Fire risks at biomass power plants and the latest monitoring technology

Proposal for safety measures and monitoring system for biomass power plants

Article updated: 2025.3.13

Introduction

Biomass power generation is attracting attention as a key source of clean energy. However, did you know that it also poses a major fire risk?

The number of biomass power plants in Japan is on the rise, and expectations for replay energy are also rising. However, wood biomass fuel comes with invisible risks.

As experts are actively discussing this issue, the Ministry of Economy, Trade and Industry issued a groundbreaking notice on February 1, 2024. The notice is titled "Request for thorough safety measures at biomass power plants and reporting of accidents."

This article introduces the actual fire risks at power plants and an innovative monitoring system aimed at reducing those risks.

For details, click here (Ministry of Economy, Trade and Industry)

Request for safety assurance and accident reporting at biomass power plants

In response to the recent spate of fires and explosions at storage and transportation facilities for biomass fuels, this notice calls for the following three measures:

1. Safety measures tailored to fuel characteristic

Since the quality of fuel varies depending on the place of production, it is necessary to take appropriate safety measures according to characteristic of each fuel. In particular, we conduct thorough patrols, inspections, and cleaning of facilities where accidents have occurred in the past.

2. Prompt reporting of accidents

In the event of a fire or other accident, even if it is not required by law to be reported, we will promptly report it to the relevant Industrial Safety and Health Supervision Department. This is to promote early response and information sharing.

3. Preventing recurrence through information sharing

After reporting, we will investigate the cause and share measures to prevent recurrence through industry associations in an effort to prevent similar accidents from occurring.

This notice is intended to call on each operator to strengthen safety measures and promptly share accident information, in order to maintain social trust as well as comply with legal obligations.

Biomass fuel ignition risk and accident examples

Why does it ignite?

Wood pellets and wood chips pose a fire risk due to microbial fermentation, oxidation, and heat accumulation.

Heat generation mechanism

Heat is generated by internal fermentation and oxidation
As heat accumulation progresses, the risk of spontaneous combustion increases.

Explosion risk factors

Accumulation of flammable gases (e.g. methane, carbon monoxide)
Dust explosion caused by wood dust
Static electricity and heat from friction can cause ignition

Actual accident cases

Below are some examples of accidents that have occurred in Japan and around the world.

Accident Number	Location of occurrence/Plant name	Year of occurrence	Cause of the accident	Time from outbreak to extinguishing	Estimated damage amount	Current situation
1	Chiba Sodegaura Biomass Power Plant	2023年	Ignition due to spontaneous heating of wood pellets	Approximately 4 months (fire broke out on January 1, 2023, and was confirmed to have been extinguished on May 1 of the same year)	Not published	Fuel removal completed, measures to prevent recurrence implemented
2	Kyoto/Kansai Electric Power Maizuru Power Plant	2023年	Heat generation due to fermentation and oxidation, accumulation of flammable gases, spontaneous combustion	The exact time the fire was put out is unknown.	Not published	Fuel management methods reviewed, monitoring equipment added
3	Tottori Yonago Biomass Power Plant	2023年	Possibility of flammable gas generation and dust explosion due to natural fermentation of wood pellets	Approximately 3 hours and 50 minutes (fire broke out at 9:22 on September 9, 2023, and was extinguished at 1:15 p.m.)	Not published	Measures to prevent recurrence are currently under consideration.
4	Aichi JERA Taketoyo Thermal Power Plant	2024年	Dust explosion caused by pulverization of wood pellets and frictional heat	Approximately 5 hours (fire broke out at 15:11 on January 31, 2024, and was extinguished at 20:04)	Not published	Measures to prevent recurrence are being implemented
5	Case study: Texas, USA	2017年	Fire caused by spontaneous heating of wood pellets	The exact time the fire was put out is unknown.	Not published	No information
6	Yamagata / Yamagata Biomass Energy Power Plant	2019年	Explosion of a hydrogen gas tank (insufficient performance of backfire prevention device)	Instant explosion, time to extinguish fire unknown	Not published	After the accident, the design and construction company began bankruptcy proceedings

Functional requirements for a surveillance system

To deal with the risk of fire, it is important to monitor the condition of fuel and equipment in real time and detect abnormalities early. Conventional fire alarms only sound an alarm after detecting smoke or flames, so a mechanism is needed to detect temperature increases in advance.

①

Continuous Temperature Monitoring

The temperature of fuel storage facilities and transportation facilities is monitored in real time 24 hours a day.

②

Early anomaly detection

It detects abnormal heat before smoke or flames appear, enabling rapid initial response.

③

Alerts and notifications

Automatic alarm when the set temperature is exceeded. Immediate notification is given via on-site buzzer, control room display, email and SMS.

④

Remote and Integrated Monitoring

Temperature data from multiple locations can be centrally managed and remote operation is also possible. It will also support centralized monitoring between plants in the future.

⑤

Recording and Analysis

Accumulate temperature data and use it for trend analysis and report creation. Use it as reference for predictive maintenance and inspection planning.

Proposed solution

The proposed solution is a non-contact heat detection system that uses high-performance thermal imaging cameras. Fixed cameras are installed at key points within the power plant and managed with dedicated monitoring software, enabling rapid detection and response to abnormalities.

High-performance thermal imaging camera "CPA-L3"

High-resolution cameras are installed at key points. Thermography with a resolution of 640 x 480 pixels and a temperature accuracy of about ±2°C ensures that even small abnormalities are detected.

By overlaying thermal images and visible light images, it is possible to simultaneously grasp temperature abnormalities and on-site conditions.

Click here for more information on CPA-L3

Integrated monitoring software "CISAS"

It is an integrated platform that centrally manages data from various sensors and measuring devices, and is equipped with a wide range of functions such as threshold monitoring, alarm notifications, and remote viewing.

Real-time temperature values and heat map images allow you to immediately identify abnormalities.

For more information about CISAS, click here

Dual monitoring with composite sensor "Silo temperature measuring cable"

In addition to thermal images, a temperature cable sensor is installed inside the silo to detect abnormalities from both the inside and outside, improving reliability.

Click here for information on silo temperature measuring cables

Flexible alarm settings

You can set alarm levels such as "Caution," "Warning," and "Emergency." When an alarm occurs, the thermal image is automatically saved and can be used for later analyzing.

system configuration diagram

The entire process of temperature detection, alarm, recording, and notification is automated. Data acquired by the thermal imaging camera is sent to the monitoring PC via the network and display in real time on CISAS.

Alert Levels and Response Flow

Alert Level	Example Conditions	Notification Method	Examples of support
Note	Fuel surface temperature exceeds 50°C	Pop-up display on the person in charge's PC	Strengthening surveillance and checking the situation
caveat	Fuel surface temperature exceeds 70°C	Email notifications to field workers and managers	Fuel mixing and cooling in the relevant section
emergency	Fuel surface temperature exceeds 90°C	Global emergency bell activation, SMS notification	Fuel removal, fire notification

Preventive maintenance using data

CISAS accumulates temperature data as logs and enables trend analysis and report generation, allowing you to understand temperature rise trends in specific silos and use this information to make decisions about routine inspections and planned shutdowns.

In addition, by linking with visible light camera footage, it is possible to simultaneously record the on-site situation when temperature abnormalities occur. In the case of a dust explosion, the footage immediately prior to the occurrence can be useful in identifying the cause.