The R745-million Kusile fraud and corruption case has been postponed to June.
Two former Eskom executives are among those charged along with several companies who unduly benefited from various contracts.
Investigations began when suspicions were raised about the construction of two large projects at the Medupi and Kusile power stations.
Former Eskom Chief Executive Officer Abram Masango, Contracts Manager France Hlakudi, businessman Maphoko Kgoemoeswana and Tubular Construction CEO Antonio Trindade appeared briefly in the specialised commercial crimes court.
They have been charged with fraud, corruption, money laundering, offering and receiving unauthorised gratification between 2014 and 2017.
The Hawks arrested the men in Gauteng, Limpopo and Mpumalanga back in December 2019.