The National Energy Regulator of SA (Nersa) has awarded Eskom only half of the money the utility asked for in its latest tariff application, and signalled that it could make further cuts if it found that governance failures at Eskom had inflated its costs.

The regulator’s decision, on Eskom’s regulatory clearing account (RCA) application, will add to whatever tariff increases Eskom is allowed from April 2019, but Nersa will decide only in September on how the extra tariffs will be phased in.

Nersa’s decision came as workers staging violent protests against cash-strapped Eskom’s 0% wage offer disrupted operations at several power stations.

This prompted the utility to implement load shedding during the Thursday evening peak.

Its decision also came after Eskom conceded during public hearings in May that alleged corruption and fraud at the utility could have affected costs, particularly its coal costs.

Nersa chairman Jacob Modise said on Thursday it "may initiate its own investigation into the governance failures in Eskom and may effect adjustments to Eskom’s revenue based on the relevant outcome of its investigation".

It could also adjust revenue in the light of findings by other bodies such as the Hawks, Special Investigating Unit, the Treasury, Parliament and any commission of inquiry. State capture at Eskom is the subject of several inquiries and is expected to feature prominently in the Zondo commission of inquiry into state capture, which starts its public hearings in August.

Eskom had asked for almost R67bn to compensate it for lower than expected electricity sales and higher than expected coal costs in the three years from 2014 to 2017, but Nersa on Thursday awarded it R32.7bn.

Nersa has become increasingly intolerant of Eskom’s constant pleas for more money to cover cost overruns, and in 2017 cut the 19.9% increase the utility asked for the current (2018-19) year to 5.2%, prompting Eskom to take it to court.

Eskom will apply to Nersa in August for the next three years of tariff increases. It is also likely to put in another RCA application in August, covering 2017-18.

Nersa is expected to wait for all these applications to determine what the total of Eskom’s application to cover its costs over the medium term is, so that it can have a full picture of what the overall effect will be and what the economy can afford.

Eskom acting chief financial officer Calib Cassim said on Thursday the utility would be able to fully understand the basis of Nersa’s decision once it had seen detailed reasons, which Nersa has not yet released.

Minerals Council SA economist Henk Langenhoven welcomed Nersa’s decision but said after several years of increases of 6% to 8%, the industry would be "on the floor" if there were further above-inflation tariff increases.

RMB credit analyst Elena Ilkova said Nersa "told us how much Eskom will be allowed to recover, but they didn’t tell us how it will be recovered or over what time period".

Ratings agencies are expected to update their ratings only after Eskom publishes its results in mid-July.