Synthetics offer further indirect energy saving benefits due to their other properties, Reid-Peters continued. For example, the oil in a natural gas engine providing power and hot water to a hospital in California, was switched from a mineral oil to a full synthetic. The synthetic oil extended the drain period from 500 to 3,500 hours, greatly reducing maintenance. The hospital saw U.S. $11,000 savings in maintenance costs, he noted, but this was dwarfed by productivity savings of $65,000 due to increased running time and reduced power costs.

Why Synthetics?

Base oil comprises 30 to 40 percent of the total cost of the finished lubricant, but other significant factors contribute to the cost of a finished product, said David Whitby. Immediate expenses are the base oil, additives and component costs, he told ACIs European Base Oils and Lubricants summit last September in Alicante, Spain. Furthermore, you have to factor in laboratory tests, blending, packaging and storage, as well as distribution, transportation, sales and marketing.

Whitby, who is chief executive of Pathmaster Marketing Ltd., a consultancy based in Woking, U.K., said that end-users have to account for many hidden costs when they ask for a higher performance and added value product. These include formulation, handling and transportation, testing, field trials and approvals, as well as health, safety and environmental testing, monitoring, servicing, collection and disposal.

Generally, formulators in the United States and Europe consider all synthetics to be esters such as polyalphaolefins (PAOs), polyalkylene glycols (PAGs) and polyisobutenes. These regions also consider API Group III base oils to be synthetics, according to Whitby. In Germany, Group III base oils are not considered synthetics, he said, adding the opinion that German formulators have to stop swimming against the current and accept Group III base oils as synthetic products.

Reid-Peters explained, The most common synthetics in terms of consumption are PAOs, esters, polyisobutenes and polyglycols. Each has its advantages and disadvantages, he said, and some can be combined with one another or with mineral oils to provide the best overall performance. For example, PAOs are widely used but have poor solubility and may cause some elastomeric seals to shrink, Reid-Peters noted. To compensate, a small amount of ester is typically blended with PAO to provide solvency and seal swell capability.

Esters, being polar, provide good lubricity and can be tailored to provide good biodegradability. However, Reid-Peters cautioned, good biodegradability means that esters will hydrolyze easily, and they will have poor stability in the presence of water. Alkylated aromatics such as alkylated naphthalene can replace esters to provide similar properties with much better hydrolytic stability, however, at the cost of some biodegradability

In a series of case studies observed by Pathmaster, the consultancy found that cost savings produced by switching from mineral-oil to synthetic lubricants ranged from moderate to enormous. Im quoting information from various sources, some already published and some by companies that asked that their names not be revealed because these numbers are commercially confidential, Whitby revealed. However, I can assure you that these are real numbers.

Automotive Applications

European motorists average driving distance is around 20,000 kilometers per year, with average fuel consumption of 13.45 km per liter, according to Pathmaster. Considering that [in the first half of 2014] gasoline prices amounted to 1.9 per liter and that car owners performed on average one synthetic oil change in two years, they can achieve cost saving of around 75 annually if they use SAE 5W-30 oil instead of 15W-40, Whitby said. This amounts to 3 percent fuel economy. If annual savings in oil purchases and oil changes are added to the fuel saving, total cost saving per vehicle is 160 annually.

The savings can be enormous for an average large European truck fleet operator, which Pathmaster considers to be 100 heavy-duty diesel vehicles or a combination of 40 light-duty, 35 medium-duty and 25 heavy-duty trucks. The trucks consume different amounts of fuel, depending on the driving conditions – in city, short distance or long haul. Light-duty trucks used in-town and for short distances travel about of 20,000 km annually and average around 9 km per liter.

Considering their weight, their larger sumps, medium- and heavy-duty trucks, which are used mainly for long hauls, travel longer distances and consume more fuel. Taking into account such factors as keeping the trucks on the road [fleet productivity], savings in fleet servicing,
the number of oil changes and fuel and engine oil costs, a 100-unit mixed-duty fleet that uses 5W-30 synthetic engine oil could enjoy total annual savings of around 300,000, Whitby said. I think it is a no-brainer.

A large fleet operator with the same number of trucks and the same distances travelled can save even more if it uses synthetic gear oils, according to Pathmaster. Synthetic gear oils can cost significantly more than their mineral counterparts. But taking into account the fuel savings for a fleet that uses 75W-90 synthetic instead of 90W-140 mineral gear oil, total annually savings can be about 180,000, Whitby said. He added that this is on top of the aforementioned 300,000. So, if you are large fleet operator of 100 trucks, why not change to synthetic engine and gear oils? he asked rhetorically.

Industrial Applications

The consultancy found that cost savings can be significant in other applications such as hydraulic systems, air compressors and natural gas compressors if the equipment runs on synthetic instead of mineral oil. For example, a hydraulic system on a mobile digger achieved annual cost savings of about 900 by switching from mineral oil to synthetic hydraulic fluid.

The savings result from doubling the oil drain interval from 6,000 to 12,000 hours, reducing annual oil usage from 250 L/y to 125 L/y, along with related labor costs. Productivity gains are also a factor, which Pathfinder estimated at about 1,000 per year. All these factors add up significantly. If you operate ten mobile diggers, savings amount to 19,000 annually, Whitby observed.

Similarly, an air compressor for a factory pneumatic system can achieve significant cost savings when switched to synthetic oil. An air pumping system with 8,000 working hours annually, sump volume of 30 liters, labor costs of 95/hour, oil change time of 24 hours and factory productivity of 175/hour, can achieve annual savings of about 2,700. In this application, oil change interval can increase from 2,000 to 8,000 hours. Also, annual oil consumption drops to 30 L/year from 120 L/year, reducing labor costs from 1,500/year to 380/year. Interesting in this case study is that the loss of factory productivity drops to zero, which adds significantly to the overall cost savings of 2,700 per year, Whitby said.

One of the most interesting case studies involved natural gas compressors in pumping stations on interstate pipeline networks. This is a case where you really have to use synthetics, Whitby contended. Pathmaster found that if one such facility is lubricated with synthetic oil, the costs can drop from about 220,000 to just 11,000 annually, or 95 percent drop.

This is mainly due to the tremendous increase in oil change interval from 500 hours to 12,000 hours, Whitby noted. The significant increase in drain interval results from the nitration resistance of the synthetic oil. Other savings came from the drop in labor costs for oil changes from about 37,000 to 1,550, a significant decrease in oil consumption, reduced annual oil volume for oil changes, and improved pipeline productivity.

Grease Savings

These cost trends can also be observed in applications that use lithium greases made with synthetic base oils such as PAOs, according to data Pathmaster received from Swedish grease maker Axel Christiernsson. In a paint shop with 25 fans to evacuate the air, annual energy cost savings amounted to 27,000, according to Pathmaster. While savings in energy usage can be important, savings in maintenance, reduced lubricant consumption and enhanced equipment productivity can be more significant, Whitby said.

Pathmaster also found that cost savings achieved by using synthetic oils or greases can vary widely by customer and application. Not all customers may benefit from using synthetic lubricants. I blame this on the resistance to change of some engineers who follow the dictum, If it isnt broken dont try to fix it.

In addition, not all customers can be persuaded of the benefits of using synthetic lubricants because of the simple fact that they are much more expensive lubricants, and saving money by using them seems counterintuitive, Whitby concluded. However, these customers typically are unaware of the total cost of using a particular oil or grease.