Eskom has signed a landmark strategic development agreement with US-based Energy Vault Holdings, Inc. (NYSE: NRGV) to deploy a gravity energy storage system (GESS) at one of Mpumalanga’s oldest power stations — a move that could fundamentally reshape how South Africa stores and manages electricity. The deal marks one of the most significant energy storage announcements in the country’s recent history, and signals a serious shift in how Eskom intends to manage its long-term transition away from coal.
The first plant under this agreement will be constructed at Eskom’s Hendrina Power Station in Mpumalanga, a facility that has long been synonymous with the country’s coal-heavy past. The initial system is designed to deliver 25 MW of capacity with four hours of storage — totalling 100 MWh — but the real headline is the scalability built into the design. The partnership has ambitions to licence, co-develop, and deploy up to 4 GWh of GESS storage across the Southern African Development Community (SADC) region by 2035.
At the heart of the deal is Energy Vault’s latest EVx 2.0™ technology platform, which represents a meaningful upgrade over the company’s previous generation. The new system features improved software orchestration, enhanced mechanical efficiency, and smarter construction automation. Critically, it also incorporates advances in material science that allow for the economic reuse of coal combustion ash as the storage medium — a particularly relevant feature for a country sitting on decades’ worth of coal ash deposits.
Each storage block in the EVx 2.0 system can weigh between 25 and 30 tonnes, and the platform is designed to scale to multi-gigawatt capacity to support growing renewable energy penetration on the national grid. Energy Vault will provide Eskom with the technology, equipment, on-site engineering, project management support, and localised training as part of the agreement’s terms.
Eskom’s Gravity Energy Storage Deal Puts South Africa at the Frontier of Long-Duration Power Solutions
Eskom Group Chief Executive Dan Marokane was direct about the utility’s intentions, saying the partnership with Energy Vault and its gravity storage technology would play a pivotal role in the utility’s Just Energy Transition goals. Marokane emphasised that Eskom’s strategy includes the repowering and repurposing of coal stations, and that technology would serve as a key enabler in lowering the cost of electricity while reducing the environmental footprint of generation. This isn’t just rhetoric — the Hendrina site itself is proof of that intent.
Robert Piconi, Chairman and CEO of Energy Vault, described the agreement as a transformational milestone, not just for his company, but for Africa’s energy future more broadly. He pointed to local job creation, resilient supply chains, and the potential to demonstrate how gravity storage can accelerate Africa’s shift from coal dependency to genuine energy independence. These are bold claims, but the scale of the ambition behind the deal lends them some credibility.
The agreement also directly supports Eskom’s Just Energy Transition Partnership (JETP) framework, which seeks an equitable and sustainable move away from coal while protecting employment and stimulating local economic development. South Africa has faced enormous pressure — both domestically and from international partners — to manage this transition responsibly, and deals like this one are central to that effort.
The broader regional context is equally compelling. Across the 16-member SADC region, electricity access has grown from 36% to 56% of the population over the past decade — a significant achievement, but one that underscores how much work remains. Coal still accounts for more than 80% of South Africa’s electricity supply, and long-duration storage technology is widely regarded as a critical tool for integrating renewables without compromising grid stability.
What makes this agreement particularly noteworthy is that it isn’t simply a technology purchase — it’s a co-development partnership with regional licensing potential. If the Hendrina pilot performs as expected, the pathway to deploying gigawatt-scale gravity storage across Southern Africa becomes far more tangible. For a region grappling with chronic energy insecurity and the urgent demands of economic development, that prospect carries real weight. South Africa has been at the centre of the continent’s energy transition conversation for years — and with this deal, Eskom has moved from conversation to construction.