Power utility Eskom and the Industrial Development Corporation (IDC) signed a memorandum of agreement at a technical workshop at the Eskom Academy of Learning, in Midrand, in September to complete feasibility studies on the adoption and use of natural esters, or vegetable oils, as insulating fluid in electricity transformers.

The agreement covers the testing, validation and development of standards for using a range of vegetable oils, including rapeseed, canola, soya and sunflower oils, in transformers; it also covers the development of a full value chain – from agricultural production to agroprocessing, production, refinement and distribution – for use in transformers of all sizes, said Eskom power delivery engineering GM Prince Moyo.

Eskom research, testing and development GM Barry MacColl noted that the use of vegetable oils in transformers was not new technology and was commonly used in other parts of the world. However, it was new in South Africa and had significant potential to add sustainable, safe and economic value chains to the economy.

Moyo added that natural esters were bio- degradable and had the potential to reduce fire hazards. They also absorbed water better than mineral oils, while initial testing indicated that their use as an insulating fluid would increase the maintenance intervals for larger transformers by two to eight times the current maintenance intervals of transformers.

Vegetable oils could be used as an insulating fluid across the entire range of transformers – from small pole and ground-mounted transformers to large transformers.

IDC new industries head Christo Fourie said the partnership was closely linked with the corporation’s agroprocessing business development initiatives and new industries and businesses could be developed from the application of natural esters in transformers.

“This technology has the potential to expand the local oilseed value chain through addi- tional farming and agroprocessing initiatives. By producing high-value products from renewable, sustainable and environment-friendly inputs, it will ensure a greener electricity industry and also facilitate new industrial development opportunities,” he added.

The technology had the potential to displace four-million litres of imported mineral oil used as insulating fluid, which cost about R88-million a year, and would also create jobs.

IDC new industries senior project development manager Retief Bruwer said the crops that would be used to source the vegetable oils were almost always dry-land crops, which meant that they were not irrigated and would have no impact on water resources.

Soya, in particular, was an excellent rotation crop for cereals, such as maize, that added nutrients back into the soil and would benefit the overall value chain of agriculture. Vegetable oil crops would also enable farmers to add cash-generating crops and improve the sustainability of their cash flow.

Moyo noted that the studies into the use of vegetable oils in transformers would be completed by the beginning of next year, while the specifications for use in smaller transformers would be completed by the middle of next year. The specifications for use of these oils in large transformers would be completed towards the end of next year.

The oils would be subjected to various proprietary refinement processes and would also require various additives, which would be shared with commercial partner companies and original- equipment manufacturers, said Eskom research, testing and development chief engineer for transformers Adesh Singh.