Energy Vault and Eskom Announce Strategic Development Agreement to Deploy Grid-Scale Gravity Energy Storage Systems in South Africa

Key Terms

gravity energy storage system technical

A gravity energy storage system stores electricity by using surplus power to lift a heavy weight or raise a mass, then converts the potential energy back into electricity when the weight is lowered—think of it as a giant mechanical battery similar to a pumped-storage dam but using solid weights or blocks. Investors care because it offers long-lived, low-maintenance capacity for smoothing renewable output, providing grid backup and trading opportunities, and can create steady revenue streams with predictable operating costs.

long duration energy storage technical

Long duration energy storage is a way to save large amounts of electricity for many hours, days, or even weeks and release it when the grid needs power, like a giant household battery or water tank for the electric system. It matters to investors because it helps make wind and solar more reliable, cuts the need for expensive backup plants, and creates steady income opportunities from selling stored energy, grid services, or capacity contracts, so it can materially change project economics and long‑term returns.

grid-scale technical

Grid-scale describes energy equipment or projects built large enough to directly serve the electrical power grid — for example big batteries, utility power plants, or large storage systems measured in megawatts or megawatt-hours. For investors it signals utility-grade size, different revenue streams and regulatory rules than small consumer products, and a role in keeping the grid stable and integrating renewables; think of it as the industrial water tank that smooths supply for a whole city rather than a home bucket.

utility-scale energy storage technical

Large, grid-connected systems that store energy — typically batteries, pumped hydro, or other technologies — so electricity can be held when supply exceeds demand and released when needed. Like a neighborhood-sized power bank for the electric grid, these projects help smooth out fluctuations from renewables, improve reliability, and avoid expensive peak-time generation; investors care because they can generate steady revenue from grid services, capacity payments and shifting energy to higher-priced periods.

AI compute infrastructure technical

AI compute infrastructure is the physical and software setup—specialized processors, servers, data storage, networks and cooling—that lets artificial intelligence models run at scale, like the engines, roads and fuel stations that let cars travel. For investors it matters because the quality and cost of this infrastructure determine how fast and cheaply a company can develop, deploy and monetize AI services, affecting capital spending, profit margins and competitive position.

material science technology technical

Material science technology is the study and development of new materials and the methods to make and use them, such as stronger alloys, lighter composites, or advanced coatings. For investors, it matters because better materials can enable cheaper manufacturing, longer-lasting products, or entirely new markets—think of it like upgrading the ingredients in a recipe to improve taste, cost, or shelf life, which can boost a company’s competitiveness and profit potential.

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Eskom and Energy Vault are announcing an agreement to deploy a gravity storage system at the Hendrina Power Station in Mpumalanga province, South Africa, with intention to license, co-develop and partner to deploy up to 4GWh of long duration energy storage across 16 SADC member states

The partnership will significantly advance regional efforts to transition away from coal, leverage joint material science technology for economic re-use of waste coal ash within the energy storage medium while enabling grid reliability, job creation, and local economic development

WESTLAKE VILLAGE, Calif. & JOHANNESBURG--(BUSINESS WIRE)-- Energy Vault Holdings, Inc. (NYSE: NRGV) (“Energy Vault” or “the Company”), a global leader in sustainable, grid-scale energy storage and AI compute infrastructure solutions, today announced a strategic development agreement with Eskom Holdings SOC Limited (“Eskom”), South Africa’s state-owned electricity utility, to deploy a long-duration gravity energy storage system (GESS).

The first GESS plant will be built at Eskom’s Hendrina Power Station in Mpumalanga, South Africa, one of the utility’s oldest operating stations. The system is expected to provide 25 MW of capacity with four hours of storage, equivalent to 100 MWh, and is designed to be fully scalable, up to 4GW. This landmark agreement establishes a partnership between the two companies, aligning their long‑term interests to accelerate the decarbonization of Southern Africa’s power sector.

Under the terms of the agreement, Energy Vault will provide Eskom with its latest EVx 2.0™ GESS technology system, and associated equipment, together with on‑site engineering, project management, and localized training support. The partnership intends to license, co‑develop, and collaborate on the deployment of up to 4 GWh of GESS storage, with significant potential across the 16-member Southern African Development Community (SADC) region by 2035.

Energy Vault’s EVx 2.0™ GESS platform incorporates significant advancements over the previous EVx design, particularly in the software orchestration, mechanical operation, energy efficiency, construction automation, and construction tooling. These enhancements enable a system capable of scaling to multi-gigawatts (GW’s) of efficient energy storage to support growing renewables penetration. The EVx 2.0 design also features improved material science technology for the economic re-use of ash from coal combustion as the storage medium in the blocks, which may weigh up to 25-30 tons each.

