State-owned electricity utility Eskom argued on Thursday that it required additional revenue of R23-billion for the upcoming financial year to remain a going concern and told the National Energy Regulator of South Africa (Nersa) that further tariff increases, beyond the 5.22% already approved for next year, were required to enable it to migrate to financial sustainability.   Nersa is currently hosting public hearings as part of its deliberations on how to implement a regulatory clearing account (RCA) balance that had already been approved, as well as how it should respond to supplementary applications by Eskom arising from two recent adverse court rulings.