On April 28, 2025, a massive power outage plunged Spain and Portugal into darkness, affecting millions and disrupting essential services across the Iberian Peninsula. The blackout, one of the most significant in recent European history, highlighted the vulnerabilities in modern power grids, especially as they transition towards renewable energy sources.While the immediate focus was on restoring electricity, the incident brought to the forefront the critical process of “blackstart” which is the method by which power grids are restarted without relying on external electricity.
The Iberian Blackout: A Brief Overview
At12:33 PM CEST, the power systems of Spain and Portugal experienced a total blackout. The outage was preceded by two significant oscillations in the European power grid, leading to a sudden loss of 2,200 MW of power production in southern Spain. This loss triggered a cascade of failures, resulting in the disconnection of the Iberian grid from the broader European network. Restoration efforts began with the reconnection to France’s power grid at 12:44 PM and concluded by 4:00 AM the following day. Investigations are ongoing to determine the exact causes.
What is Blackstart?
Blackstart refers to the procedure of restoring a power grid to operation without relying on the external electric power transmission network. In the event of a total or partial shutdown, blackstart-capable power stations are essential for “jump-starting” the grid. These facilities can initiate operations independently and gradually energize other power stations and substations, re-establishing the interconnected system.
The Blackstart Process
- Initiation: Blackstart-capable units, often hydroelectric or certain thermal power plants, start up using on-site generators or batteries.
- Energising the Grid: Once operational, these units supply power to nearby substations and other non-blackstart-capable plants, enabling them to start.
- Grid Synchronisation: As more units come online, the grid is gradually re-energised, ensuring frequency and voltage stability.
- Full Restoration: The process continues until the entire grid is restored, with careful coordination to prevent overloads or further outages.
Aberthaw Power Station: A Personal Reflection
When I was very young I had the opportunity to visit the Aberthaw Power Station in South Wales, one of the UK’s blackstart-capable facilities. Commissioned in 1971, Aberthaw, a Welsh Coal fired station, played a pivotal role in ensuring grid reliability, especially during emergencies. Its ability to operate independently made it a cornerstone in the UK’s energy resilience strategy. Although the station ceased operations in 2020, its legacy underscores the importance of maintaining blackstart capabilities within our energy infrastructure.
Modern Challenges and the Future of Blackstart
The transition towards renewable energy sources, while environmentally beneficial, presents challenges for blackstart procedures. Unlike traditional power plants, many renewable installations lack inherent blackstart capabilities. This shift necessitates the development of new technologies and strategies, such as battery storage systems and advanced grid-forming inverters, to ensure rapid and reliable grid restoration.
The recent blackout in the Iberian Peninsula serves as a stark reminder of the complexities involved in maintaining and restoring power in modern grids. As we continue to embrace renewable energy, it’s imperative to invest in blackstart capabilities and infrastructure to safeguard against future outages. By understanding and enhancing these systems, we can ensure a resilient and reliable energy future for all.