“This landmark agreement with Eskom represents a transformational milestone for Energy Vault and for Africa’s energy future,” said Robert Piconi, Chairman and Chief Executive Officer. “By combining our breakthrough EVx 2.0 platform with Eskom's extensive power generation, grid expertise and regional reach, we're not only advancing long-duration storage at unprecedented scale but also pioneering a new model for sustainable industrial development. This partnership will create local jobs, establish resilient supply chains, and demonstrate how gravity energy storage can accelerate Africa's transition from coal dependency to energy independence and security — all while delivering reliable, affordable power to communities that need it most."

This collaboration directly supports Eskom’s Just Energy Transition Partnership (JETP) initiative, which is focused on achieving a sustainable and equitable transition away from coal while ensuring grid reliability, job creation, and local economic development.

“Eskom is committed to reducing the environmental impact of its electricity generation activities and will continuously drive projects to support South Africa’s local and global emission reduction targets and transition responsibly. Eskom’s strategy is designed to position us as a resilient and competitive energy leader in a liberalised energy market. We will drive a just and inclusive energy transition that includes intensifying the repowering and repurposing of coal power stations and exploring clean coal technologies and solutions using technology as a strategic enabler to improve efficiencies and lower the cost of electricity. This partnership with Energy Vault and its innovative gravity storage technology will play a pivotal role in achieving our Just Energy Transition goals,” said Dan Marokane, Group Chief Executive, Eskom Holdings.

Southern Africa is undergoing a dynamic transformation in its energy landscape, with governments and utilities across the SADC region working to expand access to reliable, affordable, and sustainable electricity. Today, 56% of the SADC region’s population has access to electricity, up from just 36% a decade ago, reflecting the impact of coordinated regional efforts and investment in infrastructure. Coal remains the dominant source of power generation, contributing over 80% of South Africa’s electricity supply in 2024, but the region is actively diversifying its energy mix. Utility-scale energy storage technologies are set to play a key role in integrating renewables, strengthening national grid resilience, and improving grid reliability—while also unlocking new opportunities for industrial growth, job creation, and community development.

This agreement positions Eskom and Energy Vault as regional leaders in grid-scale, long-duration storage and underscores both parties’ commitment to driving a clean, just, and resilient energy transition for Southern Africa.

About Energy Vault

Energy Vault^® is an integrated power infrastructure platform that builds, owns and operates flexible, reliable energy systems to accelerate time-to-power for utilities, independent power producers, industrial customers and the AI and data center market. At the core of its platform is a technology-agnostic, software-enabled architecture that is designed to accelerate project delivery, optimize performance and drive faster time-to-revenue. Energy Vault’s integrated solutions combine energy storage, generation, and advanced energy management to deliver scalable infrastructure tailored to customer needs. Its portfolio spans short-, long-, and multi-day duration storage, enabling reliability, flexibility and cost efficiency across applications. For utilities and grid operators, Energy Vault provides firm, flexible capacity ​enhances grid stability and helps to ensure reliable power delivery. For industrial and data center customers, the platform enables resilient, cost-efficient power supply to support critical operations. Through its Build, Own & Operate model, Energy Vault generates long-term, recurring revenues while delivering project execution excellence across development, delivery and operations. By combining innovation with disciplined execution, Energy Vault is redefining how power infrastructure is developed and deployed – delivering reliability, flexibility and scale in a rapidly evolving global energy market. Please visit www.energyvault.com for additional information.

About Eskom Holdings SOC Ltd

Eskom Holdings SOC Ltd is a state-owned corporation (SOC) and South Africa’s primary electricity utility, entirely owned by the South African government. Eskom operates across the full electricity value chain—generation, transmission, and distribution—supplying over 86% of South Africa’s energy needs and approximately 20% of the electricity produced on the African continent. Governed by a dual mandate to ensure financial sustainability while driving socio-economic growth, Eskom is committed to a responsible transition toward a lower-carbon future. The entity maintains a vast national network of approximately 33,000km, balancing supply and demand in real-time to power the nation’s economy and participate in the Southern African Development Community (SADC) electricity market. Please visit Eskom Holdings SOC Ltd for more information.

Forward-Looking Statements

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Energy Vault Contacts:
Investors energyvaultIR@icrinc.com
Media media@energyvault.com

Eskom Media Contact:
Mediadesk@eskom.co.za

Source: Energy Vault Holdings, Inc.