The telecoms regulator, Ofcom, has today published the results of a recent study it conducted into the costs of improving power resilience at UK mobile network sites (masts etc.). This finds that the cost of ensuring “almost everybody” could maintain access to the emergency services for up to 4 hours, in the event of a power cut, would be approx. £1bn.
Communications providers in the UK currently have a legal obligation to identify, prepare for and reduce the risk of anything that compromises the availability, performance or functionality of their networks. But such networks are highly complex and outages can still occur, with Ofcom warning that the consequences of these are “likely to become more severe as society becomes increasingly dependent on them to function.”
The regulator has thus been working to improve network resilience since 2023, and they’ve already made some progress (here). But the issue of improving power backup for Radio Access Networks (RAN), such as at the mobile mast sites operated by Three UK, EE, Vodafone and O2, has required further work. Mobile operators are also known to have balked at the potential costs of deploying national battery backup (here).
For example, Ofcom’s original Call For Input (CFI) on the matter asked questions about the feasibility of mobile operators installing a minimum 1 hour of battery backup at RAN sites. But Ofcom’s own illustrative example suggested that to install this on such sites, where power backup is likely to be feasible, could cost in the region of £0.9 – £1.8bn (this would end up being passed on to consumers as higher prices).
Due to the challenges and high costs involved, the regulator didn’t initially consider it “proportionate” to include such a measure in last year’s updated guidance and instead set about conducting a deeper analysis to “determine if additional resilience measures are needed“. The original costing estimate was also derived from a high-level (limited) understanding of the total number of UK masts, which required some refinement.
Ofcom has today published a new technical report into Mobile RAN power resilience, which reveals some very interesting findings.
Key Findings – Mobile RAN Power Resilience
The output from the modelling and analysis suggests that:
a) For short duration power outages up to around 1 hour, around two thirds of the population would be able to make emergency calls. This level of protection is enabled through the power back-up of around 20% of all mast sites in the UK up to at least one hour, coupled with the fact that mobile phones will roam onto available networks to make an emergency call, so are not dependent on their home network.
b) As the duration of an outage increases fewer consumers can make emergency calls: only around [REDACTED] could make an emergency call in the event of a power outage lasting up to 6 hours. This is because far fewer (5%) sites [REDACTED] have backup facilities of at least 6 hours.
c) We estimate that the costs to upgrade mobile networks to ensure almost everyone can maintain access to the emergency services for up to 4 hours would be approximately £1 billion. As we noted in our CFI, Ofgem data indicates that the majority (approximately 90%) of power outages last between 3 mins and 3 hours.
d) Further enhancements or network hardening to increase the duration of protection and/or to allow more services (such as data [broadband] connectivity or the ability to make calls to any number rather than simply 999) would incur significantly higher costs.
e) Technological innovation may provide alternative solutions to maintain connectivity, such as the increasing availability of ‘Direct to Device’ satellite communication. The geographic extent, capacity and timescales of such approaches need further investigation before they can be considered viable alternatives to current mobile backup measures.
f) Internationally we have not seen a common consensus emerge on how to ensure resilience on the RAN, with individual countries adopting different positions depending on their circumstances. For example, challenging weather conditions prompted Australia and Norway to implement mobile network power backup, with Australia taking a voluntary approach (12 hours for a limited number of sites) and Norway mandating it (2 hours, with 4 hours in rural areas), while Switzerland has considered plans to mandate up to 72 hours of backup with potential service restrictions.
The data and insights contained in this report do not form a cost/benefits analysis (CBA) and do not quantify the value of different levels of resilience considered. But the information is intended to help inform further discussion on power resilience in the mobile network and power backup of MNO mast sites.
Ofcom are now considering what their next steps in this work should be and will set that out at a later date. A solid solution still seems to be some distance away. The report also included a table showing the estimated ‘aggregate’ cost range to improve RAN resilience, UK wide, across all mobile operators and over different time periods (note: the £1bn estimate for up to 4hrs mentioned earlier only covers access to the emergency services).
