In just half a month, three major fires have engulfed rooftops in three different countries. Recently, three seemingly unrelated fires—one in a domestic chemical plant, one in a cold chain warehouse across the ocean, and one in a European residential building—all pointed to rooftop photovoltaic (PV) modules. With summer approaching, a peak fire season, rooftop PV fires are evolving from isolated incidents into a new and increasingly prevalent type of fire in factories and buildings, quietly affecting the entire PV industry.
Why would a PV module, meant to quietly generate electricity, become involved in a fire? Examining the aftermath of these three incidents reveals that their costs are far greater than simply "catching fire."
On June 13th, a fire broke out at the paraffin material yard of the Yanggu Huatai Yanggu plant. Thick black smoke rose tens of meters high, accompanied by multiple explosions. The fire took several hours to bring under control, resulting in three injuries. This factory is the company's core production base. Production was halted immediately after the fire, and the company announced it would significantly impact its 2026 performance. The stock price also experienced a sharp drop of over 10% on the secondary market. As of now, the cause of the fire is still under investigation, but photos from the scene show that the large-scale photovoltaic modules installed on the warehouse roof were simultaneously ignited by the fire, once again bringing the relationship between photovoltaic modules and building fires into the spotlight.
Looking across the ocean, on June 17th, a fire broke out in a 46,000-square-meter cold chain warehouse belonging to Lineage Logistics, a global cold chain giant, in Boyle Heights, Los Angeles. According to tenant statements, a third-party contractor was testing a photovoltaic array on the roof when the fire started, and preliminary investigations suggest this work may have been the trigger. Simultaneously with the rooftop photovoltaic system igniting, ammonia pipes inside the building were also affected and ruptured, resulting in multiple explosions. The fire department issued an evacuation order, and the governor of California declared a state of emergency. The fire burned for several days, and by the fifth day it was still not completely extinguished.
Around the same time, residential rooftops in Europe were also damaged. On June 9th, a fire broke out in a residential building in Clervo, Germany, and spread to the roof. Because the roof was constructed of photovoltaic modules combined with green roofing, which become electrified when exposed to sunlight, 42 firefighters were deployed, and the firefighting effort on the roof alone lasted approximately 5 hours. In recent months, Germany has seen a series of residential rooftop solar-powered fires. In one incident, a firefighter was electrocuted and hospitalized while dismantling the roof to fight the fire because the photovoltaic modules were still electrified.
In these cases, the photovoltaic modules are sometimes the cause of the fire, and sometimes a variable that allows the fire to spread. But regardless of their role, one signal is clear: as distributed solar power is rapidly being installed in factories, warehouses, and residences, module safety is no longer just a matter of product manufacturing; it is a challenge that building safety, production safety, and subsequent operation and maintenance must all address.
Layered Hidden Dangers: Module Fires Are Far More Than Just a "Fire"
Based on publicly available accident information and industry analysis, the fire risk of distributed photovoltaic (PV) power stations often stems from a combination of factors. Common triggers include hot spot effects and DC arcing. Quality issues are also a contributing factor to PV fires.
A hot spot, simply put, is "a disaster caused by a shadow." When the surface of a module is obscured by bird droppings, fallen leaves, or accumulated dust, the obscured cells cannot generate electricity normally. Instead, they act as a load, consuming energy from other cells, leading to a rapid increase in local temperature. This can accelerate module aging or, in severe cases, directly ignite surrounding materials. DC arcing is even more insidious: the DC side voltage of a PV system is typically as high as 600 to 1000 volts. Loose connections, damaged cables, or deteriorated insulation can all generate arcs, and sustained arcs can reach temperatures of 3000 to 7000°C, enough to instantly carbonize components, burn through structural steel, and propagate into the space below. A power station has hundreds or even thousands of connections; a single loose connection can become a source of fire.
