Are air lubrication systems both sustainable and profitable?

The concept of air lubrication has been here for a couple of years. The method is used to reduce the resistance between a ship’s hull and seawater. In a myriad of projects within the maritime industry, the technology has proven to be useful in cutting fuel consumption and CO2 emissions.

However, many shipowners are faced with a profitability dilemma regarding such systems, especially in light of post-pandemic financial woes that are hurting the shipping industry.

Denmark-based green tech business Njord decided to throw air lubrication systems into play as both sustainable and profitable ventures in its new panel ‘Air Lubrication Systems: Investing in Sustainability and Profitability’ hosted on November 15.

The event gathered industry experts to discuss how shipowners could leverage this technology within their fleets, combined with traditional methods, to improve financial performance while reducing carbon emissions.

In brief, the concept of air lubrication for vessels is the introduction of a layer to reduce the friction between the hull and the water, thus, creating an air cushion that decreases the drag of the vessel, improves fuel efficiency, and cuts emissions.

At present, there are several air lubrication technologies tested. They include air lubrication systems, air cavity ships, winged air inject pipe, and air chamber energy savings.

There are a total of 65 installations of air lubrication technology currently in the water and about 200 orders in the book, the event moderator informed, referring to installation statistics of the four air lubrication providers participating in the event.

The panel discussion highlights that the return on investment (ROI) is dependent on the following factors:

• ship type;
• ship operation;
• ship utilization;
• fuel that a ship uses and
• carbon tax and emissions trading systems (ETS).

“We believe that anywhere between nine months and up to three and a half years is the payback period that we have assessed,” Alex Routledge, CEO of Armada Technologies Limited, revealed.

The assessment is based on Armada Technologies’ sensitivity analysis for a range of different ships taking input directly from shipping companies.

UK-based Armada Technologies is developing the world’s first naturally aspirated air lubrication system or passive air lubrication system. In contrast to existing solutions, Armada’s system operates in a semi-passive mode and enables discreet control of system output with the complete decoupling of system lubricity from ship speed. In doing so, Armada said it can deliver optimal boundary layer aeration at any prevailing operating condition. 

Last year, Armada entered into a collaborative agreement with US provider of ballast water treatment systems Ecochlor for the technical assistance and global sales and marketing support.

Armada Technologies will have its first installations of the system next year and has several potential orders subject to contract in early 2025. Armada’s main ambition is to prove its relatively new technology.

Another air lubrication technology provider, Sweden’s Alfa Laval, shared its findings at the panel, with Frode Lundsteen Hansen KCHS, Regional Business Development Manager, Asia & Nordics, Alfa Laval Aalborg noting:

“The ROI depends really on the ship’s operational profile but we are definitely below five years, typically three to four years.”

He added that savings amount to up to 11%.

Currently, the Swedish sustainable solutions player has ten ongoing installations of its air lubrication system since the debut installation carried out in 2020. Four more installations are coming up in the next few months.

Based on fluidic technology, AlfaLaval OceanGlide integrates fluid technology into air lubrication to optimize energy savings. This system uses fluidic oscillators to generate an even layer of micro-air bubbles across the vessel’s flat bottom, reducing friction and drag. 

The UK’s cleantech company, Silverstream Technologies, which is ‘mature’ in this segment, also presented the benefits of its system to the panel audience:

“We’ve been consistent in messaging to promise and deliver somewhere between 5 and 10% net savings,” Craig Patrick, VP of Sales at Silverstream Technologies, said.

Touching upon ROI, Patrick explained that the payback and ROI would vary depending on the vessel type — an LNG carrier, a cruise ship, Ro-Ro or container vessel. Therefore, it is specific for each customer.

Silverstream has completed installations of 53 vessels operating in multiple segments and has 180 orders.

“From the 180 orders that we have, we have managed to achieve ROI expectations of those specific customer needs,” Patrick elaborated.

Silverstream System shears air from air release units (ARUs) in the hull to create a uniform carpet of microbubbles that coats the full flat bottom of a vessel. As a result, frictional resistance is decreased — reducing fuel consumption and associated emissions. 

The final panelist was Dutch Damen Shipyards Group which recently secured the first sale of its air lubrication system Damen Air Cavity System (DACS).

The system maintains a thin layer of air over the flat bottom of a vessel’s hull, reducing resistance in the water, and thereby lowering drag and friction.

Under the first deal, the system was retrofitted to Estonian-based shipping company Amisco’s cargo vessel Danita in Tallinn, Estonia.

Apart from Danita, Damen’s system has been installed on one more vessel, an inland bulker ship newbuild.

Although Damen Shipyards Group is relatively new in the air lubrication segment, the company also shared interesting information on the profitability of its system.

Following the sea trial of Damen’s air lubrication system onboard Danita, the company concludes that there is a “saving for this ship of up to 78% which means in their case it’s an ROI of two years approximately”, according to Herman Thuss, Business Development/Sales Manager at Damen Green Solutions.

Currently, Damen Shipyards Group has four more ships in contract.