Utility Control: The Unseen Dangers of Alternative Power Sources

BY JASON BARKER

Typical fireground operations center on creating safety and eliminating threats. To be prepared to save lives, fire departments drill on hoseline deployment, fire attack skills, search and rescue, securing a water supply, meeting the two-in/two-out standard, ventilation, and salvage and overhaul operations. Often overlooked or an afterthought is securing the utilities.

In California, the typical home and business use natural gas and electricity. In the more rural areas, propane is typically used for heating, cooking, and heating water for bathing and other cleaning chores. With the increased use of consumer solar systems that have battery and generator backup power systems, what once required just a simple turn of a valve and flip of a breaker to secure the utilities has now become complicated.

Uninterruptible Power Supply (UPS) Systems

My volunteer company responded to a gas leak at a local seed research facility. We arrived at the scene and were met by the staff, who reported that a gas valve in a laboratory had been damaged and had been releasing gas for more than an hour before it was discovered. The crew accounted for all the staff; conducted a hazard assessment; determined if anyone needed medical attention; and secured both the natural gas and the electric power, eliminating potential fuel and ignition sources. At first glance, they believed that they had controlled the major hazards but, later in the incident, the company officer realized the computer workstations were still powered; they all had a UPS system.

The building was charged with natural gas, but because the department did not have monitoring equipment, the firefighters did not know if the gas concentration was above, below, or within the flammable range. The container was full of flammable gas, and we didn’t know if the UPS could be an ignition source; we were not as safe as we first thought. As the crew completed their operations, now aware of the overlooked UPS, they noticed additional battery-powered equipment, including the emergency egress lighting and the exit lights. For the incident commander, it is critical to consider such devices as potential ignition sources. Given the right conditions, they could be the source of ignition to create an explosion or a fire.

Though exit and emergency lights and UPS units are common in commercial occupancies, many people use the UPS for their home computers also. Two common systems are in use today: standby UPS and continuous UPS. A standby UPS runs the computer on the normal utility power until it detects a problem. At that point, it very quickly (in five milliseconds or less) turns on the power inverter and runs the computer using the UPS battery. A power inverter simply converts the battery’s direct current (DC) power into 120-volt, 60-Hertz alternating current (AC) power.

In a continuous UPS, the computer is always running on battery power and the battery is being recharged continuously. The battery charger continuously produces DC power that the inverter continuously turns back into 120-volt AC power. If the power fails, the battery provides power to the inverter. There is no switchover time in a continuous UPS. This setup provides a very stable source of power.

Standby UPS systems are far more common for home or small-business use because they tend to cost about half as much as a continuous system. Continuous systems provide extremely clean, stable power, so they tend to be used in server rooms and mission-critical applications. The hazard of UPS for firefighters can be electric shock, heat generation, and the chemical reaction from the charging process. Other locations where you will find UPS and battery backup systems are at cell phone sites and electric utility substations.

Batteries and Explosions

These systems typically use a wet cell lead-acid battery. When these batteries charge, they produce hydrogen, the same gas that ignited in the 1937 Hindenburg airship disaster. If this gas is not properly ventilated, it will accumulate and find an ignition source.

In March 2001, the Sacramento (CA) Metropolitan Fire District responded to a report of a building explosion in Rancho Cordova. On further investigation, they found a computer company’s battery backup system had exploded, several walls had blown over, and there was visible smoke from a room that housed several large batteries. Firefighters also reported that a 40-foot section of the roof was missing just over the area of the explosion.

The energy released by an explosion can injure and even kill responders. Other firefighter concerns can include backup generator systems, which are designed to supply power to the building in a power system failure. These systems must have a means to switch between the utility power and the generator. This switch is typically automatic and will activate when there is any interruption in the utility power supply—e.g., when firefighters turn off the power. This can be a problem when we try to eliminate the electrical hazards at an emergency scene.

Generator Dangers

Preplanning and on-site training with the building maintenance personnel will give fire companies an opportunity to understand how the system works and how to overcome the automatic operation. Even more dangerous to the firefighters are illegal generator hookups that are without the required switch; the power can come from either source. It is common for the do-it-yourselfer to create what is morbidly referred to as a “suicide plug,” an extension cord with two male ends—one that plugs into the generator and the other that plugs into a receptacle in the home. Also associated with the illegal hookup is the improper use of the gasoline-powered generator, which is a common cause of carbon monoxide (CO) poisoning and was the cause of a recent house fire resulting from the heat of the generator’s engine and exhaust. The potential is that an illegally installed generator, remote from where a fire company is operating, may backfeed an entire block of homes, leading to an unseen electric shock hazard. Many utilities may use capacitor banks that store energy to keep a power system energized. Despite the assurance that the power is secured, crews should confirm the power is off before performing overhaul. One option is a personal electrical power sensor (photo 1) that allows for noncontact determination of whether a power line is energized.

