Solar-powered mobile base stations are not new, but making the most of the electricity they generate remains a challenge. Solar generation varies throughout the day and depends on weather conditions, while mobile networks need a continuous and reliable electricity supply. Batteries can help bridge this gap, but their capacity must also be reserved to keep networks running during power outages.
In September 2026, NTT DOCOMO announced the successful demonstration of its weather-forecast-linked lithium-ion battery control technology in the Philippines, working with PLDT and its mobile subsidiary Smart Communications. The trial marked the first overseas deployment of a technology that DOCOMO originally developed in Japan in 2016.
The demonstration involved two green base stations operating under different conditions. One was located near Metro Manila, where grid electricity was available, while the second was an off-grid site on Cebu Island. Both incorporated solar panels, battery storage and DOCOMO's Energy Management System (EMS) platform, which manages electricity generation, storage and consumption.
What makes the technology interesting is how it manages the batteries. Traditionally, a significant proportion of battery capacity at mobile sites is reserved for emergency backup. While this helps maintain connectivity during electricity outages, it also limits how much surplus solar electricity can be stored and used during normal operations.
DOCOMO's approach uses weather forecasts and expected electricity demand to dynamically adjust the proportion of battery capacity allocated to backup and everyday energy management. When conditions permit, more capacity can be used to store and supply solar-generated electricity, while sufficient reserves must still be maintained to support network operations during outages. The control algorithms were also adapted to reflect local climate and electricity supply conditions in the Philippines.
The results were encouraging. Solar power utilisation efficiency increased from 38% to 61%, an improvement of 23 percentage points. The battery systems also enabled the effective use of 3,905 kWh of surplus solar electricity that would otherwise have gone unused. According to DOCOMO, the demonstration reduced cumulative CO₂ emissions by approximately 2,854 kg during a 100-day validation period between April and July 2026.
DOCOMO already has considerable experience with renewable-powered infrastructure, having deployed 329 green base stations across Japan by the end of March 2026. These installations form part of its wider efforts to reduce network energy consumption and improve resilience. The company has also explored alternative renewable sources, including a self-powered hydropower base station that we previously covered.
From an infrastructure perspective, the Philippine demonstration is particularly relevant because energy availability and reliability can vary significantly between locations. Grid-connected sites may benefit from lower electricity consumption and costs, while remote or off-grid sites can potentially make better use of locally generated renewable energy. Intelligent battery management could also help operators balance energy efficiency with the need to maintain communications during extended power disruptions.
There are still questions around large-scale deployment, including installation costs, battery ageing, forecast accuracy and the amount of backup capacity that can be guaranteed under different operating conditions. The published results do not provide a site-by-site breakdown or quantify the impact on battery lifetime and outage performance.
Nevertheless, the demonstration highlights an important evolution in telecom infrastructure. Making mobile networks more sustainable is not simply about installing solar panels or larger batteries. Increasingly, it is about intelligently managing the energy already available, balancing cost, sustainability and resilience to keep networks operating reliably.
Related Posts:
- Telecoms Infrastructure Blog: NTT DOCOMO Trialled Japan’s First Self-powered Hydropower Base Station
- Telecoms Infrastructure Blog: Electric Vehicles as a Resilient Power Source for Telecom Infrastructure
