South Africa’s energy utility Eskom is preparing to launch a tender for 1.4 GWh of battery storage, likely to be the largest battery in the world once it gets built. The aim is to use it to support renewables on the grid, and to install it by December 2021. This is one of those “dramatic” moments when an operator that has been ignoring renewable energy finally realizes that it can be cheap, and cut its costs. Eskom has drifted into major losses over the past two years, and is looking for a new way forward. It has regulated control of revenues but has sold less electricity this year, seen a downturn in coal mining operations, and less sales to neigh…