Solar panels are designed to withstand high temperatures, but extreme heat can reduce their efficiency and longevity. The key factors that determine how solar panels perform in hot weather are the panel technology, mounting and placement, and the climate conditions.
In general, most solar panels today are engineered to operate efficiently at temperatures up to 77°C (170°F). As temperatures rise above this level, solar panel output declines. Temperatures above 85°C (185°F) can start to damage parts of the panel.
Prolonged exposure to high heat causes thermal expansion and contraction that stresses materials over time. Hot spots on panels can develop microcracks and degrade faster. The adhesive holding panels together can loosen and electrical components can fail prematurely.
Fortunately, there are solutions to minimize solar panel failures in hot climates. Proper solar panel selection, installation techniques, and maintenance can keep solar arrays running efficiently for decades even in extremely hot conditions.
How do high temperatures affect solar panel performance?
Solar panels convert sunlight into electricity through the photovoltaic effect. When photons from sunlight strike the solar cell material, electrons are knocked loose and flow through the material to produce electric current.
This conversion process works best at certain optimal temperatures, typically around 25°C (77°F). As panels heat up, their efficiency drops – the hotter the panel gets, the less electricity it produces.
The main ways high temperatures reduce solar panel performance are:
– Reduced voltage – The electric potential of solar cells decreases as temperature increases. This directly lowers the voltage output.
– Increased resistance – Heating increases electrical resistance in the solar cell material, circuits and connections. More resistance means less current flow and power.
– Heat saturation – When solar cells heat up, the atoms vibrate more intensely. This vibrational energy can interfere with the photons knocking electrons loose, reducing current.
– Thermal mismatch – Different parts of a panel heat up at different rates, creating stresses between materials. This can lower durability and cause microcracks.
– Material degradation – Sustained high heat accelerates breakdown of the solar cell material, encapsulant, backsheet and adhesives.
Fortunately, performance losses due to temperatures up to around 50°C (122°F) are fairly minor, only around 5-10%. But above this point, output falls off more rapidly. Once panels reach 85°C (185°F) they may only produce 75% of their rated wattage.
Solar panel temperature coefficients
Manufacturers rate how much solar panel efficiency declines with increasing temperature using a metric called the temperature coefficient. This measures the percentage drop in output for each degree over 25°C (77°F).
Typical temperature coefficients are:
– Monocrystalline silicon: -0.35%/°C
– Polycrystalline silicon: -0.40%/°C
– Cadmium telluride (CdTe): -0.25%/°C
– Copper indium gallium selenide (CIGS): -0.35%/°C
So a polycrystalline panel would lose about 0.4% of its 25°C (77°F) output for every 1°C increase in temperature. At 100°C it would operate at around 80% of its rated output.
What temperatures damage solar panels?
While high temperatures reduce panel efficiency, the good news is that solar panels can withstand very high heat without any material damage. However, extremely hot spots on panels can start to degrade components once they exceed:
– Silicon cell junction breakdown: Approx. 120°C (248°F)
– Encapsulant softening: Approx. 130°C (266°F)
– Backsheet breakdown: Approx. 150°C (302°F)
These temperatures are far above normal operating range. But in rare cases, intense localized hot spots can develop on panels that exceed these thresholds and cause microcracks and burn marks. This type of thermal degradation is mainly an issue only in installations with flaws that cause excessive heat buildup.
Normal overall panel temperatures above 85°C (185°F) won’t immediately destroy a solar panel. But operating at these elevated temperatures for prolonged periods can accelerate slow thermal breakdown of materials and reduce the panel’s longevity. The international standard IEC 61215 sets a maximum certification temperature of 85°C for qualifying solar panels for safety, durability and performance.
Do solar panels work well in hot climates?
Solar power is extremely popular in hot, arid climates that get abundant sunlight. Top solar countries like Australia, Israel, Mexico, and the United Arab Emirates all have hot desert regions with intense sun and temperatures regularly exceeding 40°C (104°F).
Solar panels can definitely function efficiently and reliably at these “normal” high operating temperatures. But there are certain best practices to follow to ensure success in extremely hot environments:
Solar panel selection
– Choose Tier 1 solar manufacturers that thoroughly test their panels for durability and longevity. Quality panels certified to IEC 61215 standards can withstand desert conditions.
– Select panels with lower temperature coefficients, like monocrystalline or CdTe, for better performance in heat.
– Consider using high-efficiency panel models, which can offset some losses from heat.
– Ensure proper sizing to prevent overheating – allow space between panels for air flow.
Installation methods
– Allow sufficient clearance under panels for cooling airflow. Elevate panels if possible.
