The union argues in court papers that the utility already has excess capacity and signing the deals would force coal-fired power plants to shut down, resulting in job losses.
"About 25% of the project equity is owned by foreign investors acting as a catalyst by providing investment and skills transfer to the establishment of the new green economy", he said.
In the ruling, the court says: "The respondents will have circumvented the process which is now pending before court; and the applicants will have no choice but to institute applications to review and set aside the awarding of the contracts".
"Numsa believes that the signing of these contracts would be detrimental for the working class of Mpumalanga and the country as a whole", the union said in an emailed statement, referring to a coal-rich province that has many power plants. "The energy minister was forced to give an undertaking in court that he would not sign the IPP agreements on Tuesday until the matter has been given a full hearing by the High Court".
After arguments were concluded, the court refused to grant an interim interdict against Eskom or the Minister but instead postponed the matter to 27 March 2018, with the responding parties to file their answering papers by 20 March 2018 and the applicants' parties to file their replying papers by 22 March 2018.
Government's long-awaited signing of agreements with 27 renewable energy independent power producer projects (IPPs) on Tuesday was blocked by an interdict that the National Union of Metalworkers of South Africa (Numsa) and Transform RSA obtained in the high court in Pretoria on Monday night.More news: Google Assistant Now Available on the iPad
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"The IPP roll out will raise the cost of electricity dramatically, because IPPs cost much more than coal-fired electricity". Extracting fossil fuels from underground is a "resource play".
"This is good news for several reasons", says Dr Dom Wills, CEO of solar project developer, SOLA Future Energy.
At a media briefing announcing the signing ceremony last week, Radebe said South Africa had reached a milestone following a protracted period of uncertainty.
She disputed Radebe's job-creation numbers, and said that the deal would only sustain the employment numbers claimed by the minister only in the construction phase of these renewable power stations.
"The usage of different types of energy supply‚ which includes renewable forms of power generation‚ is in line with the energy policy".
"What happened to the Eskom Build Programme?"