With the exponential increase in renewable energy installed globally there has been a commensurate increase in demand for transmission. While the focus has been on transmission related to lines and substations in-country, there needs to be a greater focus on interconnectors.
Regional transmission interconnectors are infrastructure systems that link electricity grids across national or regional borders. Their primary purpose is to facilitate the efficient exchange and distribution of electricity between neighbouring regions, allowing countries to optimise the use of surplus energy rather than curtail it, diversify the energy mix and minimise energy losses.
These interconnectors enhance grid resilience, balance supply and demand and promote stability in power systems. Additionally, they foster cross-border co-operation in energy policies, contributing to sustainability goals and potentially lowering energy costs for consumers.
The value of regional transmission interconnectors becomes particularly evident when considering their role in managing energy generation and facilitating power exports. For instance, interconnectors within the Southern African Power Pool (SAPP) have enabled countries to export primarily excess energy, aiding in regional energy balance and economic co-operation. The Southern African Development Community, through SAPP, has an interconnected grid with trades that differ daily. The total traded monthly volumes between August 2024 and March 2025 varied between 30.7GWh and 119.8GWh owing to fluctuating regional output.
SA, a leading player in the SAPP, has been able to sell surplus energy to its neighbours during periods of low domestic demand, thus optimising the use of its energy resources by preventing curtailment.
Interconnectors also play a strategic role in enhancing grid resilience through blackstart capabilities — procedures used to restore power to a grid after a complete shutdown. The Iberian blackout provides a striking example where interconnectors proved invaluable. During the blackout interconnectors facilitated the rapid mobilisation of surplus energy from neighbouring countries, accelerating the recovery of the affected grid.
This demonstrated the critical importance of cross-border infrastructure in mitigating the effects of major disruptions. By creating pathways for shared electricity supply, interconnectors enhance a region's ability to respond efficiently to crises, bolstering overall energy security.
In the case of SA such interconnected networks allow for the seamless export of surplus solar energy generated during peak production, ensuring that renewable resources are not curtailed and allowing for the import of hydro and gas for the evening ramp-up period. Interconnectors thus emerge as an alternative solution for balancing regional energy demands, stabilising grids and fostering sustainable co-operation across borders, even amid the challenges posed by transmission infrastructure complexities.
Proposed new interconnectors such as Angola-Namibia, Botswana-SA, Mozambique-Zimbabwe-SA and Mozambique-Malawi would unlock economic growth through regional trade, but they are not without risks. One prominent concern is the potential for cross-border disputes or geopolitical tensions, as electricity flows may become a point of contention during times of conflict, supply shortages or price fluctuations.
In addition, the infrastructure for interconnectors can be costly and complex to implement, requiring substantial investment and co-ordination between multiple nations. These are some of the challenges that have beset the infamous Inga project in the Democratic Republic of Congo.
There is also the risk of over-reliance on interconnected grids, which could amplify the effect of system failures; a major outage in one region might cascade across borders, causing widespread disruptions. Cybersecurity threats further compound this issue, as interconnected systems are more vulnerable to sophisticated cyberattacks that could compromise critical operations.
Finally, navigating regulatory differences and aligning energy policies between countries pose challenges, potentially slowing progress and undermining efficiency in shared energy networks.
Interconnectors need vision, political fortitude and strategic implementation to facilitate regional trade and economic growth in Africa, transforming energy into shared prosperity amid diverse challenges and aspirations.
• Mashele, an energy economist, is a member of the board of the National Transmission Company of SA.
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