The wrong version of the state's long-awaited energy master plan was published in the government gazette on Friday morning, according to a report in Business Day.

The Integrated Resource Plan 2019 is the state's official blueprint for future energy generation, including things like projected electricity demand, cost estimates, and from what sources power will be generated.

But according to Business Day, the wrong version was published.

The department of energy's head of communications, Thandiwe Maimane, told Fin24 on Friday she was not aware that the wrong version was gazetted. She said she would have to confirm with her colleagues.

She did confirm, however, that a version of the plan emailed to media houses and journalists on Friday afternoon was the final and correct version. This version does differ in some respects from the gazetted version. The department on energy has not yet publicly said that the gazetted version is incorrect.

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The version of the IRP that was gazetted states that government will

"immediately commence the nuclear build programme to the extent of 2 500MW because it is a no-regret option in the long term and in case the Inga project does not materialise."

In the version emailed to journalists, the text states that government will

"commence preparations for a nuclear build programme to the extent of 2 500 MW at a pace and scale that the country can afford because it is a no-regret option in the long term."

This echoes statements made by Mineral and Energy Resources Minister Gwede Mantashe, at a briefing on the plan on Friday morning.

"We are talking of acquiring nuclear at a pace and cost country can afford. The IRP was approved [by Cabinet] on Wednesday, we are gazetting it today. Only now are we going to start doing practical work on the provisions of the IRP," he said.

Energy expert Chris Yelland tweeted on Friday afternoon that the wrong version had been gazetted.

Peter Attard Montalto, head of capital markets research at Intellidex, said in a note to clients on Friday that the wrong version had been sent out with changes affecting references to nuclear.

"There is confusion in the nuclear policy, with the 'wrong' version of IRP being gazetted with changes to the 'real' version especially in nuclear wording," he said.

"The final wording is this: 'commence preparations for a nuclear build programme to the extent of 2500 MW at a pace and scale that the country can afford because it is a no-regret option in the long term.' This is clearly designed to push forwards with planning and studies whilst still giving a get out of jail free card not to start actual build. What the paper does advocate is more research into small modular reactors to deploy. Overall we still see no chance of nuclear occurring though there is a question of how much money can be wasted investigating it."

The final version also does not refer to the fact that nuclear is necessary in case the Inga project may not materialise.

This project on the Congo River has been under construction for more than 10 years, and the IRP2019 notes that the DRC has not yet concluded the work needed for South Africa to start receiving electricity, as agreed, from 2023.

Yelland told Fin24 that the main table, with the projections for SA's energy needs, remained the same in the two versions, but that there were text changes.