Most BESS failures due to sub-standard assembly and construction

More than a third of BESS failures due to faulty construction, with the integration of ‘incompatible components’ a common mistake


May 24, 2024

  • 36% of BESS failures due to faulty integration, assembly and construction, EPRI report concludes
  • Integrating ‘incompatible components’ is common mistake
  • BESS failures could be mitigated by better workforce training and quality checks

Most battery energy storage system (BESS) failures, including fire incidents, occur as a result of faulty integration, assembly and construction work, according to a new report by the US-based Electric Power Research Institute (EPRI).

The report concluded that sub-standard integration, assembly and construction work was the root cause in more than a third (36 per cent) of BESS failures. By comparison, only 29 per cent of failures were attributable to the operation phase of the BESS. Meanwhile 21 per cent of failures were due to BESS design, and just 4 per cent were attributable to the manufacturing process.

Source: EPRI

Integrating incompatible components is common mistake

In the integration, assembly and construction phase of BESS projects, a common mistake is integrating components that are incompatible. The vast majority of BESS failures attributable to integration involved ‘balance of system’ (BOS) components – which include DC and AC wiring – HVAC [heating, ventilation and air conditioning] subsystems, and safety elements such as fire suppression systems. The EPRI report warned that lithium-ion BESS “contain components from multiple suppliers, which are not necessarily designed to work together”. It added that integration is a “critical part of the deployment and installation process to ensure all interfaces are compatible and functional”.

The report highlighted the 2021 incident in Australia at the Victoria Big Battery facility as an example of BOS failure due to assembly quality issues. During commissioning, a leak in the coolant system led to a fire that spread across two BESS units. A report on the fire by Fisher Engineering, Inc and the Energy Safety Response Group recommended that, to prevent such incidents, there should be “improved inspection of the coolant system for leaks during Megapack assembly and during end-of-line testing to reduce the likelihood of future coolant leaks”. It was also recommended that there should be “active monitoring and control of the pyro disconnect’s power supply circuit”.

In order to mitigate failures and fire risks associated with the integration, assembly and construction of BESS, the EPRI report made the following recommendations:

  • Ensure there is effective workforce training and quality checks during the energy storage commissioning and installation process
  • Conduct system-level failure analysis, especially for interfaces between components.

Less stringent quality control in integration phase

A report published in February this year by Clean Energy Associates, entitled ‘BESS Quality Risks’, concluded that the BESS integration process is “highly manual and labour intensive, with less stringent quality control procedures”. The report also concluded that 26 per cent of BESS units had defects in the fire suppression systems, while 18 per cent of units had thermal management system defects.

The EPRI report said that, while recent fires afflicting BESS had “garnered significant media attention”, the overall rate of incidents has sharply decreased because lessons learned from early failure incidents have been incorporated into new designs and best practices. The global installed capacity of utility-scale BESS has dramatically increased over the last five years, with the result that the BESS failure rate has actually dropped 97 per cent (see chart below).

Storage fire incidents can cost up to $2 million

Battery storage fire incidents can cost developers, owners or operators up to $2 million as a result of the catastrophic loss of an asset and loss of revenue from up to 18 months’ worth of downtime, fire suppression system supplier Firetrace International said earlier this year. Firetrace said another cost battery owner-operators have to deal with is the expense incurred due to false activations, which, the company claimed, is an increasing issue in the sector. False activation costs can reach as high as $900,000 when clean-up expenses and resulting downtime is taken into account.

South Korea and the US are the countries that have suffered the largest number of utility scale or industrial energy storage-related fires, data from EPRI shows. The EPRI database reveals that, from 21 September 2011 to 27 July 2023, there were a total of 63 “utility and commercial & industrial-scale energy storage failure events”. Just under half of the events (31 in total) were located in South Korea, meaning the East Asian country has experienced the most major incidents during the 12-year period. Meanwhile, a report published last year by Firetrace concluded that there is a real danger public opposition to energy storage could grow significantly as a result of fire risk fears, threatening critical battery deployment and, as a result, net zero goals.