Eskom is installing a flagship 360MW battery energy storage system at 90 sites in the Western Cape, Northern Cape, Eastern Cape, and KwaZulu-Natal.
This 360MW/1440MWh flagship battery energy storage systems (BESS) project was first announced by Eskom in October 2018.
Eskom said at the time that the distributed battery storage infrastructure would be installed in containers at its sub-stations, including sub-stations located at renewable energy plants.
The battery storage system will allow increased energy storage capacity from future wind and solar-powered projects.
Eskom said the battery storage system will assist in its plan to increase solar and wind power in its energy mix from the current 7.2% (installed) to 25.6% in 2030 – a 350% increase.
The battery system will also be used to assist peak shaving, frequency support, and ancillary services in the distribution network.
How the project is funded
The battery energy storage project is funded by the African Development Bank and the World Bank, and is essentially a replacement for a planned concentrated solar power plant.
As part of its funding application for Medupi and Kusile, Eskom committed to building clean energy power plants.
One of these commitments included a 100MW concentrated solar power (CSP) plant which did not materialise.
Prince Moyo, Eskom’s general manager for power delivery engineering, explained that it was decided that a battery storage system with some solar power makes more sense.
“The size of the battery system would be similar to the energy the CSP would have generated, which is 1440MWh per day,” he said.
Eskom said it does not know how much the project will cost, but that it is expected to be in line with the “published cost/MW or cost/MWh”.
Eskom told MyBroadband that there is not an update on the project, but said the first phase is expected to be completed at the end of 2020, and the second phase at the end of 2021.
It added that the battery storage installations across the country will assist the company in various ways, which include:
- PV smoothing, where solar energy is stored during the day for despatch at peak times – typically at night.
- Wind energy firming, where battery storage is used to complement variable wind generation.
- Energy arbitrage, where energy is stored during low generation cost and tariff periods for despatch at high generation cost and tariff periods.
- Frequency and Voltage support, where battery capacity can be used in power mode as a generator when needed.
- Peak clipping, where the discharge of energy during peak times can be used to save costs.
Moyo said the battery energy storage system has clear business value for Eskom at a local and network level.