Energy Savings in Base Stations with KDDI

KDDI’s combined scope 1 and 2 emissions in the 2023 financial year were approximately 950,000 tons, of which around half were related to energy use in base stations. 3G shutdowns have significantly reduced power consumption since April 2022 however, further saving measures remain an important challenge. KDDI is facing this challenge by: 

Sleep Function

At the end of March 2023, KDDI introduced a sleep function for base stations to reduce energy use. Analysing traffic trends of each base station, certain radio waves can be temporarily paused without affecting customers’ communication during low traffic hours, such as late at night. The sleep function reduces 30% of power consumption at maximum. 

Sustainable Base Stations 

From May 2023 KDDI started using solar panels on base stations. Solar panels around the base stations autonomously secure power and supply all the power required for operating a single base station on sunny days. At night, the power supply is automatically switched to CO₂ free electricity provided by a KDDI Group company. 

Thin, Lightweight, and Bendable Solar Cells for Base Stations 

In February 2024, KDDI began a trial of pole-type base stations utilising Perovskite and CIGS bendable solar cells. They have been planning to expand pole-type and building-installed base stations utilising solar panels in limited lot areas, where installing conventional silicon solar panels is challenging. The next-generation perovskite solar cells have high power conversion efficiency (20% or more) and are thin, light, and flexible. CIGS solar cells can also be bent and are already commercially available with a proven track record in power generation and production.  

By wrapping thin-film solar cells around eight cylindrical mounting structures and placing them slightly away from the utility pole, the impact on cable wiring and other elements on the pole is minimised, allowing for the maximisation of solar cell power generation efficiency. 

Combining Perovskite-type and CIGS-type solar cells could supply up to 40% of the power generation needs for base station operations. After a one-year trial, commercial deployment by the late 2020s is on KDDI’s roadmap. 

Collaboration with a power generation company and startups 

KDDI Group includes a company developing and operating renewable energy generation facilities.  Since December 2023, the company, au Renewable Energy, has been supplying solar energy to KDDI base stations in greater Tokyo. KDDI also supports startups engaged in developing new technologies for climate change through their Green Partners Fund. 

KDDI aims to achieve zero CO₂ emissions 24/7 through sustainable base stations utilising solar panels and renewable energy.