Why biodegradable hydraulic lubricants are becoming a sustainable choice?

Every day millions of machines across the globe—excavators ploughing into hillsides, tractors moving across farms, offshore drilling rigs that protrude from the ocean—depend on hydraulic systems to perform their duties. They rely on hydraulic fluids in order to transfer energy, supply power to moving components, and disperse heat. For the majority of the last 20 years of this century, the fluid was in one shape: mineral oil, which is derived from petroleum.

It worked. It continues to work. However, it comes at a price that the industry is just beginning to fully comprehend.

Conventional mineral-based hydraulic oils remain environmental pollutants. One liter of hydraulic oil could contaminate up to 1 million liters in groundwater. In the world, it is believed that up to 50% of the oil-based lubricants are disposed of in the earth's environment due to spills, leaks, equipment failures, or the wrong disposal. If a business is operating near forests, rivers, agricultural land, or marine habitats, the effects could be catastrophic: contamination of soil, corroded ecosystems, waterways that are disrupted, and significant legal and regulatory responsibility.

This is the challenge that biodegradable hydraulic lubricants have been developed to solve.

How do you know if biodegradable hydraulic oils?

Biodegradable hydraulic lubricants are designed to naturally break down in the natural environment by the activity of microbial organisms, which reduces their environmental footprint when compared with conventional petroleum-based options. They typically originate from one of three categories of base stock:

Vegetable oils (HETG) are derived from sunflower, rapeseed, soybeans, or other plant sources. They are the most easily biodegradable and are frequently used in forestry and agriculture as well as freshwater habitats. Rapeseed oil, specifically, is now among the top commonly used bases because of its superior lubricity as well as availability.

Synthetic esters (HEES) are esters that have been synthesized and offer higher performance across a greater temperature range and longer service lives than vegetable oils. They are biodegradable and are highly recommended for demanding marine and industrial applications where performance demands are very high.

Polyalkylene Glycols (HEPG)—Water-soluble synthetic fluids that possess good biodegradability as well as thermal stability. They are especially suited for environments that are sensitive to fire but need strict checks of compatibility between the materials.

Each type provides a unique blend of biodegradability and efficiency and price, which gives sustainability managers a lot of flexibility when matching the appropriate fluid for the task.

The environmental case: More than just marketing

If we are to say that a substance has the ability to be "biodegradable," we need accuracy. In the world of lubricants, biodegradability is assessed through standardized tests, typically the OECD 301B test, which measures the extent to which the substance is degraded within 28 days in aerobic conditions. Fluids with more than 60% degradability in the test are categorized by the OECD as "readily biodegradable."

A lot of modern biodegradable hydraulic fluids have 70-99% degradability within this timeframe. Contrast this with traditional mineral oils, which usually have a score of less than 30%, which means that the majority of the oil remains in the soil for many decades.

Beyond the biodegradation rate These fluids also provide less toxicity to the aquatic environment. The regulatory frameworks, such as those of the EU's Water Framework Directive and Germany's WHC (Water Hazard Class) system, are beginning to reflect these facts, and biodegradable liquids are becoming more often classified in lower risk categories. This is particularly important for those operating close to protected waterways, as an accident involving a highly hazardous fluid could result in cleanup costs and legal ramifications that are far more costly than changing the type of lubricant.

For the industries of marine construction, forestry, tunneling, agriculture, and marine construction that are in contact with water and soil, it is inevitable; the argument for environmental protection isn't abstract. It's an operational and financial deal.

Performance: Closing the gap

One of the biggest obstacles to adopting green technology has been the belief that greening means taking a chance with inferior quality. This was certainly the case in the past. The first vegetable oil-based fluids had to contend with the oxidative stability (they rapidly degraded in service) as well as the limited operating temperatures and the susceptibility of microbe contamination.

Biodegradable hydrocarbons that are biodegradable have addressed these issues with great success:

The stability of oxidative and thermal temperatures has been significantly enhanced in the formulations of synthetic esters, with certain fluids now meeting or even exceeding the life span of premium mineral oils as long as 6,600 hours under controlled conditions.

The performance of viscosity across extreme temperatures has been improved, with a variety of HEES fluids delivering solid performance ranging from -40°C to more than 100°C, making them ideal for Arctic forestry and high-temperature industrial applications as well.

