Future ‘Black Sky’ power outage is possible and would severely disrupt businesses, Resilience First warn


Following a major power outage on the National Grid on 9 August 2019, Resilience First have warned that a future widespread blackout (a so-called ‘Black Sky’ event) could occur, causing severe disruption to businesses.

Last month, over a million customers were affected by a short loss of power caused by two generating stations going offline at the same time. However, there were knock-on effects across the road, rail and airport networks lasting several hours. An interim report on the outage has been sent to the regulator and a fuller report is expected in a few months.

While this recent incident was a ‘rare’ event, the official National Risk Register (2017) has stated that the likelihood of such an occurrence is rated as 3 out of 5 over the next five years while the impact severity is rated 4 out of 5.

The Register states that ‘an electricity failure across entire regions or the UK as a whole has not happened before,’ but that The National Grid has a recovery process called ‘Black Start’ to recover the network from a total or partial shutdown. However, based on current plans, Black Start recovery could take up to five days with potential for some additional disruption beyond this timescale in the event of significant network damage. Consequences of a national loss of power may include:

• fatalities and physical / psychological casualties;
• disruption or loss of essential services, particularly transport, food, water, fuel, gas,
finance, communications (all types), and education;
• disruption to business (via lost working hours); and
• if blackouts are prolonged, also potential disruption to health care, emergency services and emerging public disorder.’

An excellent examination of how a widespread outage could occur and what the consequences would be are given in a report from a meeting in February 2018 entitled ‘The London Black Sky Seminar//2018: Infrastructure and Societal Resilience to Black Sky Hazards’.

The report concludes: ‘Resilience to Black Sky hazards cannot be achieved by scaling up plans for short-term, localised, power outages. However, the creation of systemic resilience to Black Sky hazards will yield significant benefits for short, medium and long-term resilience planning.’

Lord Harris of Haringey, a speaker at the seminar, said that ‘no service or utility can plan for a Black Sky event on its own, and every sector has to recognise its mutual dependencies on other sectors’.See also Resilience First news feature here.