Hotspots are one of the most common, and most overlooked, issues in solar energy systems. A single hotspot can silently slash your energy output, shorten panel lifespan, and, in worst cases, create fire risks. If you’re managing commercial or utility-scale PV projects in the US, understanding hotspots isn’t optional, it’s critical for protecting your ROI.

What Exactly Is a Hotspot?
A hotspot is a local area on a solar panel that heats up much more than the rest of the module. This usually happens when one or more cells are shaded, cracked, or defective. Because solar cells are connected in series, healthy cells force current through the impaired one, pushing it into reverse bias — where it stops generating power and starts acting like a resistor. The result? Localized heating that can climb 20–80°C higher than neighboring cells.

Why Are Hotspots Such a Big Deal?

1. Energy Loss
   Even a single defective cell can drop the power output of an entire string. This directly impacts energy yield and raises your levelized cost of energy (LCOE).

2. Permanent Module Damage
   Hotspots degrade encapsulants, cause browning or backsheet discoloration, and can lead to solder joint failure. Repeated stress results in permanent efficiency loss and reduced service life.

3. Safety Hazards
   Severe hotspots can exceed 150°C — hot enough to cause burn marks, insulation breakdown, or even fires.

4. Financial Impact
   Reduced energy output + replacement costs = lower ROI and higher O&M budgets.

What Causes Hotspots?
Soiling: Dust, bird droppings, or leaves create partial shading.

Micro-cracks: Often from mechanical stress, hail, or mishandling during installation.

Manufacturing defects: Poor soldering, misaligned cells, or lamination voids.

Aging: Potential-Induced Degradation (PID) and thermal cycling over time.

Poor design or installation: String mismatch, bypass diode failure, or uneven loading.

How Do You Detect Them?
Infrared (IR) thermography: Quick field scans to identify temperature spikes.

Electroluminescence (EL) imaging: Finds micro-cracks and inactive cells.

IV curve tracing: Detects mismatch losses and abnormal currents.

How Do You Prevent or Fix Hotspots?

1. Robotic or Automated Cleaning
   Use water-efficient cleaning robots to remove soiling without scratching modules — critical in desert and dusty environments.

2. Smarter Site Design
   Run shading analysis before installation (PVsyst, Helioscope). Position arrays to minimize obstructions and ensure uniform sunlight.

3. Quality Hardware
   Choose IEC 61215/61730-certified modules with robust bypass diodes. Inspect modules during commissioning to catch early defects.

4. Regular Inspections
   Perform annual or semi-annual thermographic scans. Address issues early through cleaning, rewiring, or module replacement.

Bottom Line
Hotspots aren’t just a technical issue — they’re a financial one. Proactive cleaning, smart monitoring, and regular inspections can protect energy yield, extend module life, and safeguard your solar investment. Whether you manage 100 kW rooftops or 300 MW utility-scale sites, addressing hotspots early is one of the simplest ways to boost performance and lower O&M costs.