It was a Friday afternoon rush hour that no energy executive wants to see. On August 9, 2019, nearly one million people across England and Wales lost power. Trains ground to a halt, traffic lights failed, and a hospital in Ipswich lost its main supply.
In the immediate aftermath, fingers pointed squarely at the National Grid Electricity System Operator (ESO). The questions were sharp and aggressive. How could a single lightning strike cause such chaos? Why did the backup systems fail? Is the grid too fragile to handle renewable energy?
John Pettigrew, the CEO of National Grid, stepped into the firing line to respond. His defense of the network offers a fascinating case study in the tension between engineering reality and public expectation.
The Incident: A System Under Stress
To understand the criticism and the CEO’s response we first have to look at the mechanics of the failure. The grid operates on a delicate balance. It must maintain a frequency of 50Hz.
That afternoon, a lightning strike hit a transmission circuit. This is a routine event; the grid gets hit by lightning hundreds of times a year. Usually, the protection systems clear the fault in milliseconds.
However, this time was different. The strike triggered a near-simultaneous trip at two major generation sites:
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Hornsea One: A massive offshore wind farm.
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Little Barford: A gas-fired power station.
The combined loss of generation caused the frequency to plummet to 48.8Hz. This is the danger zone. To save the wider grid from a total collapse, the automatic Low Frequency Demand Disconnection (LFDD) scheme kicked in. It cut off power to 5% of the demand to balance the books. The system worked as designed, but the disruption to the public was immense.
The Wave of Criticism
The backlash was immediate. Andrea Leadsom, the Business Secretary at the time, demanded an urgent review. Ofgem, the energy regulator, opened an investigation.
The primary criticism was not that the lights went out, but who was cut off. Critical infrastructure, including major rail lines like Thameslink and Newcastle airport, lost power. Critics argued that the “load shedding” list was outdated and dangerous.
Furthermore, industry experts questioned whether National Grid was holding enough “inertia” (backup stability) on the system. With the shift away from heavy coal and gas turbines to lighter wind and solar, the grid is physically lighter and more prone to rapid frequency changes.
Pettigrew’s Defense: ” The System Worked”
John Pettigrew’s response was measured but firm. He did not apologize for the engineering logic. He argued that the system did exactly what it was programmed to do: it sacrificed a limb to save the body.
“The protection systems worked,” Pettigrew stated in interviews following the event. He emphasized that while the disruption was regrettable, a total uncontrolled blackout would have been catastrophic and could have taken days to restore.
His core arguments focused on three points:
1. Rarity of the Event Pettigrew described the simultaneous loss of two unrelated generators as a “rare and unusual” event. The system is secured against the single largest loss of load. Losing both a gas plant and a wind farm at the exact same second was, statistically, an outlier that exceeded standard security planning.
2. Speed of Response He highlighted the speed of the automated response. The frequency drop was arrested in seconds. The grid stabilized quickly, and power was restored to the distribution networks within 45 minutes. The lingering chaos on the trains was due to the internal systems of the trains tripping and requiring manual resets, not a lack of grid power.
3. Investment in Stability Responding to claims that the grid was under-invested, the CEO pointed to the billions spent on network upgrades. He argued that building a system capable of withstanding any theoretical combination of failures would result in astronomical bills for consumers. There is always a trade-off between absolute gold-plated security and affordability.
The Role of Gas in a Changing Mix
The URL of this story sits under our “Gas” category for a reason. The failure of the Little Barford gas station was a key component of this crisis. It highlighted that even “firm” fossil fuel generation is prone to technical trips.
The incident sparked a debate about the role of gas in a net-zero future. Gas turbines provide inertia the heavy spinning mass that helps stabilize frequency. As we rely more on wind (which has no physical inertia) and interconnectors, the grid becomes more volatile. Pettigrew’s defense subtly underscored the need for new markets for stability services, rather than just relying on old thermal plants.
The Aftermath and Lessons Learned
While the CEO stood by his engineers, the organization accepted that changes were needed. The subsequent investigation led to significant reforms.
National Grid ESO has since accelerated its Pathfinder projects to source stability from new technologies, such as synchronous condensers and grid-forming batteries. They also reviewed the LFDD lists to ensure that trains and hospitals are better protected from automatic disconnects.
Conclusion
John Pettigrew’s response to the criticism was a lesson in technical communication. He had to explain complex electrical engineering concepts to an angry public and a skeptical government.
While the “system worked” defense was technically accurate, the event proved that the definition of a working system needs to evolve. As we move toward a decentralized, renewable-heavy grid, the margins for error are getting tighter. The blackout was a wake-up call that old assumptions about risk and reliability no longer apply in the new age of energy.
