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4 October 2019

South Africa’s Eskom plans biggest battery site by 2021

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 boring countries. It has debt spiraling out of control and for the first time last year is profit did not cover its debt repayments. This is not a strong position from which to invest in renewables, but it may happen.

The plan is to build large-scale energy storage tender, the first of its kind in the country and in Africa as a whole, will be split into two phases, with an initial 200 megawatts/800 megawatt-hours of capacity to be built by December 2020, an Eskom official said to GreenTech Media.

The initial installation alone would make it the largest battery installation in the world. Currently that record is around 150 MW in China, and China is also working on a 200MW/800MWh Vanadium flow battery in Dalian, reported back in 2017 for peaking capacity, grid stability and black-start operations which should come online early in 2020 – so about the same size as the first phase of this one.

This first phase is split into four separate installations and then followed by 160 megawatts/640 megawatt-hours to be installed a year later. The news was picked up in a company webinar and has not been reinforced by a press release or financial announcement. However, the tender has been approved by the South African Ministry of Finance. The second phase will also include 60 MW of solar integrated with the battery storage, along with an asset performance management system.

Eskom is virtually a monopoly and supplies 90% of South Africa’s electricity, and owns 45 GW of generation. It has not been a player in renewables before, but borrowed some cash from the World Bank to build out a 100 MW concentrated power plant plus energy storage. This never came to fruition and the money has to be used on renewables somewhere, and it went back to an old plan that was filed back in 2017 to use distributed battery storage. Essentially then, these are multiple separate sites for smaller batteries, all under the control of the same orchestration system.

At this stage the precise technology that will be used is not known. We have some real doubts that it will ever happen. It is on the large side for a series of Lithium Ion installations, although that could be done as a series of smaller installations, and it is at the high end of feasibility for a series of Vanadium Flow batteries, but we have heard of similar projects around the world and as we say, this is really multiple localized installations – not one large one.

Eskom says it has developed its own system specification and has already handled site selection and has environmental approvals. Eskom also says that local supplies have to make up 20% of the energy storage plan, but that should not push it towards one storage technology or another. Specifically, the battery is to support renewable energy generation, smoothing out intermittent supply for multiple sites.