South African utility Eskom has asked the energy regulator to allow it to recover $1.6 billion in costs from 2013/14 when it ran expensive diesel plants and brought more green power to keep the lights on.
The regulator (NERSA) in Africa's most advanced economy in June rejected a request from cash-strapped Eskom to raise tariffs and the utility said it would seek alternative ways of funding.
Eskom's spokesman Khulu Phasiwe said the utility was over budget as it had to buy an extra 1,800 megawatts of green energy and used more diesel to run its expensive plants in 2013/14.
The regulator said it was assessing Eskom's request and did not say when it would publish its outcome.
"Should the results of the assessment indicate that Eskom has to reimburse the customers then the price of electricity would have to decrease. Similarly, if the customers have to reimburse Eskom the price would have to increase," National Energy Regulator spokesman Charles Hlebela said.
Eskom, which provides virtually all of South Africa's electricity, is scrambling to repair its ageing power plants and grid. Earlier this year, the utility was forced to impose almost daily power cuts that hurt economic growth.
Eskom said last week, however, that it does not expect to implement electricity blackouts until April 2016.