Introduction

Energy storage assets, particularly Battery Energy Storage Systems (BESS), are increasingly treated as important components of electricity-system reliability rather than merely as facilities that store and later discharge electricity. Their legal obligations arise from electricity legislation, grid-connection codes, system-operation rules, licence conditions, technical standards and contractual arrangements. In South Africa, the regulatory framework is principally linked to the Electricity Regulation Act 4 of 2006 (ERA), NERSA regulatory instruments and the South African Grid Code. NERSA's Battery Energy Storage Facilities Grid Connection Code establishes minimum technical and design requirements for storage facilities connected to transmission or distribution systems and requires specified categories of storage facilities to have the capability to provide ancillary services.

Meaning Of System Stability Obligations

System stability obligations require storage operators to operate their facilities in a manner that does not compromise the secure and reliable operation of the electricity network. Depending on the applicable connection category and contractual framework, obligations may include voltage support, frequency response, reactive-power control, balancing support, ramp-rate management, emergency response, controlled charging and discharging, and compliance with dispatch instructions.

The legal significance is that storage cannot always be treated as an ordinary commercial asset. When connected to the public grid, its operation may affect network frequency, voltage and system security. NERSA's BESS Grid Connection Code expressly states that it applies to battery storage facilities connected or seeking connection to the transmission or distribution system and is to be read with other applicable grid codes, rules and regulations.

Core Legal Obligations Of Storage Assets

A storage operator must generally comply with applicable connection requirements before operating its facility. These requirements may cover protection systems, control systems, communications, power-quality requirements, fault response, metering and operational performance.

A second obligation concerns ancillary services. Under the South African BESS Grid Connection Code, specified categories of BESS must have the capability to provide ancillary services in accordance with the System Operation Code. This demonstrates the transition from treating storage simply as an energy resource toward recognising it as a system-support resource.

A third obligation is compliance with system-operator instructions. Where a storage facility participates in dispatch, balancing or ancillary-service arrangements, contractual and regulatory rules may require it to respond within specified technical parameters. Failure to respond can create regulatory, contractual or potentially licensing consequences.

Voltage, Frequency And Emergency Stability

Storage can contribute to system stability by rapidly changing its power output. During periods of system stress, batteries may discharge to support supply or modify charging behaviour to reduce system demand. NERSA materials concerning battery storage recognise voltage regulation and ancillary-service functions as important network benefits.

The legal framework therefore increasingly connects technical capability with regulatory responsibility. A storage asset that represents itself as providing a particular grid-support function may be required to maintain the relevant capability and comply with performance standards.

Relevant Case Laws

Eskom Holdings SOC Ltd and Another v Sonae Arauco (Pty) Ltd [2024] ZASCA 177 is particularly relevant to the principle that electricity-system security can require operational intervention. The Supreme Court of Appeal confirmed that the South African Grid Code forms part of the regulatory framework applicable to licensees and that the system operator has duties to take prompt remedial action where an abnormal condition threatens reliable grid operation.

In Eskom Holdings SOC Ltd v Vaal River Development Association [2022] ZACC 44, the Constitutional Court examined the statutory and licensing framework governing electricity generation, transmission and distribution. The Court recognised the extensive regulatory powers of NERSA, including the ability to impose licence conditions concerning performance, service quality and electricity-system obligations.

In United Democratic Movement and Others v Eskom Holdings SOC Ltd [2023] ZAGPPHC 1423, the High Court considered the relationship between Eskom's licence obligations and the Grid Code. The judgment illustrates how technical grid-security requirements can acquire legal force through legislation and licensing arrangements.

More specifically concerning modern storage-connected projects, Sibanye Gold (Pty) Ltd and Others v Eskom Holdings SOC Ltd and Others [2026] ZAGPJHC 123 considered regulatory issues surrounding private generation facilities with or without energy storage. The judgment records the regulatory framework under which certain qualifying facilities may be exempt from licensing while remaining subject to applicable codes and registration requirements.

Regulatory Compliance And Enforcement

Storage operators must therefore distinguish between licensing status and technical compliance. A facility may fall within an exemption from a generation licence requirement while still being required to comply with grid codes, registration conditions and connection requirements. The Sibanye litigation demonstrates the practical importance of this distinction.

Non-compliance may lead to technical restrictions, contractual remedies, regulatory intervention, enforcement proceedings or changes to connection arrangements. The precise consequence depends on the applicable licence, code, connection agreement and regulatory instrument.

Conclusion

System stability obligations for storage assets represent an important development in modern electricity law. BESS facilities are increasingly regulated not merely according to the electricity they store or discharge, but according to their effect on system security and their capacity to provide network-support services. In South Africa, the NERSA BESS Grid Connection Code, the Electricity Regulation Act, the South African Grid Code and relevant licence and connection conditions create a framework requiring appropriate technical performance and system cooperation. The cases concerning Eskom, NERSA and grid stability demonstrate that reliability obligations can have enforceable legal consequences. As storage penetration increases, these obligations are likely to become increasingly important in regulating frequency response, voltage support, emergency operation, dispatch compliance and the broader resilience of the electricity system.