Battery Energy Storage Systems (BESS) can fast become the backbone of renewable microgrids in rural Africa. These systems balance supply and demand, improve power quality, and extend the operational hours of off-grid infrastructure. Hence, delivering reliable electricity to underserved communities and supporting rural businesses. But with rising demand comes growing complexity. How can we ensure that battery systems are not just deployed but designed and managed for long-term sustainability?
This was the central question of the RePower webinar, “Optimise Battery Design & Operations in Renewable Microgrids in Rural Africa”, held on 21 May 2025. The session brought together voices from both research and industry, featuring expert insights from Dr Zahra Esfahani, postdoctoral fellow at Aarhus University, and Carl Kies, Chief Engineer at BlueNova, one of South Africa’s leading battery manufacturers., one of South Africa’s leading battery manufacturers.
Together, they painted a detailed picture of the technical and economic realities of battery deployment in off-grid contexts and shared proven strategies to optimise system design, commissioning, and long-term operation.
A Researcher’s View: Smarter Systems for Rural Microgrids
Dr Zahra Esfahani opened the discussion by highlighting the rapid growth and need of battery storage across Africa. “Storage is no longer a backup but a backbone,” comments Dr. Esfahani. Installed capacity has risen dramatically, from just 31 MWh in 2017 to a projected 1,600 MWh in 2024. A clear indicator that energy storage is central to the continent’s energy transition. But growth alone is not enough, she warned. The real challenge lies in building battery systems that are technically robust, economically viable, and environmentally sustainable.
In rural microgrids, BESS perform four key functions: storing daytime power for use at night, reducing diesel generator use in hybrid systems, supporting voltage and frequency, and enabling higher solar penetration by minimising energy curtailment. Yet these benefits are only realised when the technology is chosen and operated with careful alignment to local needs.
“Successful battery deployment begins with careful selection,” Esfahani explained. “You need to tailor battery systems to the specific conditions of each site—load patterns, ambient temperatures, economic constraints, and even cultural usage habits.”
She outlined three critical factors in battery selection:
- Technical suitability, including compatibility of C-rate with dynamic loads, thermal resilience in temperatures exceeding 45°C, and alignment of depth of discharge with daily usage cycles.
- Economic feasibility, analysed through metrics such as levelised cost of energy (LCOE), battery replacement timelines, and logistics.
- Environmental sustainability, taking into account lifecycle emissions, materials sourcing, and recyclability.
Esfahani also presented comparative data across battery chemistries, highlighting how design must factor in specific site needs rather than defaulting to the cheapest or most common option.
Smart Operation: The Other Half of the Story
“Selection is only half the story,” she cautioned. Once deployed, operational strategies are crucial to extending battery life and maintaining system efficiency. Key practices include:
- Avoiding full charge/discharge cycles unless essential
- Dynamically managing depth of discharge according to load profiles
- Applying thermal derating to handle ambient heat
- Ensuring proper ventilation or insulation
- Take care of EMS and BMS data for adaptive scheduling, maintenance, forecasting, and degradation tracking
She highlighted the use of state-of-health modelling and aging simulation to predict battery degradation, allowing operators to act proactively. This data-centric approach is key to reducing system failures and ensuring performance aligns with design expectations.
Digital Twins and the Role of Modelling
One of the most powerful tools in optimising BESS is modelling before deployment. Esfahani advocated for the use of hardware-in-the-loop (HIL) setups to simulate system behaviour in realistic conditions.
“Even before physical deployment, modelling supports virtual validation,” she explained. These simulations help test how systems respond to scenarios such as overvoltage, overcurrent, and thermal stress. They also allow engineers to optimise EMS logic under variable solar generation and stochastic load patterns, common in rural contexts.
Batteries as the Weakest Link
A striking point raised was that in microgrids, batteries are typically the weakest link in terms of lifecycle durability and cost. “You must model the battery as a constraint, not just a component,” she argued. By doing so, designers can reduce overuse and extend operational years, effectively spreading capital costs over a longer timeline.
This framing forces engineers to design the entire microgrid system with the battery’s limitations in mind, resulting in smarter sizing, better thermal management, and longer-lasting deployments.
End-of-Life Planning: Think Ahead
Esfahani concluded with a reminder that every battery deployed today must be planned with its end of life in mind. “You need to think about the last day from the first day,” she said.
This includes estimating degradation rates, forecasting second-life potential, planning replacement schedules, and ultimately, managing recycling or disposal. She provided detailed tables showing how different use cases and load cycles lead to varied ageing trajectories, reinforcing the need for a holistic lifecycle strategy.
A Field Engineer’s Reality: Battery Systems at the Heart of Rural Electrification
Carl Kies, Chief Technology Officer at BlueNova Energy, focused his presentation on hands-on implementation, highlighting the challenges and opportunities of real-world battery deployments in rural Africa. At the core of Kies’ message was a stark reality: nearly half a billion people in sub-Saharan Africa still live without access to electricity. In response, initiatives like the World Bank’s Mission 300 aim to connect 300 million people to electricity by 2030. But, as Kies pointed out, “You do not build new power plants overnight.” Decentralised renewable energy systems, paired with effective battery storage offer a viable way forward in the short-to-medium term.
Drawing on examples from the field such as deploying battery units to remote islands off Mozambique, Kies highlighted the technical and logistical complexity of rural microgrids. These are not just simple systems, he stressed, but “mini power stations” that must deliver reliable, stable, and scalable energy in some of the world’s most challenging environments.