Beyond technological risks, inherent quality issues within the industry are amplifying the overall risk. At a photovoltaic industry seminar in 2025, an industry insider bluntly stated: "In the past two years, companies have been selling at a loss, making silicon wafers, frames, glass, and encapsulant films thinner and thinner. There's no elasticity left; how can problems not occur?" This is not alarmist—data from the National Solar Photovoltaic Product Quality Inspection and Testing Center shows that the overall pass rate of photovoltaic modules has declined from 100% in 2019 to 62.9% in 2024, with the pass rate for key auxiliary materials such as solder strips and junction boxes even falling below 50%. Falsely labeling power output and thinning materials may seem like cost-cutting in the short term, but in the long term, they could translate into reduced power generation, hot spots, and even fire hazards.
The truly troublesome aspect of photovoltaic fires is often not the fire itself, but the electrical components. Firefighters often find upon arrival that the roof cannot be directly dismantled—it's covered in solar panels, generating electricity as long as there's sunlight, maintaining a continuous DC high voltage during the day, unlike AC power which can be easily cut off by simply switching off the main switch. Using water to extinguish the fire could cause splashing when it comes into contact with flammable materials like paraffin wax, actually increasing the risk. Furthermore, the presence of solar panels alters the fire's spread path, often rendering conventional firefighting tactics ineffective. Industry insiders in both firefighting and solar power admit that the difficulty of rescuing people from rooftop solar fires has long been underestimated, and the industry still lacks mature and executable rescue plans.
This is why the National Fire Protection Association (NFPA) in the United States specifically requires rooftop photovoltaic (PV) systems to be equipped with fast shutdown devices in NEC 690.12, which must reduce the voltage outside the array boundary to below 30 volts within 30 seconds of activation to protect firefighters working on the roof. Germany promotes the installation of "fire-fighting switches" through standards such as VDE-AR-E 2100-712. Many markets, including the United States, Australia, Europe, and Japan, have made module-level fast shutdown mandatory or explicitly required. In China, the National Energy Administration also requires distributed PV projects to install arc fault circuit interrupters (AFCI) or use modules with corresponding functions. All countries are pointing to the same principle—in PV-related fires, the most deadly element is often "electricity," not just "fire" itself.
Safety Capabilities First: Moving Modules from "Power Generation Units" to "Protection Terminals"
If fire cases expose the results, then hot spots, arcing, and quality fluctuations point to the process of risk formation. Therefore, rooftop PV safety cannot rely solely on post-accident investigation and accountability. A more realistic approach is to incorporate safety capabilities into the design and operation management of components and power plants, enabling risks to be identified, located, and addressed at an early stage. Ultimately, this means shifting from "firefighting" to "fire prevention," extinguishing potential hazards before they escalate into fires.
In industry exploration, component safety technology is moving from passive to active protection. Areas such as AFCI arc detection, component-level rapid shutdown, insulation monitoring, hot spot diagnosis, and flame-retardant encapsulation are all being discussed. Recently, Sungrow Power's 5S intelligent components focus on "self-diagnosis" and "self-shutdown": the former collects real-time operational data such as component voltage, current, and temperature, allowing fire hazards like arcing and hot spots to be identified and located before they ignite; the latter emphasizes dual safety shutdown at the component and system levels, rapidly cutting off DC high voltage in fault or extreme situations, blocking the risk of electrical fires and their spread at the source, and reducing the voltage across the entire plant to a safe level within 25 seconds. Integrating anomaly detection and rapid shutdown into the modules themselves transforms them from passive "power generation units" into proactive "safety terminals."
From chemical plants to cold chain warehouses, and then to residential rooftops, three major fires within half a month serve as a warning to the rapidly growing photovoltaic industry: as distributed photovoltaic systems are deployed across the rooftops of various industries, this rapid expansion cannot neglect the most fundamental guarantee of safety. Objectively speaking, photovoltaic power station fires are essentially probabilistic events, often resulting from quality defects, inadequate construction and maintenance, or a combination of extreme operating conditions, rather than being inherently flawed in the photovoltaic system itself. Precisely because it is a predictable and controllable probabilistic risk, incorporating safety measures into products in advance, and providing "safety insurance" for every rooftop and every power station, demonstrates its long-term value.
