As energy storage systems (ESS) evolve and as NFPA considers a new standard for ESS safety, research continues in an effort to improve the materials, design, and methodologies that underlie this rapidly expanding technology
INTERVIEW CONDUCTED BY JESSE ROMAN
A FEW YEARS AGO, as researcher David Rosewater tested a large prototype battery system at his lab at Sandia National Laboratories in Albuquerque, New Mexico, smoke started to billow from one of the components. Soon, small flames were shooting up from the system, the result, Rosewater discovered later, of an undersized and overloaded resistor that had sparked and ignited one of the battery’s subsystems. The fire was quickly extinguished and no one was hurt, but the episode “made me question what the state of the art knew about preventing incidents in these systems and led me down a path of research into battery system safety as an engineering discipline,” Rosewater said in a recent interview with NFPA Journal.
While millions of batteries operate every day without incident, recent episodes of burning or exploding mobile tablets, hover boards, e-cigarettes, and cellphones illustrate the batteries’ destructive potential. If something similar were to occur on a larger scale—say, in a tractor-trailer-sized battery system connected to an energy grid—it could pose a danger to first responders and the public in the form of fire, explosion, toxic fumes and chemicals, and electrical arcing.
At Sandia and other research facilities, such as the Pacific Northwest National Laboratory (PNNL), researchers are working to develop better designs, better materials, and better technologies to reduce the risk of battery disasters. NFPA is also working toward that goal by developing better regulations surrounding battery systems, also known as energy storage systems (ESS) in industry parlance. This year, NFPA formed an ESS technical committee, comprising researchers, manufacturers, first responders, and others, to develop a new comprehensive ESS standard that committee members hope will bring consistency to ESS design, installation, and emergency response.
As the industry expands rapidly across the world, additional clear rules and guidance are needed, said Rosewater, who is one of 30 members on NFPA’s newly established ESS technical committee. While installations were scant just five years ago, today thousands of battery systems are being installed each year in residential homes, businesses, office parks, and utility power stations. The accelerated adoption of ESS is due to the myriad economic and environmental advantages batteries offer, including “peak shaving,” the practice of storing energy in batteries when prices are low and using that power during expensive times; greater energy independence; more efficient use of renewable energy; backup power in emergencies; and enabling utilities to better manage energy usage on the electrical grid. Technological advancements have also helped.
To meet demand, next year Tesla plans to open a $5 billion battery manufacturing plant in the Nevada desert called the Gigafactory, which will churn out batteries at a volume once thought unimaginable. A gaggle of other companies such as LG Chem, GE, and Siemens are also investing heavily in ESS, while researchers in both the public and private sectors are constantly working to perfect new designs and chemistries.
Many researchers, including Rosewater, are working to try to make ESS safer. Numerous projects are ongoing at Sandia and PNNL, including efforts to develop safer battery materials and to design better fire suppression systems and suppressants for batteries. At Sandia, an entire lab is devoted to conducting abuse tests to find out how batteries respond under abnormal conditions—shock, external damage, fire, overheating, overcharging, and more.
NFPA Journal spoke with Rosewater about the state of battery safety research, his aspirations for NFPA’s new ESS technical committee, and what hazards batteries could pose for first responders, installers, and the public.
For a number of reasons, ESS installations are increasing very rapidly. How fast is the technology evolving?
New technology is coming out every year. There is research going on at the national labs, in academia, and in the industry to push the envelope, and it is changing very rapidly.
Even in the five years that I’ve been in this field, I’ve seen the industry grow exponentially. At the national laboratories, we’re helping to drive that through the development of better technology, and there is a strong push from industry to help solve energy problems within the grid and to go after new markets. This dynamic has developed a pipeline for rapid deployment of these battery technologies that are going from bench-top scale to system installation in just a few short years. On one hand, this is a great development for the world’s transition to sustainable energy, but it also brings with it challenges to ensure that these new technologies are deployed safely. It’s a challenge, but not an insurmountable one.
Is the innovation creating concern? Are new hazards developing faster than you can control them?
From our perspective, generally no. Safety is actually generally improving across the board. We’re understanding more about the mechanisms of safety every year. Also, standardization of both safe designs and safe processes ensures that the new technologies that are coming out are actually held to an ever-rising bar for safety. New issues will continue to come up, there may be fires in battery systems that continue to make headlines, but we should temper this hype with the understanding and knowledge that thousands of systems are operating quietly, incident free every single day. And this process is, of course, part and parcel with the deployment of just about every new technology. Every new technology follows this course.
