Concerns are increasing over stern tube leaks and operational discharges, which were once viewed as routine in marine vessels. A widely referenced study from 2010 estimated that marine shipping vessels leak between 4.6 to 28.6 million liters of lubricating oil from stern tubes annually, while another 32.3 million liters are lost through other discharges and leaks.

In response, environmentally acceptable lubricants (EALs) have been developed to reduce the environmental and wildlife impact of these leaks and discharges. EALs are formulated to meet strict environmental standards, such as biodegradability, non-toxicity, and low bioaccumulation potential. They are commonly used in industries that operate in ecologically sensitive regions, including marine shipping, agriculture, forestry, and construction, where lubricants may directly enter the environment.

Various organizations, including the U.S. Environmental Protection Agency (EPA), the European Union Ecolabel, and the International Maritime Organization (IMO), have established regulatory standards and guidelines for these lubricants. A recent regulatory update, the EPA’s Vessel Incidental Discharge Act (VIDA), aims to reduce the environmental impacts of routine discharges from regulated vessels. While the final requirements are still being finalized, the maritime industry is actively searching for solutions that meet these new performance standards.

While environmentally acceptable lubricants (EALs) offer significant environmental advantages, they also present challenges related to performance, cost, and compatibility when compared to traditional mineral-based lubricants. One key concern is oxidation, as biodegradable fluids tend to be more susceptible to oxidation than conventional mineral oils, leading to faster degradation. Thermal stability is another issue, as EALs can break down more quickly when exposed to high temperatures or extreme heat and cold.

As regulations and market demands increasingly favor sustainable solutions that minimize environmental impact, manufacturers are actively researching and developing hydraulic fluids that meet both environmental and operational needs. For example, Chevron introduced a new biodegradable hydraulic fluid, Clarity Bio EliteSyn AW, designed to address the changing requirements of the marine and construction industries while complying with environmental regulations. This lubricant meets or exceeds government standards for biodegradation, toxicity, and bioaccumulation, and boasts a high renewable carbon content of ≥ 90%.

The fluid underwent rigorous testing, including the Turbine Oil Oxidation Stability Test (TOST), where it was compared against synthetic, zinc-based hydraulic fluids and other EALs and biodegradable products. Results showed that Clarity Bio EliteSyn AW achieved a TOST life of 10,000 hours, separated entrained air in just 2.18 minutes, and had a total water acidity of 3.37 mg/KOH—outperforming its competitors. The fluid is resistant to oxidation under high-temperature operation and resists water contamination, improving system efficiency, reducing the risk of equipment damage, and boosting overall productivity.

“Clarity Bio EliteSyn AW excels in a wide range of demanding applications,” said Zach Sutton, Lubricants Industrial and Services Specialist at Chevron. “It performs exceptionally well in mobile hydraulic systems, offering all the advantages of a traditional product but with enhanced efficiency and productivity, thanks to its bio-based and biodegradable nature. It is capable of handling high-pressure operations exceeding 5,000 psi, making it the ideal choice for operators seeking reliability in tough conditions. Its unique formulation also makes it perfect for servovalves, systems with multi-metal components, and applications requiring high precision. The compatibility and consistent performance of Clarity Bio EliteSyn AW ensure smooth operations without compromising protection or durability, making the transition to this product seamless. Additionally, in marine hydraulic equipment applications that demand specialized solutions, Clarity Bio EliteSyn AW rises to the challenge. Its performance in harsh marine environments demonstrates its versatility and reliability across various industries.”

The new product offers seal compatibility, allowing customers to transition seamlessly without needing to replace equipment seals. This advantage simplifies the adoption process, minimizing downtime and operational disruptions. Additionally, the fluid is low in toxicity to wildlife, making it an ideal choice for applications near water or in areas where wildlife protection is a concern. It meets key environmental standards, including the EU Ecolabel, EPA Vessel General Permit (VGP), Swedish Standard for EALs, and the OECD definition of “readily biodegradable,” ensuring that the majority of the fluid breaks down within 28 days.

Clarity Bio EliteSyn AW is formulated with a 100% renewable, bio-based synthetic base oil, providing all the performance benefits of conventional mineral-based lubricants. It is available in ISO grades 32, 46, and 68.