- [Episode #286] – A Moving Target

Doubters of the transition have always been quick to share doom scenarios about grids losing stability once wind and solar supplied a large share of their power. In the Energy Transition Show’s early episodes, our host Chris noted how defenders of the status quo “have claimed for decades that the grid can’t support more than 3 percent or 5 percent or 20 percent, it’s a moving target, of variable renewables without risking blackouts…”

Years later, reality leaves transition skeptics less and less room to maneuver. So is there really an upper limit on how much wind and solar a grid can handle? In 2025, renewables provided more than 77% of South Australia’s electricity generation, nearly half of it from wind. And for half an hour in April 2026, 98.8% of the power on Britain’s transmission grid came from zero-carbon sources, by NESO’s own measure.

Certainly along the way there have been blackouts blamed on renewables, such as 2016 in South Australia, or Spain and Portugal in 2025. If you only followed the headlines, you’d think the doubters had been right all along.

But grid engineers keep learning how to adapt, and the target keeps moving. In this episode of our documentary series, we start with conversations from the show’s past and how they connect to recent ones about grid stability, including what the official investigation into Spain’s blackout actually found, and how Britain gives its grid inertia without burning fuel.

Featured in this episode, in the order we hear their conversations:

* Paul Denholm, principal analyst at the National Renewable Energy Laboratory, on Episode #58 (2017)

* Julian Leslie, Head of Networks and Chief Engineer at National Grid ESO, on Episode #174 (2022), and Director of Strategic Energy Planning and Chief Engineer at NESO, on Episode #245 (2025)

* Mackay Miller, senior analyst at the National Renewable Energy Laboratory, speaking in a personal capacity, on Episode #2 (2015)

* Jenny Riesz, Principal at the Australian Energy Market Operator, on Episode #39 (2017)

* Ivor Frischknecht, CEO of the Australian Renewable Energy Agency, on Episode #71 (2018)

* Willie Phillips, Acting Chairman of the Federal Energy Regulatory Commission, at the commission’s open meeting on Order 901, October 19, 2023 (“FERC Commission Meeting | October 2023 Open Meeting”). Source: Federal Energy Regulatory Commission. Public domain

* Leonhard Gandhi, Fraunhofer ISE, from the Energy-Charts Talk “Analyse und Bewertung des Stromausfalls in Spanien und Portugal am 28. April 2025” (1 April 2026). In German, with an English voice-over translation by XE Network.

* Professor Janusz Bialek of Imperial College London, interviewed by Dr Giordano Scarciotti on his YouTube channel, Prof Gio, in the video “Why Everyone Got Spain’s Blackout Wrong” (July 24, 2026)

* Wallace Kenyon, PhD candidate at the University of Colorado Boulder, affiliated with the National Renewable Energy Laboratory, on Episode #153 (2021)

* Guy Nicholson, Head of Grid Integration UK, Statkraft, from Modo Energy’s Transmission podcast, “Synchronous compensators, and Stability Pathfinders with Guy Nicholson” (2025)

* Kayte O’Neill, Chief Operating Officer, NESO, from Modo Energy’s Transmission podcast, “Connections, Capacity & Clean Power: Britain’s Grid Reform – NESO” (2026)

Thanks to Fraunhofer ISE’s Energy-Charts Talk, Giordano Scarciotti and his Prof Gio channel, and Modo Energy’s Transmission podcast for permission to use their clips. Every clip in this episode is used with permission, under license, or from the public domain.