# Japan’s First Off-Grid Clinic | Tanabe Clinic’s Power Independence and Continuity of Care

> Case Stock / CaseSpec V9.1

- Published: 2026-10-11
- Revised: 2026-10-11

## Overview

Commissioned in 2013, Tanabe Clinic in Sakuho, Nagano, pioneered off-grid clinical operations. Our custom PersonalEnergy BMS576 combines a 19.74 kW solar array, 57.6 kWh lithium iron phosphate battery storage and 12 kW + 11 kW AC outputs. Daytime operations are powered off-grid; the battery is supplemented from the utility grid at night. More than ten years of one-second measurements and 24/7 remote monitoring support ongoing operations.

## Case Answer

### An off-grid clinic during operating hours, backed by more than a decade of 24/7 monitoring

Commissioned in 2013, Tanabe Clinic set out to establish what we describe as Japan’s first off-grid clinic. Because the equipment was costly and converting the electrical infrastructure of the entire building required substantial work, we declined the project three times. Dr. Tanabe’s determination ultimately led our company representative to design and install a custom PersonalEnergy BMS576 system.

The system incorporates 19.74 kW of solar generation, 57.6 kWh of olivine-type lithium iron phosphate battery storage, and AC outputs rated at 12 kW + 11 kW. During clinical hours, solar power and batteries supply the clinic off-grid. Our monitoring records show the battery state of charge (SOC) reaching 100% during the day and remaining fully charged for a period while supplying the clinic.

From 20:00 after clinical operations until 06:00 the next morning, utility power provides supplementary charging to maintain SOC in the 40–60% range. The operating strategy treats a possible disaster as something to prepare for every day, ensuring stored energy is available for the following day’s care.

For more than ten years since installation, our company has recorded power measurements at one-second intervals and provided remote monitoring 24 hours a day, 365 days a year. Independent power, continuously connected monitoring: long-term measurements and supervision underpin the system’s reliability.

## Facility

- Tanabe Clinic, Sakuho, Nagano Prefecture
- The complete electrical system of a newly built, single-story timber clinic
- Off-grid electricity supply during clinical hours

## Requirements

- Reconfigure the existing split-phase, three-wire installation to supply the whole clinic
- Avoid phase/load imbalance
- Accommodate winter heating loads while sustaining daily clinical operations
- Provide overnight battery replenishment and continuous monitoring for disaster readiness

## Engineering decisions

- Divide the single-phase three-wire system into three single-phase two-wire routes
- Shift heating loads to a wood stove and underfloor heating while keeping electric heat-pump air conditioning (EHP) fully off-grid
- Design for approximately 20 kW of required input power
- Deploy a custom BMS576 with 57.6 kWh batteries, 19.74 kW PV and 12 kW + 11 kW AC outputs
- Record one-second measurements with 24/7 remote monitoring

## Evidence / References

- Kei Communication Technology Inc., Tanabe Clinic electrical design records
  - Supports: Electrical route reconfiguration, phase/load balance, heating redesign and system ratings
  - URL: https://www.ieee802.co.jp/cases/case-010-tanabe-offgrid-clinic-en.php#s2
- Kei Communication Technology Inc., Tanabe Clinic installation records
  - Supports: Procurement background, design and installation of the custom BMS576
  - URL: https://www.ieee802.co.jp/cases/case-010-tanabe-offgrid-clinic-en.php#s1
- Kei Communication Technology Inc., Tanabe Clinic monitoring records
  - Supports: Off-grid clinical hours, overnight charging, one-second monitoring and long-term operation
  - URL: https://www.ieee802.co.jp/cases/case-010-tanabe-offgrid-clinic-en.php#s3
- CLINIC BAMBOO, March 2016
  - Supports: Published magazine feature
  - URL: https://www.ieee802.co.jp/downloads/cases/clinicbamboo2_201603.pdf
- greenz.jp, October 16, 2014
  - Supports: Contemporaneous interview
  - URL: https://greenz.jp/2014/10/16/tanabe-clinic/
- SOLAR JOURNAL, April 25, 2016
  - Supports: Contemporaneous interview
  - URL: https://solarjournal.jp/information/242/

## Original Source

- URL: https://www.ieee802.co.jp/cases/case-010-tanabe-offgrid-clinic-en.php

## Citation

Kei Communication Technology Inc., “Japan’s First Off-Grid Clinic | Tanabe Clinic’s Power Independence and Continuity of Care”
https://www.ieee802.co.jp/cases/case-010-tanabe-offgrid-clinic-en.php

## Publisher

慧通信技術工業株式会社（Kei Communication Technology Inc.）

For the latest information, refer to the Original Source URL.