A lithium-ion battery in a container near Phoenix owned by Arizona Public Service (APS) caught fire in April 2019, then other batteries in the container caught fire, releasing explosive gas and sparking an explosion that hurt several first responders.
Such battery fires, prompted by high temperatures resulting from mechanical failure, damage to the batteries or short circuiting, have spurred new standards to ensure energy storage isn’t subject to this thermal runaway, says Wes Kennedy, instructor of HeatSpring’s Comprehensive Solar Plus Storage course.
While these emerging local, state and federal standards and guidelines aim to provide for safe energy storage, they add unnecessary time and costs when they focus on battery chemistries that don’t spark thermal runaway and fires, Kennedy says.
Standards Assume Risk of Thermal Runaway for All Battery Chemistries
“In most of these standards, all these different chemistries of lithium batteries are treated the same. It doesn’t matter what the sub chemistry is; the standards assume a risk of thermal runaway,” he says.
But one chemistry, iron ferrous phosphate, is not subject to thermal runaway. It’s time-consuming and expensive for iron ferrous phosphate battery providers to meet the unnecessary standards. For example, installers can spend up to $100,000 extra installing energy storage systems in containers to ensure safety.
“There’s a growing push for these codes and standards to differentiate down to the chemistry level,” says Kennedy.
A Hierarchy of Standards
The regulations and guidelines created over the last year or so are a “nested hierarchy of standards” that begin with individual battery cells that must meet Underwriters Laboratories (UL) standards. As more components are added, more standards come into play.
For example, not only do UL standards affect single battery cells; they require safety measures when the battery is bundled into a system that might include an inverter or controller.
In general, standards and regulations call for fire extinguishers and ventilation systems. Doors leading in and out of a space containing storage need to have safety bars, said Kennedy.
New Systems-Level NFPA Standards Aim to be Comprehensive
To avoid these overlapping regulations, the National Fire Protection Association (NFPA) recently released new systems-level standards, NFPA 855, that aim to create a more comprehensive set of standards. For example, the standards, which are not enforceable but aim to provide some guidance, say that energy storage systems should not create toxic gas beyond a given limit.
“The NFPA standards are in place technically, but not being enforced virtually anywhere,” says Kennedy. They are, however, now part of the International Building Code and it will be up to local jurisdictions to decide whether to adopt them.
Additional Standards from California
Meanwhile, the state of California, home to the largest energy storage market in the country, has issued residential building-level standards for energy storage.
“It’s all overlapping and everyone is trying to understand how it will all shake out,” says Kennedy. For installers, integrators and others, a first foray into integrating energy storage, whether residential or commercial, can feel like a big hassle.
It’s important for storage providers and integrators to figure out what local jurisdictions require and understand that the next county may have a different set of requirements.
“There’s a very disjointed and broken level of enforcement,” says Kennedy.
Work Needed to Allow Standards to Be Helpful
There’s still work needed to ensure these well-meaning regulations and guidelines achieve their goal of making energy storage safe. An enforceable overarching standard such as NFPA 855 would be helpful. And standards should focus only on chemistries that are subject to thermal runaway, he adds.
“The different chemistries should not be treated the same from a code perspective,” says Kennedy.
Comprehensive Solar Plus Storage Updated and Beginning
Come join Wes in a brand new and fully updated version of his Comprehensive Solar Plus Storage course which begins next week!