Energy-saving ALS compressors offer precise power when needed

Precise, power-saving frequency-controlled marine compressors are being supplied for a series of LNG carriers under construction in South Korea that will be equipped with air lubrication systems (ALS).

Oslo-based TMC Compressors has been contracted by shipbuilder Hyundai Heavy Industries (HHI) to supply the marine ALS compressors for four 174,000-m³ LNG carriers under construction for Seoul-based shipowner Pan Ocean. The four newbuilds will be under long-term charter to Shell for seven years, once they are delivered in 2024. Each LNG carrier will be equipped with HHI’s self-developed Hi-ALS air lubrication system.

ALS, which has become increasingly popular for use on LNG carriers, reduces the friction between the ship’s hull and seawater by distributing microbubbles across the underside of the ship, reducing fuel consumption and greenhouse gas emissions.

TMC has developed a range of frequency-controlled marine compressors for use in combination with ALS. In the case of the Pan Ocean newbuilds, TMC will supply three ALS compressors for each LNG carrier. The 12 ALS compressors will then be coupled with HHI’s Hi-ALS system.

“We have only seen the tip of the iceberg for the adoption of ALS technologies”

These newbuilds are among a total of five 174,000-m³ LNG carriers being built for Pan Ocean. Besides those for Shell, the fifth LNG carrier is fixed with Galp for five years, with delivery targeted for February 2023.

Additionally, Pan Ocean is building an 18,000-m³ LNG bunkering vessel that will go on charter to Shell for six years when it is delivered in May 2023.

“ALS is about reducing fuel consumption, energy costs and emissions to air,” says TMC director of sales and business development Hans Petter Tanum. “It is a great way of reducing the shipping industry’s environmental footprint while also reducing shipowners’ opex,” he adds.

TMC’s frequency-controlled ALS compressors also offer fuel savings compared to conventional compressors. As the frequency-controlled technology offers precise control of the compressor speed, the speed of the electrical motor will adjust itself according to what is required, producing the exact air volume necessary to meet the actual compressed air consumption at all times. In turn, lower air consumption requires less speed on the compressor, and this directly results in less power consumption.

“We have supplied several ALS compressors to HHI in the past two years, but so far we have only seen the tip of the iceberg for the adoption of ALS technologies,” adds Mr Tanum. Inquiries for ALS compressors have increased significantly in the last 18-24 months, said the company.

The equipment for this most recent order will be manufactured in Scandinavia and shipped to HHI.

TMC offers compressors for ALS applications that ranges from 50 kW to 400 kW capacity, plus the associated ALS control system.