The next advancement in long-duration energy storage may not be about storing more electricity, but the role batteries could play in the future of power systems, including the potential of a Na-S battery.
This article features sodium-sulphur batteries and what their established applications and ongoing development could mean for the future of long-duration energy storage in large-scale power systems, particularly in relation to the efficiency of battery technology.
Growing electricity demand has placed increasing pressure on existing transmission and distribution networks, particularly during peak consumption periods.
According to the International Energy Agency’s (IEA) Electricity Mid-Year Update 2026, global electricity demand is projected to grow by 3.6% in 2026 and 3.8% in 2027. In Australia, the Australian Energy Market Operator’s (AEMO) 2026 Integrated System Plan projects that annual underlying electricity consumption across the National Electricity Market could nearly double from approximately 205 terawatt-hours (TWh) to 390 TWh by 2050.
This growing demand highlights the importance of using existing electricity infrastructure more efficiently.
Sodium-sulphur batteries could help manage peak electricity demand by storing energy during periods of lower consumption and supplying it when demand rises. Their multi-hour discharge capability makes them relevant to applications such as load levelling, which balances electricity demand over time, and peak shaving, which reduces the highest levels of demand on the network.
For long-duration energy storage, sodium-sulphur batteries could help electricity providers meet peak demand without immediately building new power lines or upgrading existing ones. For example, when electricity demand in an area exceeds what the existing network can comfortably handle, batteries installed near that area could supply stored electricity during peak periods. This would reduce the amount of electricity that needs to pass through already heavily loaded power lines. As a result, electricity providers could make better use of existing infrastructure and potentially delay costly network upgrades, particularly when high demand occurs for only a few hours at a time.
A battery’s rated storage capacity does not always reflect how much electricity it can deliver in practice. For long-duration energy storage, the amount of usable energy and the length of time it can be supplied are important considerations when evaluating system performance.
According to the National Renewable Energy Laboratory’s (NREL) 2021 USAID Grid-Scale Energy Storage Technologies Primer, sodium-sulphur batteries are among the technologies suited to applications requiring several hours of electricity storage. However, the amount of usable electricity they can deliver depends on factors such as discharge rate, battery temperature, energy consumed by heating systems, and conversion losses. For example, a sodium-sulphur battery rated at 1.45 megawatt-hours (MWh) does not necessarily deliver the full 1.45 MWh as usable electricity. Some energy may be consumed by heating and supporting equipment, while conversion losses and operating limits can further affect the amount available.
For long-duration energy storage, this means a battery with sufficient rated capacity may still fall short of meeting a facility’s electricity needs for the required duration. For instance, a facility needing a continuous electricity supply for six hours would benefit from knowing how much usable energy the complete battery system can deliver over that period, rather than relying on its rated capacity alone. This makes usable energy a more practical basis for selecting and comparing storage systems.
Conventional sodium-sulphur batteries often operate at approximately 300–350°C to keep their active materials molten. Maintaining these temperatures requires heaters, thermal insulation, and temperature monitoring systems, alongside protective measures to manage risks such as overheating and leakage of high-temperature reactive materials. These additional requirements increase the complexity of battery design and operation.
Research into room-temperature sodium-sulphur batteries could offer a way to reduce the thermal management requirements of conventional systems. A 2024 review on “A Critical Review on Room-Temperature Sodium Sulphur Batteries: From Research Advances to Practical Perspectives” examined advances in room-temperature sodium-sulphur battery technology, but challenges involved polysulphide migration, slow electrochemical reactions, and cycling stability that could limit its practical development.
For long-duration energy storage, successful room-temperature sodium-sulphur batteries could reduce the need for expensive heating equipment and regular maintenance of high-temperature systems. This could lower the cost and complexity of installing and operating these batteries, making them more practical for smaller commercial and industrial facilities that need to store electricity for several hours.
Instead of being more suitable for large-scale installations such as grid-connected storage facilities and industrial energy systems that can accommodate specialized heating systems, sodium-sulphur batteries could become an option for a wider range of energy storage projects, such as in commercial buildings, manufacturing facilities, and solar-powered industrial sites, where simpler heating requirements could reduce installation and maintenance costs.
As sodium-sulphur batteries continue to develop, evaluating their suitability for long-duration energy storage involves understanding more than battery capacity. Knowledge of power system performance, energy storage technologies, and electrical network integration can help engineering professionals assess where these systems could provide practical value.
The Engineering Institute of Technology (EIT) offers relevant learning pathways, including the Bachelor of Science (Electrical Engineering), Master of Engineering (Electrical Systems), and courses in Renewable Energy along with Professional Certificates of Competency. These cover areas relevant to electrical power systems, renewable energy integration, and engineering design to help learners develop the technical knowledge to evaluate storage performance and support the integration of emerging battery technologies.
Through these studies, engineering professionals can strengthen their ability to make informed decisions about energy storage solutions as electricity networks evolve.
References
Electricity Mid-Year Update 2026
Australia’s first grid-connected sodium sulphur battery goes online
This article was published November 12th, 2026 and the content is current as at the date of publication.
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