The compatibility of seals and other materials has been improved. Some of the first biodegradable liquids resulted in seal swelling or degradation by interacting with certain elastomers. Modern formulations are designed to be compatible with the standard hydraulic system components; however, system audits prior to change are recommended.

Quality of hydraulics—the primary function of all hydraulic fluids—is now excellent in the best biodegradable products available that offer wear protection and film strength comparable to other alternatives.

The performance gap has reduced to the point that many OEMs, including the major producers of construction, forestry, and agricultural equipment, have apprehensions or even recommendations for biodegradable liquids for specific applications.

Regulatory momentum and industry shifts

Regulation is driving adoption in ways that are past voluntary sustainable commitments.

In Europe, the EU Ecolabel for lubricants provides an official certification of products that have met strict biodegradability toxicity and standards for renewable content. The public procurement regulations in a number of EU member states demand or strongly favor eco-labeled oils for contracts with the government. Germany's strict law on water pollution has for a long time driven water users towards biodegradable fluids, and similar laws are now spreading.

The United States EPA's Vessel General Permit imposes on vessels operating within US waters the requirement to make use of "environmentally acceptable oil and lubricants," which is defined as biodegradability and low toxicity to aquatic environments—in the case of interfaces between oil and sea. This has led to a significant increase in adoption in the offshore and marine industries.

Beyond the regulation realm, beyond regulation, corporate ESG (Environmental, Social, and Governance) commitments have a more practical role. In the face of the pressure of insurers, investors, and suppliers to show commitment to sustainability, the choices for lubricants that were previously purely technical are now being incorporated into the conversation of sustainability reporting.

Economic considerations: The full cost picture

Biodegradable hydraulic fluids usually have an upfront cost that is higher than mineral oils that are conventional—typically up to 4 times the price per liter, based on the formula. It is the single most popular argument against adoption and is the right one.

However, the complete price picture of costs is much more nuanced.

Cleanup and spill liability is possibly the biggest cost to consider. The cost of cleaning up the aftermath of a hydraulic oil spill, environmental consultants, regulatory compliance, groundwater treatment, soil, and legal liability could range from tens of thousands to millions in relation to the scale and the location. Biodegradable liquids significantly lower the risk and, in many regions, help reduce cleaning requirements that are mandatory.

The cost of regulatory compliance is rising. Operators who are aware of the stricter fluid regulations can prevent costly mid-project conversions and the possibility of operational shutdowns.

Insurance implications are beginning to change, with a few insurance companies offering lower premiums when they use certified biodegradable fluids in environmentally sensitive zones.

Longer drain intervals in top-quality synthetic ester products may help reduce the cost per liter through reducing the frequency of changing fluids and consequent downtime.

When all these elements are considered together, when they are weighed together, you will find that the cost of ownership of biodegradable liquids tends to be much lower than the cost of the traditional alternatives, particularly in operating environments with high risk.

Applications leading the charge

Biodegradable hydraulic fluids are a trend that is not the same across all sectors; however, several industries are far ahead.

• Forestry and logging operating in clean forest environments which are directly in contact with the soil and waterways. This industry has been among the first and constant adopters.
• Agriculture—Tractors and other farm machinery manufacturers are beginning to accept biodegradable fluids. Organic certification organizations in certain regions need them.
• Marine and offshore Instigated by regulations and the obvious effects of oil spills into the ocean.
• Civil engineering and tunnellingGroundwater-related operations or municipal water supplies are subject to immense pressure to make use of low-risk fluids.
• Hydropower and water management Equipment that is directly in or near water infrastructure is increasingly running on biodegradable fluids, as the norm.

Biodegradable hydraulic oils are not a product with a niche that is waiting for widespread acceptance. They are a well-established, technologically mature product category that the marketplace is slowly moving towards—because of regulatory pressure and environmental accountability, a rise in performance, and a growing awareness of the overall cost of ownership.

The most frequently asked question by industrialists isn't the question of whether to change; however, it is the time and what. In the case of operations that are in locations that are sensitive to the environment, the question of when to transition is becoming more pressing.

The hydraulic fluid that runs through your machine is inaccessible when it is in normal use. When it does leak—or in any mechanical system that has hydraulics, it will eventually—the material it is made of can make a huge difference. In a world where environmental performance is a crucial component of operating performance, biodegradable fluids are not only an eco-friendly option; they are also a smarter choice.