What is LID (Light Induced Degradation)?
A small, one-off drop in output that some panels experience in their first hours of sunlight.
Quick Answer
LID is factored into the panel rating you are quoted, so it does not come as a surprise in real-world UK output. If you are comparing panels, note that N-type options (TOPCon, HJT, IBC) avoid most LID and so hold their output slightly better over a 25-year life.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
LID (Light Induced Degradation) Explained
LID (Light Induced Degradation) is a small, permanent loss of output that occurs when a solar panel is first exposed to sunlight, typically in the first hours to days. It is caused by boron-oxygen defects in P-type silicon and usually costs 1 to 3 percent of output. Manufacturers account for LID in their rated power and warranty. N-type cells largely avoid LID because they are not boron-doped, which is one reason the industry has shifted from P-type PERC to N-type technologies.
How Does LID (Light Induced Degradation) Work in the UK?
LID is factored into the panel rating you are quoted, so it does not come as a surprise in real-world UK output. If you are comparing panels, note that N-type options (TOPCon, HJT, IBC) avoid most LID and so hold their output slightly better over a 25-year life.
Frequently Asked Questions
What is light induced degradation in solar panels?
LID is a small, permanent drop in output (usually 1 to 3 percent) that some panels experience in their first hours of sun exposure, caused by boron-oxygen defects in P-type silicon. It is already accounted for in the panel's rated power.
Do N-type panels suffer from LID?
N-type panels largely avoid LID because they are not boron-doped, so they do not have the boron-oxygen defects that cause it. This is one reason N-type technologies like TOPCon and HJT hold their output slightly better than older P-type PERC panels.
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John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.