From navigating the corrosive effects of coastal humidity, to planning for unexpected shifts in community energy demand, Kies made it clear: effective battery design and operation is not just a technical requirement, it’s crucial for rural development.
The Role of Battery and Energy Management Systems in Microgrid Optimisation
Having touched on the importance of battery management systems (BMS), Kies delved into a concise explanation of what these systems do and why they are indispensable in off-grid renewable energy projects.
From a project financing perspective, a robust BMS is equally important. It extends the usable lifecycle of batteries (up to 40% longer in some cases) and underpins warranties that are crucial to securing investment. Furthermore, the high-resolution operational data it provides feeds directly into the energy management system (EMS), enabling optimised dispatch and system-level reporting.
Active vs Passive Cell Balancing
Kies explained the significance of active balancing over the more rudimentary passive method. In a simplified example, a battery with three cells at 80%, 50%, and 40% capacity respectively would be limited by the lowest-performing cell. Passive balancing simply bleeds off excess energy from higher-charged cells, essentially wasting potential capacity. Active balancing, by contrast, redistributes energy among the cells, making use of the average capacity across the pack. This not only improves energy efficiency but also enhances return on investment by ensuring greater yield from the battery system.
The EMS: The Brain Behind the Grid
Transitioning from the BMS, Kies introduced the energy management system (EMS), which he described as the “brain” of a microgrid. It enables comprehensive monitoring and control across all system components, from generation and storage to load management. Far more than just a software layer, the EMS offers what Kies calls a “power station dashboard”, a central control room for even the most remote and complex installations.
Operational Efficiency and Longevity
Pairing an advanced BMS with an intelligent EMS unlocks operational strategies that go well beyond standard performance. Charge and discharge cycles can be intelligently timed based on weather forecasts and load projections. Losses are reduced through optimised power flow, and round-trip efficiency (the ratio of energy retrieved to energy stored) that can be dramatically improved. Kies offered a striking comparison: systems operating at 60% round-trip efficiency yield only 6 kWh from every 10 kWh stored, while those reaching 98% efficiency return nearly the entire input at 9.8 kWh. This dramatic increase in usable energy directly translates to lower costs and greater reliability.
Thermal management is another critical factor. For lithium iron phosphate (LFP) batteries, optimal cell temperature is around 26°C. Maintaining uniform temperatures and voltages across cells ensures that the system ages uniformly, avoiding the early failure of any one component. Preventing deep discharges and overcharges, especially vital for older technologies like lead-acid batteries also preserves the system’s lifespan.
Data-Driven Risk Avoidance and Remote Monitoring
A key strength of the EMS lies in its use of data analytics for preventative maintenance. By continuously monitoring battery performance, the system can flag anomalies such as an underperforming cell before they become catastrophic. This allows for early intervention and avoids costly downtime or replacements.
One transformative advancement highlighted by Kies is the ability to conduct remote monitoring and control, even in the most isolated areas. Some technologies can enable real-time oversight and expert intervention from anywhere in the world. As Kies noted, this not only makes 24/7 monitoring viable but can also be coupled with community internet access. Hence, offering a broader socio-economic benefit.
Unified System Management and Long-Term Support
The EMS doesn’t just monitor batteries, it provides a unified platform for managing all grid components. In doing so, it ensures smooth, stable delivery of power, particularly important for productive uses in rural areas such as agriculture, education, and small enterprises.
Concluding his presentation, Kies summarised the key takeaways: batteries are essential for stable microgrids; BMS and EMS technologies are crucial to system efficiency and longevity; and the right technology partnerships are key to overcoming the unique challenges in rural African contexts. The careful selection of suppliers and integration partners can make or break a project.
A Look at Successful Deployments
Blue Nova’s track record supports the case. Their systems are operational across over ten African countries, with installations ranging from game lodges and rural communities to large commercial centres. One South African microgrid, for instance, integrates six 1 MW / 2.5 MWh battery units, capable of supporting over 6,000 households, either grid-tied or in full off-grid mode.
Current projects include deployments in Mozambique, where systems power remote villages, and collaborations with Africa GreenTec in Germany, which will test Blue Nova’s battery systems before scaling deployment across the continent.
The Road Ahead: Storage as an Enabler of Rural Transformation
As the webinar concluded, one message stood out: batteries are not silver bullets—but when designed and operated intelligently, they are powerful enablers of rural development.
Both Esfahani and Kies agreed that future success will require collaborative innovation. Researchers, developers, manufacturers, and policymakers must work together to refine battery technologies, develop adaptive control systems, and shape supportive market structures.
For communities across rural Africa, the implications are profound. More reliable power means better lighting, more productive businesses, enhanced education, and improved healthcare. As the energy transition accelerates, BESS will continue to play a pivotal role in unlocking these benefits.
Yet technology alone is not enough. As Esfahani reminded the audience, “We must approach battery storage as part of a larger system. It’s not just about installing equipment, it’s about understanding context, predicting behaviour, and managing performance over time.”
Kies echoed this sentiment from an industry standpoint: “We know the challenges. But we also know the solutions: smarter design, better modelling, and the right policies can make a huge difference.”
The RePower webinar offered a timely reminder: with the right tools and knowledge, BESS can do more than store energy—they can power lasting change.
Disclaimer: The RePower project is funded by the European Union under grant number 101096250. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or CINEA. Neither the European Union nor the granting authority can be held responsible for them.