– Avoid direct contact between panels and surfaces to prevent conduction heating.
– Use reflective paint or aluminized coatings on mounts, racks and surfaces to reduce heat buildup.
– Create shade structures like solar canopies to shelter panels from intense overhead sunlight.
– Use microinverters or optimizers to minimize local heating of individual panels.
– Avoid excess wiring runs under panels that can heat them from below.
Maintenance tips
– Check panels and connections for damage from thermal stress and expansion.
– Clean panels regularly to maximize output – dirt buildup can drastically increase heat.
– Inspect backsheets and junction boxes for deterioration from sustained heat exposure.
– Verify structural parts are intact, with no loosening or warping from thermal forces.
– Ensure vegetation is controlled to prevent shading issues that create hot spots.
What are the hottest temperatures recorded by solar panels?
Solar panels have survived some incredibly hot conditions in real-world environments:
Death Valley, California
Death Valley holds the record for the hottest air temperature ever recorded, 56.7°C (134°F) in 1913. In 2021, a solar array at the Furnace Creek Visitor Center recorded a panel temperature of 88°C (190°F). The panels kept operating safely at these desert extremes.
Solar furnaces
Solar simulators use giant lenses and mirrors to concentrate sunlight onto solar cells under test. NREL’s simulator can generate the heat equivalent of 10,000 suns, reaching solar cell temperatures above 250°C (482°F). This helps evaluate panel materials and components at extreme temperatures.
Solar One
The Solar One CSP pilot plant near Barstow, California used mirrored troughs focusing sunlight onto a central receiver tower. Salt heat transfer fluid reached temperatures up to 565°C (1050°F) before generating steam to drive a turbine. This demonstrated solar’s potential for super-hot industrial process heat.
Solar panel testing
IEC 61215 certification requires exposing panels to 85°C (185°F) temperatures for 200 hours to test for thermal cycling stability. MIL-STD-810G standards test panels at 93°C (200°F) for electrical failures. This ensures panels won’t fail even at sustained, stressfully high temperatures.
| Location | Record Temperature |
| Death Valley, CA | 88°C (190°F) |
| Solar Furnace | Over 250°C (482°F) |
| Solar One CSP | 565°C (1050°F) |
| IEC Testing | 85°C (185°F) |
| MIL-STD Testing | 93°C (200°F) |
Typical solar panel temperatures in hot climates
Solar panel temperatures vary widely based on conditions like ambient temperature, wind, shading, and panel efficiency. Here are some representative temperatures panels can reach in hot environments:
| Moderate Temperature | Very Hot Temperature | |
| Full sun | 40-60°C (100-140°F) | 65-85°C (150-185°F) |
| Partial shade | 25-40°C (75-100°F) | 50-70°C (120-160°F) |
| Strong wind | Ambient +10°C (50°F) | Ambient + 30°C (85°F) |
| Still air | Ambient +30°C (85°F) | Ambient + 50°C (120°F) |
Actual temperatures depend heavily on site specifics like airflow, shading objects, panel age and tilt angle. But in general, peak summertime panel temperatures between 70-90°C (160-195°F) are common in hot regions under peak sun.
Do solar panels work in Death Valley?
With extreme heat and the hottest air temperatures on Earth, Death Valley is one of the harshest environments for solar panels. But the California desert valley has ample sunshine and also hosts large solar power installations producing emissions-free energy.
The National Park Service installed a 302 kW tracking photovoltaic system at the Furnace Creek Visitor Center in Death Valley in 2021. It provides about half the visitor center’s power.
During peak summertime heat, the solar array has recorded temperatures exceeding 85°C (185°F) on sun-tracking panels. Yet the system has performed reliably even in the desert extremes, producing over 463 MWh of clean energy in its first year.
Other major solar sites have been installed outside the park around Death Valley at locations like the Tecopa Solar Project, Lanfair Solar, and Inyo County’s PV arrays. Generous sun, open land, and proximity to transmission lines outweigh the challenges posed by extreme heat. Careful solar panel selection and installation practices make these facilities achievable.
With a solar resource of over 6 kWh/m2/day and lands unusable for other purposes, Death Valley is a prime example of how solar power can thrive even in one of the hottest places on Earth through proper planning.
Conclusion
While very high temperatures can reduce solar panel efficiency and longevity, modern solar panels are engineered to withstand even extreme heat in harsh desert environments. With proper panel selection, mounting methods, and maintenance, solar arrays can operate for decades in hot climates with minimal degradation. The abundance of solar installations in scorching deserts worldwide demonstrates solar’s resilience and reliability under even the hottest conditions.