Vodafone UK sets sights on cutting energy use amid data tsunami

Data traffic carried on Vodafone UK's network has soared threefold since 2019 as the country's smartphone addicts have raided the gigabyte cupboards. What's surprising is that Vodafone's energy consumption over this period has remained flat. Either data gluttony barely moves the needle on the electricity meter or Vodafone has been switching off the lights and making fewer mugs of tea.

There is a smidgen of truth in both. "Decoupling" is a word telcos usually reach for when discussing the separation of hardware from software in new-look networks, but Vodafone uses it to describe the state of relations between data traffic and energy use as well. Thanks to investment in more efficient technologies, and efforts to retire or euthanize older, energy-guzzling ones, a tsunami of gigabytes has not brought a corresponding surge in kilowatt hours. It leads Andrea Dona, Vodafone UK's chief network officer, to express optimism energy use can even be lowered in future.

Activities so far have included the decommissioning of what Dona referred to as "energy-hungry legacy equipment" during an update with analysts and reporters at Vodafone's London offices this week. The sun is setting on 3G, an aging mobile standard, and Dona believes 2G could also be turned off nationwide by 2030. In time, these shutdowns will free up spectrum for better-performing 4G and 5G technologies.

Figure 1: One of Vodafone's self-powering masts, plus a bonus cow.
(Source: Vodafone)

The difference is marked, according to Dona. For every terabyte of network data, 4G consumes only 35% as much energy as 3G, and 5G nibbles only 7% as much. "That shows we need to shift our frequencies to be used in new technologies so we can get a reduction in consumption," said Dona. "Some people challenge me and say 5G consumes more. It does consume more, but per kilowatt per megahertz per hertz it is much more efficient."

Vodafone's latest 5G equipment even includes an artificial intelligence feature that powers down radios during quiet periods and sends them into a deep-sleep mode when there is no traffic on the network. An active antenna it sources from Ericsson is 40% more energy efficient than older equipment is during busy hours, said Dona.

Out with the old

Perhaps even more impressive are the operator's efforts to rip out older telephone-exchange equipment acquired with its £1 billion (US$1.25 billion, at today's exchange rate) takeover of Cable & Wireless Worldwide in 2012. Overall, it has been able to remove 30 legacy networks comprising 116 voice switches and 864 data nodes, saving itself about 167 million kilowatt hours, roughly 3% of Vodafone Group's entire energy consumption in the 2021 fiscal year. That equates to tens of millions of pounds per year in run-rate savings, said Dona.

In the last two years, the moving parts include a 7% drop in energy use on Vodafone's fixed networks along with a 4% increase on the radio access network (RAN) – not bad considering the gigabyte explosion triggered by smartphone customers – for stable consumption altogether. "I would expect conservatively it should not go up if I continue decommissioning of products," said Dona, outlining the various other steps Vodafone has taken to be greener and more efficient.

Figure 2: Engineers install photovoltaic panels at a Vodafone exchange in Gloucestershire.
(Source: Vodafone)

They include investment in facilities powered by solar energy or wind. One of its mobile telephone exchanges in Gloucestershire now features 720 solar panels intended to supply around 12% of its energy, and Vodafone plans to kit out numerous other sites in the next two years. A mast in Pembrokeshire features a wind turbine, resembling a miniature watermill out of its natural habitat, that self-powers the equipment in the right conditions.

"Between 21 and 23 March, we had winds higher than the average of eight meters per second and reaching 10 meters per second, and that is enough to generate almost the whole requirement of the site – roughly 80 kilowatt hours per day," said Dona. "We managed to produce 70 of that through wind."

Keeping Greta happy

Deployed more extensively, such technologies could help Vodafone to meet its 2027 goal of being "net zero" on carbon emissions under Scopes 1 and 2, the categories over which it has more direct control. Since July 21, it claims to have been entirely powered by renewables, but this is largely thanks to power purchase agreements it has struck with energy suppliers. Vodafone, however, still buys energy from the grid, not directly from those suppliers. Its emissions therefore look much higher using the location-based method, which measures the make-up of the grid, than they do using Vodafone's preferred market-based system.

For the UK business, the figure for Scope 2 market-based emissions was just 23% of that shown for location-based emissions during the fiscal year that ended in March 2022 (more recent data is currently unavailable). But the wider use of self-powered masts and solar panels at exchanges would directly cut Vodafone's reliance on the grid.

Much harder will be lowering Scope 3 emissions – those generated upstream and downstream by Vodafone's suppliers and customers. Across the entire group, Scope 2 emissions came to about 2.3 million tons of carbon dioxide for the fiscal year that ended in March 2022. Scope 3 emissions were a temperature-raising 9.2 million, a disparity executives would not want publicized within earshot of Greta Thunberg or her acolytes.

What can be done to reduce it? "What we're also doing beyond our direct area of influence is that every procurement needs to ensure that every single member in the chain has their share of commitment," said Dona. But he also thinks regulatory authorities could support efforts by attaching less onerous conditions to the shutdown of older technologies.

"You need evidence you have communicated to all customers and ensured vulnerable customers are safeguarded, but there comes a point where we also need help," he said. "Certain old technologies just need to be switched off. If we hang onto everything it becomes quite burdensome."

Open and measurable

Dona is, unsurprisingly, relatively upbeat about open RAN, a concept Vodafone has helped to pioneer. In the west of the UK, it is piecing together products from different suppliers, instead of buying pre-assembled kit from one big vendor, as it has previously done. This allows it to assess the energy efficiency of discrete parts, a difficult task when someone else has the responsibility for integration.

So how does open RAN measure up against traditional kit overall? Dona reports "not much difference" so far, arguing that more software-based architecture does mean fewer truck rolls and other efficiency benefits. The caveat is a rise in energy consumption that Vodafone saw when running baseband software on general-purpose processors, as opposed to more customized silicon. At facilities in Malaga, Vodafone Group is currently assessing the pros and cons of different chip technologies in this part of the RAN.

Despite all its efforts, Vodafone Group's electricity bill rose 11% for the fiscal year that ended in March 2022, to roughly €846 million ($927 million), after a sharp rise in prices caused by earlier lockdowns and the ongoing war in Ukraine. The worst of the supply crunch now seems to be over, but energy's share of telco operating costs – about 5% at the average big European operator, according to Moody's – shows why cutting use remains such a priority. For the foreseeable future, that probably won't change.

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— Iain Morris, International Editor, Light Reading