted around the cruise ship:
- Constantly supplying fresh air to thousands of cabins.
- Extracting air from a number of galleys where meals are cooked around the clock.
- Maintaining comfortable air quality in theatres, lounges, and dining rooms.
If you ever saw a cruise ship being built, you’d see the huge network of ducts running all over the place. These systems are in constant operation, moving, filtering, heating, and cooling massive amounts of air.
What Cruise Lines Are Doing to Reduce Energy Costs on Existing Ships
Typically, these ventilation systems operate continuously, 24/7, regardless of whether a cabin is occupied or a galley is in full swing. It’s like running your home HVAC system at full blast all the time – not the most efficient method.
Cruise lines are now looking to retrofit existing vessels with more efficient systems, like demand-driven ventilation. Often this is part of the dry dock upgrade that doesn’t get much attention online.
Some companies are testing systems for cruise ships that use a “demand-drive” approach. The smart systems use sensors to detect when and where ventilation is needed on the ship and adjust the airflow.
Here’s how it works in practice:
- Smart Galleys: Infrared sensors in cooker hoods monitor cooking activity and adjust exhaust airflow in real-time, only using maximum power when needed.
- Efficient Cabins: Occupancy sensors detect if anyone is in a cabin and adjust the air supply accordingly. Sensors on balcony doors prevent wasted energy by reducing cooling when the door is open.
The Results? (Especially for Retrofitted Ships)
According to one CEO, these systems can cut overall fuel consumption by 10%. For a large cruise ship burning 150-250 tons of fuel daily, this is a huge reduction in cost. Whether or not this cost will turn into lower prices for passengers remains to be seen, but any reduction in waste should be seen as a positive sign for the cruise industry.
New, strict regulations from the IMO and EU are forcing cruise lines to boost energy efficiency across their existing fleets. Aging ventilation systems on some older cruise ships is something also driving the push for these demand-driven systems