(1) Photos by author.

Lithium-Ion Batteries

The use of lithium-ion battery systems is an emerging threat with many documented fatal fires from personal mobility devices such as e-bikes and scooters that have exploded and burned after thermal runaway of the batteries. The Fire Department of New York (FDNY) reports the number of e-battery fires from e-bikes and scooters doubled last year to 220, and the city is on track to surpass last year’s number in 2023. Since January, there have been 63 fires and five deaths.1 The number of electric vehicles on the road powered by lithium-ion batteries is growing, and they are exposing the public and firefighters to uncontrolled fire hazards from a runaway battery condition. My agency responded to a collision involving a Tesla sedan; the resulting fire required four hours and 10,000 gallons of water to stop the battery runaway and resulting fire.

Using lithium-ion battery systems to power homes is also a growing trend. The Tesla Powerwall was the original purpose-built home battery backup energy storage system (ESS). The homeowner who could not afford a Tesla system could create a homemade battery system that may lack the safety and engineering standards of a commercial product. The Tesla system produces 350 to 450 volts DC and 9.4 amps, enough to kill a person, DC or not. Tesla is no longer the sole provider of energy storage systems. DC power requires an inverter to transition the power to the common 120 volts AC to power the home or business. The inverter may be integrated into the home’s power system or it may be used to convert the stored energy from an ESS to power the residence.

Lithium-Iron Phosphate Batteries

The market has many other options other than the lithium-ion battery. A new battery chemistry is the lithium iron phosphate (LiFePO4), which has a longer life span that can have many more charge/discharge cycles than a standard lithium-ion battery. To date, LiFePO4 batteries have not created a battery runaway condition and the associated fires and other dangerous conditions. The structural stability of LiFePO4 results in significantly less heat generation compared to other lithium chemistries.2

Solar Panels

The power company may use a “smart meter” that prevents the solar panels from directly powering a home when the grid is down. This system also prevents backfeeding into the grid, which may endanger power company and fire personnel working where the power system is apparently deenergized.

Most battery systems are charged using photovoltaic solar panels. The panels are typically placed on the roof of a new home, especially in California, where the building code requires the installation of the panels (photo 2). The issue with solar panels is that there is no “off” switch. When the panels are receiving sunlight, power is being produced. New solar panel installations include a means to isolate the solar panels from the home’s breaker panel (photo 3) and typically have numerous warning messages indicating the presence of the system (photo 4). The panels may produce dangerous voltages; damaged wires on the rooftop may expose firefighters to the hazards of the power generated by the panels. To stop the power production, the panel must be shielded from the sun. A heavy opaque salvage cover may be the best method to cover the panels and prevent the production of power.

Hydrogen Fuel Cells

Another power generation option is the use of a hydrogen fuel cell to create a microgrid to support the operations of businesses to reduce their carbon footprint. A home-improvement store chain plans on using the fuel cell system to power a warehouse in Texas, and other systems supported the operation of several locations in New York state during a blackout.

Off the Grid and Do-It-Yourselfers

The off-grid lifestyle may also pose an issue with securing power supplies to those homes. Many people living off grid are accomplished do-it-yourselfers who create their own power sources that lack the safety features of a commercial application. It may be a small hydroelectric generator, a wind turbine, solar panels, or a combination of all three that powers the home and creates independence from the power companies.

So, the next time you are assigned to secure the utilities, realize that you may have not completely deenergized the building. The use of UPS, battery backups, and generator systems may continue to provide power and ignition sources in the building.

Many alternative means to power homes and businesses are now used; the once simple task of securing the power has become complex. Firefighters may require additional training to safely secure the power and ensure that they can operate without fear of being injured by an electric shock or an arc that may create an unexpected ignition source.

ENDNOTES

1. Krauth, Dan. (2023) Deadly dilemma: NYC searching for effective measures to regulate lithium-ion batteries, WABC-TV. https://abc7ny.com/lithium-ion-batteries-fire-fdny-battery-fires/13155112/.

2. Israeli Industrial Batteries (IIB). Safety of Lithium Iron Phosphate (LiFePO4) Batteries. https://www.iib.co.il/upload/1529315153.pdf.

JASON BARKER is a battalion chief, a training officer, a paramedic, and a 22-year veteran with the Dixon (CA) Fire Department. He also serves as the assistant chief with the Willow Oak Fire Department, with which he has served 32 years.