More evidence needed to establish 5G’s green credentials

Given the relatively low-powered intrinsic nature of 5G masts and other essential technology, there is an expectation that 5G will be a green technology – but such a perception is a not fully backed up, says a review of the evidence on 5G energy use impacts by academics at the University of Sussex Business School.

In the published study, Renewable and sustainable energy reviews from the Sussex Energy Group and funded by the Centre for Research on Energy Demand Solutions, academics from the university’s Science Policy Research Unit examined whole-network-level assessments of the operational energy use implications of 5G, the embodied energy use associated with 5G, and the indirect energy use effects associated with 5G-driven changes in user behaviour and patterns of consumption and production in other sectors of the economy.

The review found what was described as a surprising lack of assessments of the energy use implications of 5G at the whole-network level. It also observed that assessments that do exist tend to produce relatively encouraging findings – suggesting that the improved energy efficiency of 5G can ensure that overall network energy consumption remains flat or falls despite high rates of data traffic growth. But the research authors cautioned that a number of these studies fail to fully disclose key data and assumptions on which their findings are based.  

The research paper also warned that current studies into 5G energy use fail to properly account for not only the impact of the embodied energy associated with network infrastructure and user devices, but also direct rebound effects associated with 5G-driven changes in mobile device user behaviour. There was also a perceived lack in assessing wider indirect energy use effects, including the scope for 5G to enable energy savings in other areas of economic and social life – the so-called “enablement effects”.

The study noted that the need for large-scale infrastructure updates every decade to accommodate new-generation mobile networks and the even shorter lifespan of smartphones leave a significant environmental impact that must be combated through the modular design of network infrastructure, right-to-repair legislation and bans on planned obsolescence from manufacturers.

The review found that industry scenarios tend to emphasise the energy- or emissions-saving potential of increasing adoption of information and communication technologies (ICTs) due to the optimisation of processes and systems and structural changes as virtual processes replace physical processes.

But the Sussex Energy Group researchers warned that even though some estimates suggest that mobile communications enable emissions-savings 10 times greater than the footprint of the industry itself, the scope for 5G specifically to produce such enablement effects has not yet been comprehensively assessed, nor has whether such effects would exceed the operational and embodied energy use of 5G, as well as any rebound effects it may produce.

It also emphasised that existing academic and industry studies into the energy use implications of 5G fail to provide a comprehensive overview of the overall energy use impacts of 5G and overlook three potentially significant issues that broader research on the energy use impacts of other ICTs suggests could be significant.

In addition, the academics warned that the widespread adoption of unlimited data subscriptions for 5G users and the facilitation of advanced and data-intensive mobile services such as virtual reality (VR)  and more sophisticated mobile gaming could encourage energy-intensive user practices, contribute to ever-growing levels of data traffic, and counteract the energy-saving potential of 5G efficiency improvements.

The study also recommended that network operators and service providers raise awareness among users and make information more transparent about the energy use implications of different practices, such as streaming video over Wi-Fi rather than mobile data or sending a message by SMS rather than instant messaging. App developers were recommended to factor sustainability and energy-efficiency considerations into the earliest design stages.

The review also suggested that work on the energy use implications of 5G has so far overwhelmingly focused on the energy required to power mobile phone networks. However, it said the energy required to manufacture and install network equipment and manufacture mobile phones is a potentially important part of the puzzle that seems to be routinely overlooked in assessments of 5G’s energy use. 

“There has been insufficient ‘user-centric’ work focusing on the relationship between 5G energy use and user behaviour, leaving unanswered questions about how and under what conditions 5G might become more or less energy-intensive,” said Benjamin Sovacool, professor of energy policy in the Science Policy Research Unit at the University of Sussex Business School.

“We also need greater resource and focus given over to the kinds of strategy that might be pursued by app designers, mobile operators, technology firms and governments aimed at reducing energy-intensive behaviours, particularly around flat pricing structures, declining per-bit data prices and the proliferation of unlimited data subscriptions which encourage wasteful practices and generate direct rebound effects.”

On a brighter note, the report recognised there are encouraging signs that the industry is starting to take the issue of embodied energy more seriously, and the researchers said they hope to see this continue as the industry starts to look towards standardisation processes for 6G.