The safety of energy storage systems is under scrutiny after firefighters were injured in an Arizona battery plant explosion in April, and it emerged that at least 23 South Korean plants caught fire in a series of incidents dating back to August 2017.

For now, many experts continue to stand behind energy storage's track record on safety in the context of the broader power market.

When testing energy storage technologies, safety is not viewed as part of a hierarchy of requirements, but is “a simple pass-fail,” said David Kane, technology development manager at the energy company Centrica in the U.K.

“If we cannot be satisfied that the system is safe, then we just can’t pass go,” he said. “That doesn’t just apply to the final product design. It applies to the installation, the service, the decommissioning [and] the various steps in the supply chain.”

Arizona Public Service (APS) still has not revealed the cause of a blast that the Associated Press last month claimed had “sent eight firefighters and a police officer to the hospital.”

However, as previously noted by GTM, the utility has one of the most aggressive energy storage adoption strategies in the U.S., with plans to install roughly a gigawatt of battery capacity by 2025.

Pressures associated with a hasty build-out of battery capacity appear to have been the cause of numerous lithium-ion facility fires in South Korea.

Last month, S&P Global reported that a five-month investigation into the blazes had put the blame on faulty installations and poor operating procedures rather than the batteries themselves.

How the industry responds is critical

Analysts at Wood Mackenzie predict enormous growth for the global storage industry in the years ahead, reaching 600 gigawatts of stationary storage by 2040, up from about 4 gigawatts today.

But the recent safety incidents are problematic for the lithium-ion battery industry, which even this month was being linked to a fire aboard a Virgin Atlantic flight.

For lithium-ion battery makers, said Rory McCarthy, senior research analyst at Wood Mackenzie Power & Renewables, “safety has always been a concern. There’s a very well-known risk of thermal runaway.”

Events in South Korea and Arizona have once again highlighted the safety issues associated with lithium-ion batteries. Now, “more has to be done to give assurances to everyone involved that these are being handled effectively,” McCarthy said.

Because energy storage is still relatively early in its technological maturation, observers believe incidents are to be expected. Whether this might affect the growth of the industry will depend on the industry’s response to these safety incidents, McCarthy said.

“If lessons aren’t learned and the correct controls and measures are not put in place then it could hinder [growth],” he said.

This applies to emerging energy storage technologies such as hydrogen as much as it does to lithium-ion batteries. The nascent hydrogen fuel-cell vehicle sector took a knock last month when a Norwegian filling station exploded.

Operator Nel Hydrogen leaped into crisis mode and published regular updates about the accident, which was ultimately pinned on an assembly error of a plug that led to a hydrogen leak.

Michela Bortolotti, communications manager at the industry body Hydrogen Europe, said the sector would be looking to learn from the incident. In theory, though, hydrogen should pose no more of a threat than gasoline, diesel or natural gas, she said.

“When handled correctly, hydrogen is just as safe as other fuels, but less toxic, and an indispensable component in achieving our climate goals,” Bortolotti said. “Now the hydrogen sector needs to work even harder on its already high safety standards.”

Even a few is "too many"

Other experts have highlighted the fact that, compared to the wider power sector, energy storage has a relatively good safety record.

The dangers of electrical equipment generally were highlighted at APS this month when the utility lost an employee to an underground fire during routine network maintenance work.

Against this already hazardous backdrop, energy storage technology and project developers must tread carefully.

“Any indications that fires are not limited to individual companies or individual markets gives people pause,” said Logan Goldie-Scot, head of energy storage at Bloomberg New Energy Finance.

So far, “we are still talking about a relatively small proportion of impacted capacity, most of which was concentrated in a single market,” he said. “But even a few projects is too many.”

Bernardo Orvananos, technology, strategy and innovation manager at Centrica Business Solutions, said the number of incidents seen in South Korea was “not normal and not something we should be comfortable with.”

“I think there are a lot of lessons to be learned over there that can be transferred to other markets,” he said. “Hopefully this high fraction of incidents will not happen elsewhere.”