What challenges and hazards do big batteries present to the public and first responders?
All batteries have three main hazards: voltage, arc flash blast, and fire. These hazards are already well understood and controlled in the built environment. None of these hazards is new or unique to batteries, and safety engineering methods are already available to control and adequately reduce risk in the event of an accident or incident in these systems.
Specific battery types, such as lithium ion or lead acid batteries, have their own additional specific hazards, such as vent gas combustibility or toxicity. But so far I haven’t seen any hazards in battery systems that aren’t already well understood in other built environments, whether it is chemical processing, the power industry, or somewhere else. These are hazards that are well understood, and we just need to control them through design.
How do you do that?
A good design will consider all the interactions between system components in every possible configuration. It enforces system safety constraints with redundancy and error checking. That’s a really tough thing to do, but it’s getting easier as the technology and knowledge base progresses.
What is the hardest part of designing safety into these systems?
One of the toughest parts of designing safe systems is that humans are a part of any technical system that they are working with. Humans don’t exactly behave in cleanly predictable ways. Whenever people interact with these systems, the methods for safety engineering need to adapt to that new medium, that new mode. This is one of the things that really make NFPA’s work in energy storage so valuable. Developing guidance on first responder tactics, risk assessment standards, that whole breadth of research that NFPA is doing for the fire service to respond to these incidents in battery systems is, in effect, engineering safety into interactions between the firefighters and the systems, and that is critical. We rely on the fire service to protect the life and safety if anything goes wrong in these systems, and they need the tools and procedures to stay safe in that work.
What are some ESS issues that the new NFPA technical committee might tackle?
I think the goal of the committee is to develop new standards for the installation of energy storage on the grid that will provide clear instructions to manufacturers, building owners, first responders, and others for the safe design of ESS that considers both how the fire service interacts with the technology and any other design considerations related to installing the systems.
What would that include?
It would include aspects such as sighting, signage, warning labels, as well as safety lighting, clearances, all of these things. A lot of it you can get a handle on through the design process, but it will be much easier for everyone involved if we can provide those kinds of requirements in a clear standard that installers and manufactures can point to and say, “Yes, we did it right.” A successful standard will protect life and property if something goes wrong, but it will also streamline the process and bolster the industry.
Does any guidance like this exist already?
The guidance is out there and there are safety engineering practices that can prevent any of the hazards that batteries present, but putting it all in one place and resolving conflicts, such as what specific abusive conditions batteries must be tested under, will be one of the hardest and most important things this committee is going to do.
Where and how are these batteries used?
You see them popping up everywhere, at any point of connection to the grid that you can imagine. It is everything from a residential scale to large-scale storage at the transmission level.
Energy storage has been especially useful for utilities. Historically, the grid has been operated as a product distribution system with no buffer. Imagine trying to run a seafood distribution system with no warehouses, or a water distribution system with no tanks. It’s been hard to deal with that, matching load and supply every moment of every day, and it is getting harder because there are more variable sources being introduced into the grid. This is a challenge, but it is an engineering problem that can be solved, and one thing that can help solve it is storage. So we are really moving to this as a natural product of our move toward a more sustainable energy economy.
There’s so much going on in terms of research and advancement in batteries. What are the primary areas being studied?
Advances are being made in so many areas. One area of high-level focus is in the U.S. Department of Energy’s plan for grid energy storage, which was put out in 2013. It prioritized the research into four bins: cost-competitive technology development, validated safety and reliability, an equitable regulatory environment, and industry acceptance. We’ve seen heavy investment in each of these areas across many industry sectors, and there have been advancements every year.
Improvements are being made consistently.
What advancements have been made specifically on the safety side of the research?
Research and development are improving our understanding of safety and controls every year. Here’s an example. When the lithium ion battery goes into thermal runaway, it can often off-gas and vent, and the vent gases can build up in an enclosed space and become combustible. Historically, this has not really been a hazard that we have had to deal with because most lithium ion batteries were used in personal electronics and perhaps in cars. Car engines and cell phones are not in enclosed spaces and so you don’t get gas buildup during a thermal runaway event. But we now know to design for it in stationary lithium ion battery installations because they are being put into small cabinets. So just the understanding of the various properties of batteries in different applications has been something that has evolved over the last few years. And that is just one case study in a deepening understanding of the hazards themselves and the technology itself leading to better design. I have seen that better design make its way into the systems that are being installed now. There is an understanding of controlling the hazards that wasn’t necessarily there five or 10 years ago.