How cost-efficient & sustainable is the recycling of transformer oil?

In particular after repair and maintenance work on transformers or on-load tap-changers, many companies use recycled transformer oil - instead of new oil. Read on to find out more about transformer oil recycling and how you can be sure that you are choosing the right insulating oil.

Sustainable asset or plant management is becoming more and more perceived as a decisive value-added factor in companies. This is due to both general cost pressure and legal requirements regarding environmental protection. The importance of supply chain issues and dependence on the countries of origin of crude oil is also increasing. In this context, regulatory developments such as the EU Circular Economy Act are also becoming increasingly important for the transformer industry.

In addition, transformers must have a longer service life than before and operating costs from energy, material and personnel should be reduced to a minimum. 

Recycling of transformer oil is a cost-efficient alternative

The economic handling of transformer oil has also become a cost factor in the optimisation of plant management. Because producing recycled transformer oil is far less energy-intensive. No crude oil has to be extracted and transported from overseas or over long distances. 

As a result, the costs of recycled insulating oil are lower than those of new insulating oil and are not directly subject to fluctuations in the market price of crude oil. 

Recycling of transformer oil is an image-enhancing, sustainable initiative

The benefits for the environment should also be emphasised. After all, it is important to avoid wasting valuable insulating oil. And those who decide to recycle transformer oils are thus deciding in favour of a greater sustainability focus for their company.

Already today, more than 60,000 tonnes of transformer oil are recycled annually in the Benelux countries, Germany, France and Great Britain. In the interest of sustainability and resource conservation, you too can reduce oil-containing - and thus hazardous - waste in your company!

When is recycled transformer oil the right choice?

For procurement managers, the question is not so much whether, but when, the use of recycled insulating oil makes sense. Typical applications include:

• Following maintenance and repair work, for example on transformers or tap changers, when insulating oil needs to be replaced or topped up
• For larger fleets of transformers, to optimise costs in the long term
• When delivery times for new transformer oil are critical
• As part of sustainability targets or ESG requirements

Particularly in standardised applications, recycled transformer oil offers an economically and technically equivalent alternative to new insulating oil.

Is the quality of recycled transformer oil the same as that of new oil? Take the following precautions:

1. Transformer oil acc. to IEC 60296 

There are high-quality recycled transformer oils that can compete well with new insulating oils. As long as they meet the requirements of the international standard IEC 60296:2020 for mineral naphthenic insulating fluids in electrical equipment, they are oils with as-new properties. 

2. Expertise of service provider

In addition to the as-new product, the service provider who takes care of the removal of the poor quality transformer oil and replaces it professionally must also be considered.

This involves important questions such as:

• Is the company certified as a specialist disposal company?
• Is it allowed to work with liquids that are hazardous to water?
• How is the quality of  all key processes checked and audited?
• To what extent is the environment taken into account?
• And how is occupational health and safety ensured? 

3. How can you minimise your risk as a buyer?

A common obstacle when deciding to use recycled transformer oil is a lack of technical information. This makes a structured selection process all the more important. Request the following evidence from your potential supplier:

• Compliance with standards (IEC 60296:2020) for the recycled transformer oil
• Batch-specific analyses and test reports
• Transparent documentation of origin and processing
• Clear responsibilities on the part of the service provider
• Testing intervals
• Condition assessment of transformer oil and transformers
• Long-term maintenance strategies

In addition, it is advisable to work with partners who not only supply the product but also provide advisory support, e.g. regarding:

Important standards and certificates when dealing with transformer oil

In other words, make sure to only commission companies that meet the standards and can show the relevant certificates: 

• Transport companies require a Hazardous Waste Carrier Licence: Before used transformer oils are removed from equipment and site, ensure that your appointed service company has the necessary and correct waste licence in place to comply with all local, national and international regulations.

• Recycling companies must have regulatory Waste Management accreditation or Environmental Permit: Recycling is a proven process via proprietry technology undertaken in strict accordance with local and national regulation and accreditation. Ensure your service company has these in place before trusting them to recycle responsibly. Better still choose a company dedicated to recycling the precious resource of insulating oils.

• Quality Management - ISO 9001: This certification specifies requirements for quality management along the entire value chain, formulates a management system and provides companies with suitable measures.

• Environmental Management - ISO 14001: This certification covers all aspects for continuous improvement of environmental performance.

• Occupational Health & Safety - ISO 45001: This standard formulates the requirements for occupational health and safety management systems and provides companies with suitable measures.

Electrical Oil Services (EOS^®) fulfils all the above requirements and produces recycled transformer oils in accordance with IEC 60296:2020 Ed.5 and BS148:2020. 

Get an overview directly on this info page:

• EOS^® brochures and certificates

From waste to resource: The EOS^® Closed Loop Model

The EOS^® Closed Loop Model, developed by Electrical Oil Services, is a structured approach to the sustainable use of transformer oil.

Under this Closed Loop Model, used insulating oil is systematically:

• collected
• reprocessed
• and returned to service as transformer oil  

Instead of simply disposing of or outsourcing the recycling of waste oil, it is thus retained as a valuable resource within the technical cycle.

The benefits for the procurement department:

• Greater cost certainty, as there is less dependence on volatile crude oil prices
• Reduced disposal effort and associated costs
• High security of supply thanks to predictable availability of insulating oil

In this way, a necessary disposal process becomes an integral part of a forward-looking and sustainable procurement strategy. Furthermore, your company thereby supports internal sustainability goals and ESG requirements.

Find out more on this page:

• For a modern circular economy: The EOS® Closed Loop Model

Conclusion: Recycled transformer oil in like-new condition is more cost-effective and sustainable than new insulating oil

Transformer oil has excellent potential for reuse by returning it to the cycle after proper treatment: Recycled transformer oil is used by public utilities and industrial companies especially when transformers are refilled with insulating oil after repair and maintenance work. Our tip: Make sure you have the right certificates with regard to the products and the service provider, and choose a partner who will support you in the long term!

Find out more on this page:

• For a modern circular economy: The EOS^® Closed Loop Model

Do you have any questions on the recycling of insulating oil? We will be happy to advise you.

This article has been published first on February 14 2023. 

EOS Trusted Purity Blog