• Japanese operator SoftBank Corp is aiming to achieve net zero emissions across its entire supply chain by 2050
• As part of its efforts it is using hybrid solar and wind power generation and AI to make its radio access network greener

Like every mobile operator around the world, Japan’s SoftBank Corp wants to become more energy efficient and environmentally friendly – it has a target to achieve net zero emissions across its entire supply chain by 2050 – and it is using renewable energy sources (for electricity production) and AI (to manage electricity consumption) in its radio access network (RAN) to help meet its goals. 

Targeting energy consumption in its RAN makes sense for the operator, as its mobile base stations account for more than half of the company’s entire energy consumption. 

Its electricity production initiative comes in the form of a self-powered base station that uses renewable energy from solar and wind power that is currently being tested in Ichihara City, Chiba Prefecture, and which can produce one-third of the power it needs from its hybrid renewable energy sources. The setup can also operate independently for an unspecified amount of time during power outages. 

For wind power generation, SoftBank is using a small lens wind turbine (3kW model). “This wind turbine is equipped with a diffuser that efficiently collects and accelerates wind, and is characterised by its high power-generation efficiency even at low wind speeds of around 3m/s [metres per second], achieving approximately 2 to 3 times the power-generation efficiency of a typical wind turbine of the same size,” noted the operator in this announcement (in Japanese). “In addition, its small installation area makes it suitable for installation on remote islands and mountainous areas,” it added. 

SoftBank is evaluating the results of the tests and is considering further such pilot deployments elsewhere in Japan, starting in the next fiscal year (from April 2026), but it regards the hybrid setup as “a new model for decarbonising communications infrastructure.”

Sleep state automation

SoftBank has also developed, and has started deploying, an AI-enabled system that dynamically controls the sleep state of base stations to maximise power savings. “This system automatically transitions some cells into sleep (low-power consumption state) during periods of low traffic, reducing power consumption while maintaining communication quality,” noted the operator. 

It added: “By using AI to analyse people flow and communication traffic, target cells are determined while maintaining communication quality. Base station sleep control must be performed on the premise that the traffic of the target cell is covered by other surrounding base stations and that congestion does not occur at those surrounding base stations. Until now, to maintain a stable service area even during sleep, target cells were determined under strict conditions, such as surrounding base stations being in the same building and with the same antenna direction. However, AI analysis makes it possible to expand the target cells while maintaining communication quality. With this function, it is expected that the number of sleep target cells will be expanded from approximately 14,000 to approximately 24,000.”

In addition, the AI is able to dynamically adjust the threshold for putting a base station into sleep mode and automatically enable that state, offering greater efficiencies over the uniform settings for all base stations. This approach is expected to increase the sleep time per base station by approximately 1.4 times. 

SoftBank expects to reduce power consumption by approximately 5 million kWh per year as a direct result of deploying this system. 

SoftBank is also aiming to generate 100% of the electricity used in its business activities from renewable energy sources by fiscal 2030. For base stations, it is aiming to switch to essentially renewable energy supplied by SB Power Corp (which is a SoftBank Corp subsidiary) – it is already sourcing more than 90% of its base station electricity from renewable energy sources. 

- Ray Le Maistre, Editorial Director, TelecomTV