The Diagnostic We Already Have

Germany and Great Britain both had a difficult stretch this summer. On 23 June, grid frequency in Great Britain fell below the safe operating limit for a sustained period during the evening peak, with no market warning issued, and the system operator curtailed exports to the Netherlands and France to bring it back under control [15]. On 24 and 26 June, it issued electricity margin notices it had never issued in summer before [15]. Then, on 2 July, at a security-of-supply conference in Berlin, the head of Amprion, one of Germany’s four transmission system operators, said the country can no longer guarantee supply security into the early 2030s unless coal retirements are paused [13].

The author has argued for some time that South Africa’s energy transition carries a version of the same risk, only sharper. What Germany and Britain are now living through is not a distraction from that argument. It is the argument playing out in real time in two of the richest and most technologically sophisticated electricity systems on earth. If they can find themselves here, with all their institutional capacity, then a country retiring 9.5 gigawatts of baseload coal inside a 24-month window has every reason to take its own numbers seriously [4].

This is not a call to despair. It is the opposite. The reason South Africa’s position remains governable, in the author’s view, is precisely because the shape of the problem can be seen before it is hit. Germany and Britain are diagnosing their cases after symptoms appear. South Africa still has the chance to diagnose its own before it does.

A warning from the operator, not the opposition

The Amprion warning deserves to be read carefully, because of who made it. Christoph Müller is not a critic of the German energy transition. He runs one of the country’s four transmission system operators. Speaking in Berlin, Muller said no further hard coal plants should close until new capacity, principally the gas plants Germany plans to auction from September 2026, is actually running [13].

The numbers he cited are stark. Germany’s emergency reserve fleet totals 8.8 gigawatts, three-quarters of which is coal. Government projections put the possible shortfall during high demand periods at between 10 and 24 gigawatts by the end of the decade. Even the existing reserve would cover less than a third of the worst-case gap, and it shrinks further with every plant that closes [13].

Amprion’s own published commentary makes the structural point plainly. Renewables already supply more than half of German consumption, which is real progress, but it lengthens the stretches when the country needs something else to lean on, and storage is not yet able to close that gap on its own. The company’s assessment is that Germany will need meaningful new plant capacity by 2035, regardless of how quickly batteries are deployed [14].

Britain is not warning years ahead. It is already paying for the mismatch.

Britain’s problem runs in the opposite direction, but it comes from the same root cause: a mismatch between the speed of change and the system’s ability to absorb it. Since 20 May, the operator has also been trading under a market notice restricting its ability to reverse power flows across interconnectors with France, Denmark, the Netherlands and Belgium [2]. The B6 boundary, the transmission corridor connecting Scottish generation to English demand centres, has a boundary capability of 6.7 gigawatts [12], well below the wind generation capacity now sitting north of it. When the wind blows hard, the surplus is curtailed, and gas is dispatched instead, and consumers pay for both.

The National Energy System Operator’s own reporting puts the cost of balancing the grid at roughly 2.7 billion pounds in the year to March 2025, with thermal constraints making up the bulk of it, and projects that figure could reach around 8 billion pounds a year by 2030 without faster transmission build [1].

What stands out most in the operational detail is how much of this is being discovered in real time rather than planned for. The frequency event on 23 June has been tied by an independent analyst to known weaknesses in the operator’s demand forecasting. The operator restored frequency by cutting exports to the Netherlands and France, a tool that, once treated as routine rather than exceptional, leaves Britain exposed if its neighbours ever decide to do the same in return [15].

Measuring the mismatch directly

In a manuscript set out elsewhere, currently under review at Environmental Innovation and Societal Transitions and available as a working paper on SSRN, the author lays out a way to compare these mismatches across systems directly rather than describing them one country at a time [4].

The Cliff Intensity Index takes the rate at which baseload capacity is retiring and divides it by the rate at which replacement capacity can actually be integrated, adjusted for real transmission build times and for a friction factor that captures how much governance conditions slow things down further. A reading below 1.0 describes a system where new capacity is arriving faster than the network can absorb it, Britain’s condition. A reading above 1.0 describes the reverse, retirement outrunning replacement, which is closer to what Germany is warning about [4].

On this measure, Germany’s transition sits at roughly 0.27, and Britain’s build-out at a similarly low reading, both consistent with the curtailment and constraint costs they are currently absorbing. South Africa’s provisional reading is 2.16, driven by baseload retiring on a compressed 24-month timeline against a slower pace of grid-ready replacement [4]. A caveat matters here. The manuscript is still under review, and the figure is sensitive to assumptions about the length of that window and the pace of transmission build. It should be read as a serious diagnostic, not a settled number.

