During the 1990s and early 2000s, considerable corporate planning and investment went into designing processes and facilities that turn certain feedstocks into Group II grades. Some believed these oils could cater to the future of finished lubricants across all applications, from automotive to process oils and from hydraulic fluids and gear oils. Some even believed they could function well in the marine lube space, a traditional stronghold for Group I materials.

This drive into new technology was led by oil majors such as Shell, ExxonMobil and Chevron. They aimed to achieve global acceptance and approvals for specific Group II oils that could be interchanged between one producing facility and another.

With production hubs in the United States and Asia, Group II made inroads into existing Group I markets in those regions. Meanwhile, Europe lagged behind by not having any large indigenous supplies for the newest generation of Group II base oils, and was instead an importer of U.S. and Asian stocks. There had been some small-scale production of certain oils in Europe that were designated Group II, but effectively these grades only qualified on the basis of a higher viscosity index.

Initially, Group II production took place in existing Asian and American refineries that had undergone facility upgrades. This, it was felt, was the most efficient and cost-effective method of converting existing Group I solvent extraction units into new technology, sometimes incorporating de-isomerization, using specific feedstocks produced at the source refinery.

By the mid-1990s, several new Group II units had been commissioned, first in South Korea and China, then in the U.S. and eventually in Europe. It was not until 2019 that Europe would see the construction of a world-scale production unit for these base oils, when the ExxonMobil facility in Rotterdam was brought on stream in February this year.

Commercial acceptance and the transfer to Group II was relatively smooth in most advanced markets. Although, initially some players recognized that there could be limitations due to the lack of high-viscosity Group II grades, which were deemed necessary for particular applications where a higher total base number and heavier base stocks were required.

These obstacles were secondary to the range of Group II base oils available at the time having the benefits of mitigating emissions when used in automotive applications due to a higher V.I. and a lower Noack value, which reduce oil loss. And, although Group III base oils would still have additional roles to play, Group II stocks had a wider application base on which to rest.

In some traditional markets – Europe being one of them – there was still an option to use Group I for specific applications where higher viscosities were required. Group I refineries were and are still functioning, many of which either belong or had belonged to European national oil companies. These refineries were existing, older units that would not or could not be upgraded to accommodate the new generation of base stocks.

Whilst importing Group II base stocks in large quantities, Europe remained until recently both a domestic user and export center for Group I. Much of this material is still being moved to markets in West Africa, the Middle East and India, all of which are the last Group I bastions for the production of all types of finished lubricant, from automotive to transformer fluids and industrial oils.

The evolution of Group II is perhaps reliant on two main factors. The first was the progressive run-down and eventual abandonment of Group I production, due mainly to the age of plants producing these grades coupled with the economic arguments for ploughing in endless capital to keep these facilities running.

The second main driver was ever-growing environmental concerns regarding the control of emissions from diesel and petrol engine vehicles. The advent of mandatory emission limits imposed by intranational and governmental bodies meant original equipment manufacturers and lube blenders had to find a material that could cope with newer performance demands and contribute to lower emissions. They also had to cope with other technologies such as catalytic converters and exhaust gas treatment devices.

One solution to these challenges was to use Group II, which could be incorporated into reworked formulations and specifications for next-generation finished lubricants. With excellent Noack properties, lower sulfur and aromatic content, high V.I. and light color, these oils admirably fit the bill to provide products that could handle a wide range of operating temperatures and have superb cold-start properties.

It would be safe to say that Group II oils are here to stay for the long term. And whilst further progress may be made for some specific finished lubricants using the other higher grades of base oils – from Group III and III+ to Group VI – the ability of Group II to cover a wide spectrum of blending requirements puts it in very strong position.

The obvious fact that several major oil companies have invested billions of dollars in facilities to produce these grades on a global scale is testament unto itself.

The unstoppable move toward cleaner transportation, with growing numbers of hybrid and electric vehicles on the worlds roads, could potentially alter the emphasis for Group II base oils. Although, the current speculation is that whilst lubrication needs may change, the basic requirement of being able to protect two moving surfaces remains part of the challenge for this century and beyond.