Lithium-ion batteries tend to overheat.  When these batteries overheat, they spontaneously combust causing fires that cannot be put out.  Yet, large solar farms have large battery storage stations containing hundreds of large container-sized lithium-ion batteries close to each other.

What have governments and solar farms done to mitigate or deal with this catastrophic disaster in waiting?  If the US solar farms are anything to go by – nothing.

“The growing threat of grid-scale battery fires is a very serious issue calling for equally serious action,” Dr. David Wojick writes.

Related: London’s spontaneous bus combustion: How is this being allowed to happen? and Norwegian Shipping Company bans electric vehicles on its vessels

Grid-scale battery fires loom large

By Dr. David Wojick

America faces a growing threat from grid-scale lithium battery fires. Construction of huge battery arrays with no concern for potentially catastrophic fires is out of control. There are no established standards to follow and local permitting authorities seem oblivious to this very real danger.

What follows is a brief introduction to the issue. To begin with look at this photo of an existing grid battery array called Desert Sunlight: 

The batteries are teamed with a big solar facility because until recently that was the only way to get battery subsidies. Each lithium battery unit is the size of a tractor trailer or big shipping container and there are well over a hundred of them, with a rated storage capacity of 230 MW. This is a medium-sized storage facility.

That these units can spontaneously burst into flames is well established. The question is how to design and prepare for this destructive event.

To scale the problem, consider the following event. A battery-powered tractor-trailer rig recently crashed and its battery burned on an interstate in California. Lithium battery fires cannot be put out so this one burned for around eleven hours. To keep the fire from spreading to create a wildfire the fire crew continuously sprayed it using a reported 50,000 gallons of water in the process. The interstate was closed due to the toxic fumes from the fire.

One of these grid-scale battery units is easily 10 to 20 times the size of that truck battery. If the water usage required to keep a grid battery fire from spreading scales with size that is 500,000 to a million gallons of water. The actual amount is an engineering calculation that needs to be established and incorporated into battery facility design standards.

Note that we are not talking about the fire spreading to create a wildfire although that is certainly a concern. The vital need is to keep it from igniting the nearby batteries. If this happened the whole facility could go up with a hundred or more giant batteries burning. That would be truly catastrophic.

So now look at the Desert Sunlight photo and note there is no water tank. There should be something like a million-gallon water tank with a high-volume system to deliver that water to every unit in the facility. Clearly, there is not.

There is also the engineering question of how far apart these units should be to enable that water to work keeping the fire from spreading. I doubt the Desert Sunlight spacing is even close to big enough. It looks like just room to walk between them.

Now let’s turn to permitting these facilities where I have another example that speaks volumes. This is a facility that just got permitted by Washington State. It is a combined wind, solar and battery project with a proposed storage capacity of 300 MW, which is considerably bigger than Desert Sunlight. It might have 200 huge lithium battery units. That number is not disclosed.

The project is named the Horse Heaven Wind Farm despite its massive solar and battery components. The name, usually shortened to Horse Heaven, is truly ironic because it will be no place for horses. Horse Hell might be better.

The permitting authority is the Washington Energy Facility Site Evaluation Council or EFSEC for short. The permit is called a Site Certification Agreement or CSA and Horse Heaven just got one, with a big push from the Governor.

The astounding point is that there was no discussion, or even recognition, of the fire threat posed by this enormous lithium battery facility. The CSA has numerous requirements for lots of issues, big and small, right down to the facility having water to keep the road dust down. There is nothing on having a million or so gallons to prevent a catastrophic conflagration, nor on the environmental impact of such.

This is wildfire country so there should be liability insurance for harm to others from a fire. Other potential sources of harm are huge amounts of contaminated water runoff as well as toxic air emissions, especially if the whole facility burns.

This neglect no doubt flows from the Horse Heaven application. The application is over 500 pages long and I can find just one sentence about battery fires. Buried in a long paragraph on PDF page 366 we read: “Lithium-ion battery storage may pose a risk of fire and explosion due to the tendency for lithium-ion batteries to overheat.”

This single sentence does not even refer to the project. For that matter, there are only a few paragraphs about the battery facility in the entire application, mostly just describing it in general terms. There is nothing about the number of giant battery containers or that it is a huge project in its own right, posing an equally huge fire threat. In fact, the application says they might double-deck these container-sized battery units which is absurd given the risk of setting off a chain reaction in the whole complex.

One can easily think from the application that the batteries are of no significance and that appears to be exactly what has happened at the EFSEC.

This systematic neglect looks to be what is happening around the country. We desperately need a national code or standard covering this issue. The National Fire Protection Association says it is working on one, but it is up to the permitting authorities to make something happen.

The growing threat of grid-scale battery fires is a very serious issue calling for equally serious action.

About the Author

David Wojick, PhD, is an independent policy analyst and senior advisor to CFACT. As a civil engineer with a Ph.D. in logic and analytic philosophy of science, he brings a unique perspective to complex policy issues. His specializes in science and technology intensive issues, especially in energy and environment. As a cognitive scientist he also does basic research on the structure and dynamics of complex issues and reasoning.

Featured image taken from ‘How Solar Farm Fires Can Damage the Environment’, Fire Trace International, 11 October 2022