South Africa’s own numbers

Whatever view anyone takes of the index, the underlying planning documents are not really in dispute. The Medium-Term System Adequacy Outlook treats a cluster of coal station retirements as non-discretionary, plants that have reached the end of their working life inside the relevant horizon[6]. Minimum Emission Standards compliance becomes binding from 1 April 2030, with no further extensions provided, which could idle additional capacity depending on environmental forbearance decisions [4]. Against that sits a transmission pipeline of replacement capacity whose real contribution depends on how quickly new lines, particularly at the higher voltages required by the country’s generation geography, can be built and energised [9]. Something like 13.7 billion dollars in Just Energy Transition financing is tied to the pace of that transition, adding pressure to get the sequencing right [4].

What manageable actually means

South Africa’s position is not manageable because the numbers are gentle. They are not. It is manageable, in the author’s assessment, because, unlike Germany and Britain at this exact moment, the mismatch is being examined before it has produced a live incident, rather than after.

That advantage only holds if it is used. It means treating transmission lead time as the real constraint on the programme, not a detail to assume away. It means keeping a coal reserve on an explicit bridge, on a schedule tied to replacement capacity actually being energised, the same thing Muller is asking Germany to do, rather than retiring plants against a fixed calendar regardless of what has been built to replace them. It means sequencing institutional reform so it runs alongside physical adequacy rather than ahead of it, since coordination costs among a new transmission entity, a market operator, and private generators are themselves a form of friction the index is trying to capture. And it means publishing the diagnostic and updating it, rather than debating it once and moving on, so that if the numbers start moving in the wrong direction, the country knows before the event, not after.

Germany and Britain are two of the best resourced grid operators in the world, and both are currently managing a version of this problem in public, under pressure, in real time. That is not a reason for South Africa to relax. It is the clearest evidence available that the underlying risk is real, and it is also the strongest argument for why South Africa’s position, difficult as it is, remains one that can still be managed ahead of the event.

References

[1] National Energy System Operator (NESO). 2025 Annual Balancing Costs Report. Published June 2025 under Condition C9 of the NESO Electricity System Operator Licence. Retrieved from https://www.neso.energy/document/362561/download

[2] National Energy System Operator (NESO). Interconnector Trading Restriction, Market Notice. Effective 20 May 2026. Retrieved from https://www.neso.energy/industry-information/balancing-services/trading

[4] Koko, M. South Africa’s 2030 Electricity Capacity Cliff: Institutional Frictions, Sociotechnical Inertia, and the Political Economy of Accelerated Coal Phase-Out. Manuscript under peer review, Environmental Innovation and Societal Transitions. Available at SSRN: https://doi.org/10.2139/ssrn.5794522

[6] National Transmission Company South Africa. Medium-Term System Adequacy Outlook 2026 to 2030. Johannesburg: NTCSA, 2025.

[9] National Transmission Company South Africa. Transmission Development Plan 2024. Johannesburg: NTCSA, 2024.

[12] National Energy System Operator (NESO). Electricity Ten Year Statement: Our Year Round System Needs, Scottish Boundaries. Retrieved from https://www.neso.energy/publications/electricity-ten-year-statement-etys/our-year-round-system-needs

[13] Amprion GmbH. Remarks by Christoph Muller, reported in Amprion CEO Calls for Moratorium on Coal Plant Shutdowns to Avert 24 GW Shortfall. Market Briefs, 2 July 2026. Retrieved from https://www.briefs.co/news/amprion-ceo-calls-for-moratorium-on-coal-plant-shutdowns-to/

[14] Amprion GmbH. Security of supply: what measures Amprion now considers necessary. Netzjournal, 2026. Retrieved from https://www.amprion.net/Netzjournal/Beitraege-2026/Energiewende-und-Versorgungssicherheit-Welche-Massnahmen-Amprion-jetzt-fuer-noetig-haelt.html

[15] Porter, K. NESO cutting exports during a low frequency event may come back to bite us in winter. Watt-Logic, 2 July 2026. Retrieved from https://watt-logic.com/2026/07/02/neso-cutting-exports-during-a-low-frequency-event-may-come-back-to-bite-us-in-winter/

Matshela Koko is a Doctoral Candidate at the Graduate School of Business Leadership, UNISA, and Managing Director of Matshela Energy. He is the former Interim Group Chief Executive of Eskom (2016 to 2017). He writes in his personal capacity.