An energy storage system (ESS) stores electricity generated by solar and wind power and supplies it when needed. Although it is essential for expanding renewable energy and stabilizing electricity supply, the concentration of large numbers of batteries means that a fire can cause extensive damage.
ESS fires are not a new problem. In South Korea, a series of battery fires since 2017 has prompted industry and the government to introduce safety measures on several occasions. Even so, incidents have not been eliminated.
On June 16, 2025, a fire broke out in an ESS electrical room in Pohang, North Gyeongsang Province. Following the incident, the Gangwon State Fire Headquarters launched emergency safety inspections of battery manufacturing plants and ESS facilities in the province. The case showed that ESS facilities are not simply electrical installations but high-risk facilities requiring consideration of both fire prevention and response.
What are the risks at electricity storage facilities?
An ESS combines batteries, power conversion equipment and control systems. It stores electricity generated by solar power during the day for use at night, or supplies stored electricity when demand surges. It is also used to maintain power grid stability.
The problem is the concentration of high-capacity batteries at these facilities. If abnormal heating occurs in one battery cell, heat can transfer to neighboring cells and develop into a chain reaction of thermal runaway. The possibility of fire spreading must be considered in an ESS, where batteries are connected across multiple modules and racks.
The results of an ESS fire investigation released by the Ministry of Trade, Industry and Energy in 2019 stated that 14 of the 23 incidents examined occurred while systems were on standby after charging. This means that completing a charge does not guarantee safety.
The investigation committee identified major causes including inadequate protection against electrical disturbances, insufficient management of operating environments, careless installation, and inadequate integrated control and protection systems. Manufacturing defects were also found in some battery cells, but demonstration tests simulating those defects did not reproduce a fire. The findings showed that ESS fires are difficult to explain solely as a problem with the batteries themselves.
What must come before firefighting
Detecting warning signs before an incident occurs is important in responding to ESS fire risks. A battery management system (BMS) monitors conditions such as cell voltage and temperature and detects abnormalities. Facilities also need a system that continuously records operating data and identifies abnormal temperature increases or voltage changes at an early stage.
However, installing a monitoring system does not mean every incident can be prevented. Checks must also establish whether sensors properly detect abnormalities, whether operation actually stops when an alarm sounds, and whether managers can respond promptly.
The government's additional safety measures in 2019 included state-of-charge management, retention of operating records and support for moving indoor installations outdoors. These measures reflected the judgment that facilities need operating systems that not only manage battery condition but also allow incident causes to be traced and damage to be reduced.
Even firefighters face difficulties approaching the site
ESS fires also create difficulties for fire crews. Facilities contain high-voltage electrical equipment, and thermal runaway in batteries creates a risk of reignition. Before approaching a fire, crews must check whether power has been disconnected, the equipment layout and the condition of the batteries.
Even when flames have disappeared, safety cannot be assumed without checking that internal temperatures have fallen sufficiently.
This is because heat remaining inside a battery can transfer to neighboring cells and cause reignition. ESS facilities therefore need fire suppression equipment, detection devices, fire compartments, ventilation and smoke extraction, and emergency shutdown systems designed around characteristics that differ from those of ordinary buildings.
Information must also be shared so that responding fire crews can identify battery types and layouts and the locations of disconnect devices in advance.
Safety also matters as renewable energy expands
ESS is a technology needed for renewable energy expansion and power grid stabilization. Reducing its use simply because it poses a fire risk is not the answer. What matters is managing risks throughout manufacturing, installation and operation, and preparing to prevent damage from spreading even if an incident occurs.
Improving battery quality alone is not enough. Installation conditions, state of charge, temperature management, control systems, regular inspections and fire response must work together. Retaining operating records is also important so that the cause of an incident can be accurately established.
Electricity storage technology is an important component of future energy systems. However, failure to control the stored energy safely could hinder the energy transition.
The competitiveness of ESS depends not only on how much electricity it can store but also on how safely it can store and supply that electricity.
Original Korean article: kdsn.co.kr
English brief by Korea Wind Intelligence, koreawindintel.com
