South Africa’s Eskom Resorts to Grid-Scale Gravity Energy Storage

Why It Matters

The partnership introduces a low‑carbon, long‑duration storage option that could help stabilize South Africa’s grid as it phases out coal, while offering a scalable model for the broader SADC region.

Key Takeaways

• Eskom signs agreement for 25 MW/100 MWh gravity storage at Hendrina.
• Energy Vault’s EVx 2.0 uses recycled coal‑ash blocks up to 30 tons.
• Framework allows up to 4 GWh storage across 16 SADC nations.
• Project targets long‑duration storage to support South Africa’s aging coal fleet.
• No timeline or financing details disclosed publicly.

Pulse Analysis

South Africa’s power landscape is at a crossroads, with Eskom grappling to keep a reliable grid while retiring coal‑fired capacity. The country’s electricity shortfalls have sparked interest in alternatives that can deliver hours‑to‑days of discharge, a niche where traditional lithium‑ion batteries fall short. Gravity‑based storage, which lifts heavy masses and releases them to generate power, offers a mechanically simple, potentially cheaper solution for long‑duration needs, positioning it as a strategic complement to renewable generation.

Energy Vault’s EVx 2.0 system distinguishes itself by repurposing waste coal ash into massive concrete blocks, each weighing 25‑30 tons. This circular‑economy approach not only reduces landfill pressure but also cuts material costs compared with purpose‑built steel or concrete modules. Advanced software orchestrates the lift‑and‑drop cycles, while automated construction shortens deployment timelines. Compared with pumped‑hydro, gravity storage requires far less site‑specific water resources, making it attractive for arid regions like Mpumalanga where the Hendrina plant sits.

The broader SADC framework outlined in the agreement could accelerate storage roll‑outs across 16 nations, fostering regional grid resilience and cross‑border power trade. If the pilot proves technically and economically viable, it may unlock financing pathways for similar projects, especially in markets where sovereign support is limited. However, the absence of disclosed financing and a clear schedule introduces uncertainty. Stakeholders will watch closely for performance data, as successful demonstration could reshape the continent’s approach to long‑duration energy storage and decarbonisation.