Energy Vault and Eskom Advance Gravity Energy Storage Deployment in South Africa
Energy Vault Holdings, Inc. has entered into a strategic development agreement with Eskom Holdings SOC Limited to deploy long-duration gravity energy storage systems in South Africa, marking a significant step toward strengthening grid reliability and accelerating the region’s transition to cleaner energy sources. The partnership combines Energy Vault’s advanced gravity-based storage technology with Eskom’s extensive utility infrastructure and operational expertise to support decarbonization efforts across Southern Africa.
The collaboration will begin with the construction of the first Gravity Energy Storage System (GESS) plant at Eskom’s Hendrina Power Station in Mpumalanga, South Africa. Hendrina is one of Eskom’s oldest operating coal-fired power stations and has become a focal point for the utility’s efforts to repurpose aging infrastructure as part of its long-term energy transition strategy. The planned storage facility is expected to deliver 25 MW of power capacity with four hours of energy storage, equivalent to 100 MWh. Importantly, the project has been designed with scalability in mind, allowing future expansion toward multi-gigawatt-scale energy storage deployments.
The agreement establishes a long-term strategic relationship between the two organizations with ambitions extending far beyond a single pilot project. Under the terms of the partnership, Energy Vault will provide its latest EVx 2.0 gravity energy storage technology, including associated equipment, engineering services, project management support, and localized workforce training programs. The companies also intend to collaborate on licensing and co-development opportunities aimed at deploying up to 4 GWh of gravity storage capacity throughout Southern Africa by 2035.
Gravity energy storage systems represent an alternative to traditional battery-based storage technologies. Instead of relying on chemical reactions, the system stores energy by lifting heavy composite blocks when excess electricity is available and then releasing that stored potential energy to generate electricity when demand rises. This approach offers several advantages, including long operational life, reduced degradation over time, and the ability to use locally sourced materials in construction.
Energy Vault’s EVx 2.0 platform incorporates several technological improvements over earlier versions of the company’s gravity storage systems. These upgrades include advancements in software orchestration, automated construction systems, energy efficiency, and mechanical operations. The platform is specifically designed to support large-scale renewable integration by delivering flexible long-duration storage capable of balancing intermittent solar and wind generation.
One of the most notable innovations in the EVx 2.0 design is the use of recycled coal ash as part of the storage blocks used in the system. The blocks, which can weigh between 25 and 30 tons each, are produced using improved material science technologies that allow the reuse of coal combustion byproducts. This approach not only supports circular economy principles but also provides a practical pathway for repurposing waste materials from coal-fired power generation facilities.
For South Africa, where coal continues to dominate the energy mix, this aspect of the project carries significant symbolic and practical importance. Coal currently accounts for more than 80% of the country’s electricity generation, making the transition to cleaner energy particularly complex. The reuse of coal ash within renewable-supporting infrastructure demonstrates how existing industrial resources can be integrated into future energy systems while minimizing environmental impacts.
Robert Piconi, Chairman and Chief Executive Officer of Energy Vault, described the agreement as a major milestone for both the company and Africa’s broader energy transformation. According to Piconi, the partnership showcases how gravity-based energy storage can help countries transition away from coal dependency while improving energy security and affordability. He also emphasized the project’s potential to create local jobs, establish regional supply chains, and support sustainable industrial development.
The collaboration aligns closely with Eskom’s Just Energy Transition Partnership (JETP), a strategic initiative focused on enabling a fair and balanced transition away from coal-fired electricity generation. The JETP framework seeks to reduce carbon emissions while also protecting workers, supporting local communities, and maintaining grid reliability during the transition process.
Eskom Group Chief Executive Dan Marokane emphasized that the utility remains committed to reducing the environmental impact of its operations while ensuring reliable electricity supply. He noted that Eskom’s long-term strategy includes repowering and repurposing aging coal facilities, investing in cleaner technologies, and leveraging innovative solutions to improve operational efficiency and reduce electricity costs. Marokane highlighted gravity energy storage as an important enabling technology that can help Eskom achieve its transition objectives without compromising energy stability.
The partnership comes at a critical time for Southern Africa’s power sector. Across the 16-member Southern African Development Community (SADC) region, governments and utilities are working to improve access to electricity while also modernizing aging infrastructure. Electricity access across the region has risen substantially over the past decade, increasing from approximately 36% to around 56% of the population. Despite this progress, significant challenges remain, including supply shortages, aging generation assets, and increasing demand for electricity driven by economic growth and industrial development.
Renewable energy deployment is accelerating across Southern Africa, particularly in solar and wind generation. However, the expansion of renewable energy introduces new grid management challenges because renewable generation is intermittent and weather dependent. Long-duration energy storage systems are increasingly viewed as essential infrastructure for balancing electricity supply and demand, stabilizing grids, and maximizing renewable energy utilization.
Gravity storage systems could play an especially valuable role in regions where utilities seek alternatives to lithium-ion batteries for large-scale storage applications. Unlike conventional battery technologies, gravity-based systems do not rely heavily on imported critical minerals and may offer longer operational lifespans with lower degradation rates. In markets with abundant industrial materials and existing infrastructure, gravity storage can potentially provide cost-effective and sustainable long-duration storage solutions.
The Hendrina project may also serve as a model for future energy transition projects across Africa. Many countries on the continent continue to rely heavily on coal, oil, or gas-fired power generation while simultaneously seeking to expand renewable energy capacity. Repurposing legacy power plant sites into clean energy hubs with integrated storage infrastructure offers a pathway for maintaining economic activity and employment while reducing emissions.
The agreement between Energy Vault and Eskom also underscores growing international interest in Africa’s evolving energy sector. As utilities across the continent pursue modernization and decarbonization goals, partnerships involving advanced storage technologies are expected to become increasingly important. Long-duration storage is widely regarded as a key component of future power systems because it enables renewable energy to provide reliable electricity even during periods of low generation.
In addition to improving energy reliability, the partnership is expected to generate broader economic benefits. Localized training initiatives included in the agreement aim to support workforce development and technical skills transfer within South Africa. The project could also stimulate domestic manufacturing and supply chain opportunities linked to construction materials, engineering services, and energy infrastructure development.
By combining Eskom’s operational reach with Energy Vault’s gravity storage technology, the companies aim to position themselves as regional leaders in utility-scale long-duration energy storage. Their collaboration reflects a broader shift within the global energy industry toward integrating innovative storage solutions as countries pursue decarbonization targets and more resilient electricity systems.
As Southern Africa continues expanding renewable energy generation and modernizing its grid infrastructure, projects like the Hendrina gravity storage facility could become increasingly influential in shaping the region’s energy future. The partnership between Energy Vault and Eskom demonstrates how advanced storage technologies can support a cleaner, more flexible, and more reliable power system while also contributing to economic development and industrial transformation across the region.
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