For South Africa’s leading businesses, building resilience into their energy supply has become essential. This is especially true for MTN, Africa’s largest telecoms provider, whose Johannesburg headquarters must operate reliably around the clock. Faced with growing grid instability, rising tariffs and ambitious sustainability goals, MTN needed a solution that would stabilise its energy supply and support long-term savings and emissions reductions.
A microgrid designed for reliability and speed
Terra Firma engineered and delivered a fully integrated 5 MWp solar plant with 6 MWh of battery storage, creating one of Africa’s largest on-site microgrids. The system combines four power sources: solar PV, battery storage, municipal grid supply and gas generators, and synchronises them through an intelligent central Energy Management System (EMS).
Despite the scale and complexity, the project moved from design to commissioning in under ten months, setting a strong benchmark for delivery on a site of this size and sensitivity.
Project snapshot
- Client: MTN
- Location: Johannesburg headquarters
- Solar PV Capacity: 5 MWp
- Battery Storage: 6 MWh (2 MVA)
- System: Grid-tied microgrid integrating solar, BESS, grid & gas generators
- Installation: Carport + ground-mount
- Delivery Time: <10 months
Impact
The microgrid now supplies 40% of MTN’s total energy needs, generating 8.7 GWh of clean energy annually and avoiding more than 9,000 tonnes of CO₂ emissions every year. With 9,000 solar panels deployed across carport and ground-mount structures, the system provides MTN with the assurance of stable, predictable and low-carbon energy even during periods of grid instability.
Most importantly, the project strengthens MTN’s operational resilience while advancing its sustainability commitments and reducing exposure to volatile electricity tariffs.
Why microgrids are becoming essential for large C&I users
Commercial and industrial sites often operate equipment and processes that are sensitive to power disturbances. Load shedding, voltage dips and grid variability can disrupt IT systems, affect cooling requirements and interrupt operations. This is especially true for businesses with 24-hour facilities, call centres, data infrastructure or critical service functions.
A microgrid helps stabilise these risks by combining different energy resources and managing them as a coordinated whole. Solar and battery storage reduce daytime grid dependence, while the EMS makes real-time decisions about the most reliable and cost-effective source at any moment. For a digital-first organisation like MTN, this level of control is crucial.
The project also reflects a growing trend across the C&I sector: large corporates are increasingly investing in behind-the-meter energy systems to reclaim control over operational continuity and long-term energy costs. As grid pressure grows and electricity prices rise, microgrids are becoming central to business strategy, not just sustainability.
Part of the 6 MWh battery storage system that supports MTN’s solar-plus-storage microgrid
Why battery storage makes a meaningful difference
Battery storage is central to how modern C&I microgrids perform. For organisations that depend on stable, uninterrupted power, it acts as a buffer against short outages, voltage dips and moments when the grid becomes unreliable. It also helps smooth out fluctuations in solar generation, which is important on sites with sensitive equipment or around-the-clock operations.
A well-designed BESS can support part of the site’s load during peak periods, reduce reliance on diesel generators and lower exposure to high time-of-use tariffs. It also enables smoother transitions between energy sources, which protects equipment and helps maintain consistent power quality. As more South African businesses look for ways to control long-term energy costs and reduce operational risk, battery storage is becoming a practical and essential component of on-site energy systems rather than an optional extra.
Engineering for a live operational environment
Projects of this size usually require careful sequencing, coordination and safety planning, especially when delivered on large campuses that remain active throughout construction. Typical considerations include managing traffic flows, scheduling work around high-use areas and ensuring that installation activities do not interrupt daily operations.
For ground-mounted or carport-style systems like this one, engineering teams often carry out geotechnical assessments, civil works and electrical routing studies to ensure long-term stability and safe integration. These steps are standard for commercial and industrial projects of this scale, even though the specifics vary from site to site.
Integrating a microgrid with an existing electrical network also tends to involve extensive testing and commissioning. This helps ensure smooth transitions between the different energy sources and supports overall system reliability.
A section of the solar carport system at MTN’s head office.
A strategic shift in MTN’s long-term energy plan
The microgrid forms part of MTN’s wider move towards becoming more energy independent. MTN has a longer-term strategy to be able to operate in island mode when necessary, reducing reliance on municipal supply during load shedding and lowering diesel generator usage.
This change is also linked to MTN’s net-zero emissions target for 2040. The solar-plus-storage system supports those goals by cutting emissions, lowering fuel consumption and providing a cleaner, more stable platform for future energy investments. It also reduces the environmental and financial costs linked to running large diesel generators, something that has affected all major telecoms providers during years of severe load shedding.
The business case for clean, reliable on-site power
Energy costs and grid instability have become major issues for South African corporates. Telecoms operators in particular have faced steep increases in energy spending due to backup generation requirements. The MTN microgrid helps address this challenge in several ways:
- it reduces daytime grid demand
- it limits diesel reliance
- it provides protection during grid failures
- it creates a predictable cost base for long-term planning
As more businesses look to model similar systems, the MTN project shows that large-scale on-site solar and battery storage can be deployed quickly and safely, even on complex and active campuses.
Raising the bar for on-site energy systems
By delivering one of the continent’s largest on-site solar-plus-storage microgrids in record time, Terra Firma has set a new standard for what’s possible in large-scale commercial and industrial energy solutions. The MTN project demonstrates how integrated engineering, precise execution and advanced energy management can deliver reliable, low-carbon energy for critical facilities.
