A complete failure of mobile networks during recent power cuts has heightened fears about whether people can reach emergency services during blackouts.
Burgess Hill — a town in Mid Sussex similar in size to the City of Westminster — was hit by two lengthy power cuts last week. Each involved the town’s mobile phone reception being wiped out for several hours.
If such power cuts happened in densely populated London, hundreds of thousands of people could be without mobile reception.
In Burgess Hill, schools forced to close because of the power cuts were unable to contact parents. Meanwhile, residents had to drive for miles outside of the town to make important calls.
One Mid Sussex resident, Benjamin Howe, has written to the town’s MP, Mims Davies, asking her to investigate the widespread mobile outages. He said “more people are relying on mobile phones to contact the emergency services than ever before”.
Figures from telecoms regulator Ofcom state that more than 70 per cent of 999 calls are made from mobile phones. A lack of mobile reception will soon become even more critical as BT switches off the Public Switched Telephone Network (PSTN). This keeps landline phones powered during blackouts.
Lack of power backups
A former BT executive told the Evening Standard that although some mobile base stations do have battery or diesel-generator backups, these are rare in urban areas.
“You put in as little equipment as you can get away with, because landlords say ‘if you want redundant power, we’ll charge you more,’” said the former executive, who asked not to be named. “It’s really difficult to get [power] redundancy in urban areas. Building loads of diesel generators in urban locations is not going to get planning permission.”
Even on sites where battery backups exist, they may keep mobile networks up and running for only a short period, the former BT executive said. That can lead to widespread mobile network blackouts when the power fails for prolonged periods, as it did in Sussex.
“If you lose power to one building [containing a mobile mast], you might lose capacity but nearby masts will provide redundancy and coverage will be OK,” said the former BT executive. “If a power failure takes out an entire city or towns, it will take them all down and you’ll get nothing.”
Ofcom’s Connected Nations 2022 report revealed how fallible the battery backups could be, as witnessed during Storm Eunice last February.
“Some mobile mast sites are backed up with an on-site battery designed to last between 15 minutes and six hours,” it reads. “However, because many of the power outages were prolonged, and in excess of the battery capacity, it led to mobile cells ceasing to operate and customers losing access to their mobile services.”
Lack of regulation
Mobile networks are under no legal obligation to provide backup for power failures. An Ofcom spokesperson confirmed that “there is no regulation specifically requiring power backup to mobile mast sites. However, network providers should continue to ensure they are taking all other necessary measures to maintain uninterrupted access to emergency organisations.”
A spokesperson for BT-owned EE said: “BT Group has well-established contingency plans for a variety of power-loss scenarios to ensure we can keep our networks connected. From a mobile perspective, this includes backup generators and battery backup at a number of mobile mast sites, as well as overlapping coverage in many locations where backup power isn’t available.
“However, given the unpredictable location, extent and duration of power outages, they will in certain instances have a localised impact on mobile networks.”
A Vodafone spokesperson put last Thursday’s service failure in Burgess Hill down to planned maintenance. The spokesperson added that its network “has built-in resilience to cover temporary power outages with extended backup for critical sites. We have also invested considerably in our network in order to keep serving our customers during such periods.”
