AT TOKYO and elleThermo Succeed in Proof‑of‑Concept Power Generation
Using Waste Heat from Operational Data Center Equipment

AT TOKYO Corporation (Head Office: Koto‑ku, Tokyo; President & Chief Executive Officer: Tatsuya Izumida; hereinafter “AT TOKYO”) and elleThermo, Ltd. (Head Office: Minato‑ku, Tokyo; Representative Director & Co‑CEO: Sachiko Ubukata ; hereinafter “elleThermo”) announce the successful completion of a proof‑of‑concept (PoC) power‑generation test conducted inside operational data centers, using elleThermo’s thermal energy conversion technology, a Semiconductor-sensitized Thermal Cell (hereinafter “STC”).

In this PoC, AT TOKYO and elleThermo jointly deployed STC, elleThermo’s thermal energy conversion device, and conducted verification tests for power generation using waste heat within AT TOKYO’s operating data centers. This PoC represents the first demonstration to verify STC using actual data center equipment, indicating the potential to utilize data center waste heat as a form of “new renewable energy” in the future.

The PoC was conducted at AT TOKYO’s Chuo Center (CC1) and Chuo Center #2 (CC2), both of which are currently in active operation. STC devices were installed in hot-aisle areas around machine rooms and air-conditioning mechanical rooms, as well as inside UPS (uninterruptible power supply) rooms. The verification utilized waste heat generated by servers and other facilities, ranging from the upper 30s to above 40°C, either directly or indirectly, converting the thermal energy into electricity and charging secondary (rechargeable) batteries.

As a result of the PoC, it was confirmed that electrical power can be generated from thermal energy and used to charge secondary batteries at all installation sites. The project quantitatively evaluated differences in power generation characteristics depending on the installation environment, demonstrated the convertibility of data center waste heat into electrical power, and highlighted new possibilities for the effective utilization of previously unused energy.

Through this PoC, AT TOKYO and elleThermo have clarified the feasibility of utilizing waste heat generated in data centers for electricity generation. Both companies will continue pursuing improvements in energy efficiency and energy conservation through the effective utilization of waste heat in data centers, with the aim of reducing environmental impact and contributing to the realization of a sustainable society.

About the Semiconductor-sensitized Thermal Cell (STC)

STC is a technology that replaces the photoexcitation of dyes in dye‑sensitized solar cells with the thermal excitation of semiconductors, enabling direct power generation from low‑temperature heat. As it can operate at around room temperature, it is expected to have a wide range of applications in both household and industrial fields.
Product Information:https://ellethermo.com/technology_en

Company Overview

AT TOKYO Corporation

Head Office: 5-6-36 Toyosu, Koto-ku, Tokyo, Japan
Representative: Tatsuya Izumida, President and Chief Executive Officer
Established: June 26, 2000
Business Description: Data center business that centrally manages information and communication systems (Registered Telecommunications Carrier)
Corporate Website: https://www.attokyo.com
ATBeX Portal Site: https://atbex.attokyo.co.jp/

elleThermo, Ltd.

Head Office: Institute of Science Tokyo, Campus Innovation Center INDEST, 3 3 6 Shibaura, Minato ku, Tokyo
Representative: Sachiko Ubukata, Representative Director & Co CEO
Founded: February 22, 2023
Business Overview: Social implementation of power supply systems utilizing unused waste heat, based on STC (Semiconductor-sensitized Thermal Cell) as the core technology
Corporate Website: https://ellethermo.com/
Review Article:
Sachiko Matsushita, “Redox reaction by thermal excitation carriers in semiconductors: semiconductor-sensitized thermal cell,” Chem. Commun., 2025,61, 5556-5562.
https://doi.org/10.1039/D4CC06325B


Sachiko Matsushita, “Redox Reaction by Thermally Excited Carriers in Semiconductors: Semiconductor-Sensitized Thermal Cell,” Denki Kagaku (The Electrochemical Society of Japan), 2024, Vol. 92, Issue 3, pp. 235–239.
https://doi.org/10.5796/denkikagaku.24-FE0305
Video Overview (YouTube): https://www.youtube.com/@elleThermo

Further Notes:
*All company names, product names, and logos included in this news release are the trade names, trademarks, or registered trademarks of their respective companies.
*The information in this news release is valid as of the date of announcement. Service and product fees, service content and specifications, and other information may be subject to change without notice.