2019 UK power cut

2019 UK power cut
Title	2019 UK power cut
Date	9 August 2019
Location	United Kingdom
Type	Power outage
Cause	Equipment failure and lightning strike

2019 UK power cut was a widespread electricity disruption on 9 August 2019 that affected large parts of England, Wales, and Scotland. The incident caused interruptions to National Grid (Great Britain), Northern Powergrid, Western Power Distribution and multiple energy industry stakeholders, prompting responses from Office of Gas and Electricity Markets, Department for Business, Energy and Industrial Strategy and local mayoral offices. The event highlighted interdependencies between transmission system operators, generation plant operators and critical infrastructure authorities such as Network Rail, Heathrow Airport and London Underground.

Background

The UK's electricity system in 2019 relied on a mix of gas-fired power stations, coal-fired power stations, nuclear power stations, wind farms and solar power installations, coordinated by National Grid ESO and governed by Electricity Act 1989-era frameworks. Energy market structures involved Ofgem regulation, balancing mechanisms, capacity market arrangements and bilateral contracts with companies including EDF Energy, SSE plc, RWE, ScottishPower and Drax Group. Transmission networks were owned and operated by entities such as National Grid (Great Britain), while distribution networks included UK Power Networks, Scottish and Southern Electricity Networks, Northern Powergrid and Western Power Distribution. The UK's resilience planning drew on lessons from prior incidents like the 2003 Italy blackout, 2012 India blackouts, and infrastructure reports by Committee on Climate Change and National Infrastructure Commission.

Incident timeline

At approximately 08:00 BST on 9 August 2019, a simultaneous loss of generation and infeed occurred, triggering automatic protections across the Great Britain transmission network, with frequency deviations recorded by National Grid ESO and system telemetry used by Balancing Mechanism Reporting Service participants. Within minutes, large consumers and distribution operators including Network Rail, London Underground and Heathrow Airport reported outages, while regional distribution companies such as UK Power Networks and Western Power Distribution began fault diagnostics. Around 08:30, restoration teams from Electricity North West and ScottishPower mobilised to reinstate supply to affected substations, coordinating with emergency services including Metropolitan Police Service, Greater Manchester Police and local fire and rescue services. By midday, National Grid indicated progressive recovery with islanded systems re-synchronised and emergency balancing by gas turbine and diesel generator units contracted under emergency instructions.

Causes and technical analysis

Initial operational data identified a simultaneous loss of two major Combined Cycle Gas Turbine units and a failure of an HVDC link and several substation components, with a coincident lightning strike reported near a substation feeding the London area. Engineers from National Grid ESO, plant operators such as Uniper

and equipment manufacturers including Siemens and ABB analysed protection relay operations, automatic governor responses, and under-frequency load-shedding schemes. Detailed oscillography and phasor measurement unit outputs were examined alongside plant governor response curves, excitation system performance, and automatic protection settings derived from ENTSO-E best practice. Investigators assessed whether cascade tripping, loss of synchronism, or erroneous relay operation at transmission substations such as Walham and Hampton contributed, and whether ancillary services procurements under the Capacity Market and balancing mechanisms affected system resilience.

Impact and response

The outage disrupted rail services run by operators including Avanti West Coast, Great Western Railway and Southern Railway, caused signalling failures on lines managed by Network Rail, and affected airport operations at Heathrow Airport and regional airports. Hospitals such as Guy's Hospital and Royal Free Hospital activated contingency plans, deploying on-site backup generators and incident management teams involving NHS England and local clinical commissioning groups. Telecommunications firms including BT Group and Vodafone reported service degradations where local sites lost mains power, prompting mobile generator deployments coordinated with local authorities and Civil Contingencies Secretariat contacts. Supply chain and retail operations for supermarkets like Tesco, Sainsbury's and Marks & Spencer experienced temporary closures. Political leaders including Prime Minister and the Secretary of State for Business, Energy and Industrial Strategy issued statements and met with operators from National Grid ESO and executives from utilities.

Investigations and inquiries

Regulators Ofgem and BEIS launched formal inquiries, while National Grid ESO convened technical review groups with stakeholders including ENTSO-E, transmission owners such as National Grid Electricity Transmission and distribution companies like Northern Powergrid. Independent review panels comprised experts from University of Manchester, Imperial College London and international consultants from firms such as Black & Veatch and PA Consulting examined protection settings, market incentives for inertia and frequency response, and compliance with standards set by Institute of Engineering and Technology and British Standards Institution. Parliamentary scrutiny included sessions by the Business, Energy and Industrial Strategy Committee and evidence submissions from CEOs of EDF Energy and ScottishPower.

Policy and infrastructure changes

Following recommendations, policymakers advanced procurement and reform of ancillary services including enhanced frequency response contracts, incentives for fast-acting battery energy storage deployments by firms such as Tesla, Inc. and Powervault, and grid code amendments administered by ENA and Ofgem. Investment plans accelerated grid reinforcement projects involving HVDC links, substation resiliency upgrades, and schemes proposed by National Grid Electricity Transmission and distribution network operators to harden critical nodes. Strategic collaboration with bodies like National Infrastructure Commission and initiatives under the Ten Point Plan for a Green Industrial Revolution aimed to increase low-carbon flexible capacity, integrate distributed energy resources, and improve emergency preparedness across sectors including rail and healthcare.

Category:Power outages in the United Kingdom Category:2019 in the United Kingdom